IB Biology SL Flashcards: Complete Course Review
Review the current IB Biology Standard Level course with 960 independently written active-recall cards covering all 34 SL topics across molecules, cells, organisms, genetics, evolution, and ecology.
O ovom špilu
Study the current IB Biology SL course with 960 independently written English flashcards. The deck covers all 34 Standard Level topics through four broad groups: molecules and cells; metabolism and genetics; organisms and systems; and evolution and ecology.
Cards move from essential terms and structures to functions, mechanisms, comparisons, predictions, and compact interpretation prompts. Useful two-way term cards are separated by at least three unrelated cards, while explanatory answers are kept in the direction that supports meaningful recall. Every card carries the root tag ib-bio-sl and exactly one broad group tag.
The order introduces prerequisite ideas before dependent ones and progresses from simpler recall to more demanding reasoning within each topic. The deck is designed for ongoing spaced review. It does not replace data-heavy practice papers, extended-response practice, laboratory work, or the scientific investigation.
Reviewed in 2026 against the current Biology Standard Level course, first assessed in 2025.
Independent, unofficial study aid based on common biological knowledge. Not affiliated with or endorsed by the International Baccalaureate Organization. No copied IB examination questions, mark schemes, or curriculum text are included.
Check the official IB Biology course page for authoritative requirements.
Kartice u ovom špilu
Kartica 1
Pitanje
What is water polarity?
Odgovor
The unequal sharing of electrons in a water molecule, giving oxygen a partial negative charge and the hydrogens partial positive charges.
Kartica 2
Pitanje
What is a hydrogen bond?
Odgovor
A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule.
Kartica 3
Pitanje
What is cohesion?
Odgovor
Attraction between molecules of the same substance.
Kartica 4
Pitanje
What is adhesion?
Odgovor
Attraction between molecules of different substances.
Kartica 5
Pitanje
Which term describes unequal charge distribution within a water molecule?
Odgovor
water polarity
Kartica 6
Pitanje
Which term describes the intermolecular attraction that links neighboring water molecules?
Odgovor
a hydrogen bond
Kartica 7
Pitanje
Which term describes attraction between molecules of the same substance?
Odgovor
cohesion
Kartica 8
Pitanje
Which term describes attraction between water and a different material?
Odgovor
adhesion
Kartica 9
Pitanje
What is a solvent?
Odgovor
A liquid that dissolves solutes to form a solution.
Kartica 10
Pitanje
What is specific heat capacity?
Odgovor
The energy required to raise the temperature of a unit mass of a substance by one degree.
Kartica 11
Pitanje
What is latent heat of vaporization?
Odgovor
The energy required to vaporize a specified amount of liquid without changing its temperature.
Kartica 12
Pitanje
Why does ice float on liquid water?
Odgovor
Hydrogen bonds hold water molecules in an open lattice in ice, making ice less dense than liquid water.
Kartica 13
Pitanje
Which term describes a liquid that dissolves solutes?
Odgovor
a solvent
Kartica 14
Pitanje
Which term describes the energy needed to raise a unit mass by one degree?
Odgovor
specific heat capacity
Kartica 15
Pitanje
Which term describes the energy needed to vaporize a liquid without a temperature change?
Odgovor
latent heat of vaporization
Kartica 16
Pitanje
Which property of water makes sweating an effective cooling mechanism?
Odgovor
Water absorbs substantial energy as it evaporates; the highest-energy molecules leave, carrying heat away from the skin.
Kartica 17
Pitanje
Why does water resist rapid temperature change?
Odgovor
Many hydrogen bonds must absorb energy before molecular motion increases substantially, giving water a high specific heat capacity.
Kartica 18
Pitanje
How do cohesion and adhesion support water transport in narrow tubes?
Odgovor
Cohesion keeps water molecules connected, while adhesion helps the water column cling to the tube wall.
Kartica 19
Pitanje
How does water participate differently in hydrolysis and condensation?
Odgovor
Hydrolysis consumes water to split a bond; condensation forms a bond and releases water.
Kartica 20
Pitanje
How does floating ice protect aquatic life in winter?
Odgovor
Surface ice insulates the liquid water below, slowing further heat loss and preventing the whole body of water from freezing rapidly.
Kartica 21
Pitanje
Why is water effective for transporting many biological solutes?
Odgovor
Its polarity allows ions and other polar molecules to become surrounded and dispersed in solution.
Kartica 22
Pitanje
Why do nonpolar substances tend to cluster in water?
Odgovor
Clustering reduces the nonpolar surface exposed to water, allowing more water molecules to maintain hydrogen-bond interactions.
Kartica 23
Pitanje
What is a nucleotide?
Odgovor
A nucleic-acid monomer made of a pentose sugar, a phosphate group, and a nitrogenous base.
Kartica 24
Pitanje
What is a nucleoside?
Odgovor
A nitrogenous base joined to a pentose sugar, without a phosphate group.
Kartica 25
Pitanje
What is a phosphodiester bond?
Odgovor
A covalent bond linking the phosphate of one nucleotide to the sugar of the next nucleotide.
Kartica 26
Pitanje
What is DNA?
Odgovor
A usually double-stranded nucleic acid that stores hereditary information in its base sequence.
Kartica 27
Pitanje
Which term describes a sugar-phosphate-base monomer?
Odgovor
a nucleotide
Kartica 28
Pitanje
Which term describes a base joined to a sugar but no phosphate?
Odgovor
a nucleoside
Kartica 29
Pitanje
Which term describes the covalent linkage in a nucleic-acid sugar-phosphate backbone?
Odgovor
a phosphodiester bond
Kartica 30
Pitanje
Which term describes the nucleic acid that usually stores hereditary information?
Odgovor
DNA
Kartica 31
Pitanje
What is RNA?
Odgovor
A usually single-stranded nucleic acid involved in expressing and regulating genetic information.
Kartica 32
Pitanje
What are antiparallel DNA strands?
Odgovor
Two DNA strands that run in opposite 5′ to 3′ directions.
Kartica 33
Pitanje
What is complementary base pairing?
Odgovor
Specific pairing in which adenine pairs with thymine in DNA, or uracil in RNA, and cytosine pairs with guanine.
Kartica 34
Pitanje
What is a purine?
Odgovor
A nitrogenous base with two fused rings; adenine and guanine are purines.
Kartica 35
Pitanje
Which term describes the usually single-stranded nucleic acid used in gene expression?
Odgovor
RNA
Kartica 36
Pitanje
Which term describes DNA strands running in opposite directions?
Odgovor
antiparallel DNA strands
Kartica 37
Pitanje
Which term describes specific A–T or A–U and C–G pairing?
Odgovor
complementary base pairing
Kartica 38
Pitanje
Which term describes a two-ring nitrogenous base?
Odgovor
a purine
Kartica 39
Pitanje
What is a pyrimidine?
Odgovor
A nitrogenous base with one ring; cytosine, thymine, and uracil are pyrimidines.
Kartica 40
Pitanje
What is a genome?
Odgovor
The complete genetic material of an organism or cell.
Kartica 41
Pitanje
What three structural features commonly distinguish RNA from DNA?
Odgovor
RNA usually contains ribose, uses uracil instead of thymine, and is single-stranded rather than double-stranded.
Kartica 42
Pitanje
What determines the base sequence of the second DNA strand?
Odgovor
Complementary base-pairing rules determine it: A pairs with T, and C pairs with G.
Kartica 43
Pitanje
Which term describes a one-ring nitrogenous base?
Odgovor
a pyrimidine
Kartica 44
Pitanje
Which term describes the complete genetic material of an organism?
Odgovor
a genome
Kartica 45
Pitanje
What do the 5′ and 3′ labels of a nucleic-acid strand refer to?
Odgovor
They refer to numbered carbon atoms in the pentose sugar and define the strand's chemical direction.
Kartica 46
Pitanje
Where is genetic information encoded in DNA?
Odgovor
In the order of nitrogenous bases along the DNA strand.
Kartica 47
Pitanje
Why is ATP classified as a nucleotide?
Odgovor
It contains adenine, ribose, and phosphate groups, the three component types of a nucleotide.
Kartica 48
Pitanje
How do mRNA, tRNA, and rRNA contribute to protein synthesis?
Odgovor
mRNA carries the coding sequence, tRNA delivers amino acids, and rRNA forms the catalytic and structural core of ribosomes.
Kartica 49
Pitanje
How are a gene and a chromosome related?
Odgovor
A gene is a DNA sequence with a biological function; a chromosome is one long DNA molecule containing many genes and other sequences.
Kartica 50
Pitanje
What happens to double-stranded DNA when it is denatured by heat?
Odgovor
Hydrogen bonds between complementary bases break and the two strands separate; the covalent backbones usually remain intact.
Kartica 51
Pitanje
Why can each DNA strand serve as a template during replication?
Odgovor
Its base sequence determines a complementary sequence through specific base pairing.
Kartica 52
Pitanje
In which direction are new nucleic-acid strands synthesized?
Odgovor
Nucleotides are added to the 3′ end, so synthesis proceeds 5′ to 3′.
Kartica 53
Pitanje
What is a monosaccharide?
Odgovor
A single sugar unit that can serve as a carbohydrate monomer.
Kartica 54
Pitanje
What is a disaccharide?
Odgovor
A carbohydrate formed from two monosaccharides joined by a glycosidic bond.
Kartica 55
Pitanje
What is a polysaccharide?
Odgovor
A polymer made from many monosaccharide units.
Kartica 56
Pitanje
What is a glycosidic bond?
Odgovor
A covalent bond joining monosaccharides in a carbohydrate.
Kartica 57
Pitanje
Which term describes a single sugar unit?
Odgovor
a monosaccharide
Kartica 58
Pitanje
Which term describes two monosaccharides joined together?
Odgovor
a disaccharide
Kartica 59
Pitanje
Which term describes a polymer of many sugar units?
Odgovor
a polysaccharide
Kartica 60
Pitanje
Which term describes the covalent linkage between monosaccharides?
Odgovor
a glycosidic bond
Kartica 61
Pitanje
What is a triglyceride?
Odgovor
A lipid formed from glycerol joined to three fatty acids.
Kartica 62
Pitanje
What is a fatty acid?
Odgovor
A hydrocarbon chain with a carboxyl group that can form part of many lipids.
Kartica 63
Pitanje
What is a saturated fatty acid?
Odgovor
A fatty acid with no carbon-carbon double bonds in its hydrocarbon chain.
Kartica 64
Pitanje
What is a phospholipid?
Odgovor
An amphipathic lipid with a phosphate-containing hydrophilic head and hydrophobic fatty-acid tails.
Kartica 65
Pitanje
Which term describes glycerol joined to three fatty acids?
Odgovor
a triglyceride
Kartica 66
Pitanje
Which term describes a hydrocarbon chain ending in a carboxyl group?
Odgovor
a fatty acid
Kartica 67
Pitanje
Which term describes a fatty acid without carbon-carbon double bonds?
Odgovor
a saturated fatty acid
Kartica 68
Pitanje
Which term describes a lipid with a polar head and nonpolar tails?
Odgovor
a phospholipid
Kartica 69
Pitanje
How is a glycosidic bond formed between two monosaccharides?
Odgovor
A condensation reaction joins them and releases a molecule of water.
Kartica 70
Pitanje
How is a polysaccharide broken into smaller sugars?
Odgovor
Hydrolysis adds water across glycosidic bonds, splitting the polymer.
Kartica 71
Pitanje
Which polysaccharides store glucose in plants and animals?
Odgovor
Starch stores glucose in plants; glycogen stores glucose in animals and fungi.
Kartica 72
Pitanje
Why is cellulose suitable for plant cell walls?
Odgovor
Its straight β-glucose chains hydrogen-bond into strong microfibrils that resist stretching.
Kartica 73
Pitanje
Why do lipids store more energy per gram than carbohydrates?
Odgovor
Lipids contain more energy-rich carbon-hydrogen bonds and are more reduced.
Kartica 74
Pitanje
Why do phospholipids form bilayers in water?
Odgovor
Hydrophilic heads interact with water while hydrophobic tails cluster away from water.
Kartica 75
Pitanje
Besides energy storage, what are three biological roles of lipids?
Odgovor
They form membranes, provide thermal insulation and cushioning, and can act as signaling molecules.
Kartica 76
Pitanje
How do cis double bonds affect fatty-acid packing and melting point?
Odgovor
They introduce bends that reduce close packing, usually lowering the melting point.
Kartica 77
Pitanje
What is an amino acid?
Odgovor
A protein monomer with an amino group, a carboxyl group, a hydrogen, and a variable R group attached to a central carbon.
Kartica 78
Pitanje
What is a peptide bond?
Odgovor
The covalent bond formed between the amino group of one amino acid and the carboxyl group of another.
Kartica 79
Pitanje
What is a polypeptide?
Odgovor
A chain of amino acids joined by peptide bonds.
Kartica 80
Pitanje
What is protein primary structure?
Odgovor
The amino-acid sequence of a polypeptide.
Kartica 81
Pitanje
Which term describes a protein monomer with amino, carboxyl, and variable R groups?
Odgovor
an amino acid
Kartica 82
Pitanje
Which term describes the covalent linkage between amino acids?
Odgovor
a peptide bond
Kartica 83
Pitanje
Which term describes a chain of peptide-linked amino acids?
Odgovor
a polypeptide
Kartica 84
Pitanje
Which term describes a protein's amino-acid sequence?
Odgovor
protein primary structure
Kartica 85
Pitanje
What is protein secondary structure?
Odgovor
Local folding such as α-helices and β-sheets stabilized mainly by backbone hydrogen bonds.
Kartica 86
Pitanje
What is protein tertiary structure?
Odgovor
The overall three-dimensional shape of one polypeptide produced by interactions among R groups and the backbone.
Kartica 87
Pitanje
What is protein quaternary structure?
Odgovor
The arrangement of multiple polypeptide subunits in one functional protein.
Kartica 88
Pitanje
What is protein denaturation?
Odgovor
Loss of a protein's normal three-dimensional shape and therefore usually its function.
Kartica 89
Pitanje
Which term describes local α-helix and β-sheet folding?
Odgovor
protein secondary structure
Kartica 90
Pitanje
Which term describes the overall three-dimensional shape of one polypeptide?
Odgovor
protein tertiary structure
Kartica 91
Pitanje
Which term describes the association of multiple polypeptide subunits?
Odgovor
protein quaternary structure
Kartica 92
Pitanje
Which term describes loss of a protein's native shape?
Odgovor
protein denaturation
Kartica 93
Pitanje
What mainly gives different amino acids their different chemical properties?
Odgovor
Their variable R groups.
Kartica 94
Pitanje
What reaction forms a peptide bond?
Odgovor
A condensation reaction releases water as the amino and carboxyl groups join.
Kartica 95
Pitanje
Why can high temperature denature a protein?
Odgovor
Increased molecular motion disrupts weak interactions that maintain the protein's shape.
Kartica 96
Pitanje
Why can extreme pH denature a protein?
Odgovor
It changes the charges of R groups and disrupts ionic and hydrogen-bond interactions.
Kartica 97
Pitanje
How do fibrous and globular proteins generally differ?
Odgovor
Fibrous proteins are elongated and mainly structural; globular proteins are compact and often perform dynamic functions.
Kartica 98
Pitanje
Why is three-dimensional shape crucial to protein function?
Odgovor
It creates specific binding, catalytic, structural, or interaction surfaces.
Kartica 99
Pitanje
Name four broad biological roles of proteins.
Odgovor
Catalysis, transport, signaling, defense, movement, and structural support are major roles; any four are sufficient.
Kartica 100
Pitanje
How can changing one amino acid alter protein function?
Odgovor
The substitution can change R-group interactions, folding, stability, or an active or binding site.
Kartica 101
Pitanje
What is cell theory?
Odgovor
The principles that living organisms are made of cells, cells are the basic units of life, and cells arise from pre-existing cells.
Kartica 102
Pitanje
What is a prokaryotic cell?
Odgovor
A cell without a nucleus or other membrane-bound organelles.
Kartica 103
Pitanje
What is a eukaryotic cell?
Odgovor
A cell with DNA enclosed in a nucleus and with membrane-bound organelles.
Kartica 104
Pitanje
What is the nucleus?
Odgovor
The double-membrane organelle that contains most of a eukaryotic cell's DNA.
Kartica 105
Pitanje
Which term describes the principles describing cells as life's basic units?
Odgovor
cell theory
Kartica 106
Pitanje
Which term describes a cell lacking a nucleus and membrane-bound organelles?
Odgovor
a prokaryotic cell
Kartica 107
Pitanje
Which term describes a cell with a nucleus and membrane-bound organelles?
Odgovor
a eukaryotic cell
Kartica 108
Pitanje
Which term describes the organelle containing most eukaryotic DNA?
Odgovor
the nucleus
Kartica 109
Pitanje
What is a ribosome?
Odgovor
A molecular complex of rRNA and proteins that synthesizes polypeptides.
Kartica 110
Pitanje
What is the cytoplasm?
Odgovor
The material inside the plasma membrane but outside the nucleus, including cytosol and organelles.
Kartica 111
Pitanje
What is the plasma membrane?
Odgovor
The selectively permeable boundary separating a cell from its environment.
Kartica 112
Pitanje
What is a cell wall?
Odgovor
A rigid extracellular layer that supports and protects cells in plants, fungi, and most prokaryotes.
Kartica 113
Pitanje
Which term describes the complex that synthesizes polypeptides?
Odgovor
a ribosome
Kartica 114
Pitanje
Which term describes cell contents inside the plasma membrane but outside the nucleus?
Odgovor
the cytoplasm
Kartica 115
Pitanje
Which term describes the selectively permeable cell boundary?
Odgovor
the plasma membrane
Kartica 116
Pitanje
Which term describes a rigid extracellular support layer?
Odgovor
a cell wall
Kartica 117
Pitanje
What is the nucleoid?
Odgovor
The non-membrane-bound region containing the main chromosome of a prokaryotic cell.
Kartica 118
Pitanje
What is the cytoskeleton?
Odgovor
A dynamic network of protein filaments involved in cell shape, transport, division, and movement.
Kartica 119
Pitanje
What structures are shared by all cells?
Odgovor
A plasma membrane, cytoplasm, genetic material, and ribosomes.
Kartica 120
Pitanje
Which structures distinguish a typical plant cell from a typical animal cell?
Odgovor
A plant cell has a cellulose wall, chloroplasts in photosynthetic tissues, and a large central vacuole; an animal cell lacks these.
Kartica 121
Pitanje
Which term describes the prokaryotic chromosome-containing region?
Odgovor
the nucleoid
Kartica 122
Pitanje
Which term describes the internal network of protein filaments?
Odgovor
the cytoskeleton
Kartica 123
Pitanje
How is genetic material commonly organized in a prokaryotic cell?
Odgovor
The main DNA is usually one circular chromosome in the nucleoid, often accompanied by smaller plasmids.
Kartica 124
Pitanje
How is microscope magnification calculated?
Odgovor
Magnification = image size ÷ actual size, using the same units.
Kartica 125
Pitanje
What does microscope resolution describe?
Odgovor
The ability to distinguish two close points as separate.
Kartica 126
Pitanje
Arrange these from smallest to largest: ribosome, bacterium, animal cell.
Odgovor
Ribosome, bacterium, animal cell.
Kartica 127
Pitanje
How does the cytoskeleton support intracellular transport?
Odgovor
Motor proteins move vesicles and other cargo along cytoskeletal filaments.
Kartica 128
Pitanje
Why does a small cell usually exchange materials more efficiently than a geometrically similar large cell?
Odgovor
It has a larger surface-area-to-volume ratio, providing more exchange surface per unit of cell contents.
Kartica 129
Pitanje
Why is a cell more than a collection of isolated molecules?
Odgovor
Organized interactions among components produce emergent functions such as metabolism, regulation, and reproduction.
Kartica 130
Pitanje
What major advantage do membrane-bound organelles give eukaryotic cells?
Odgovor
They separate incompatible reactions and create specialized local conditions.
Kartica 131
Pitanje
What is a phospholipid bilayer?
Odgovor
A double layer of phospholipids with hydrophilic heads facing water and hydrophobic tails facing inward.
Kartica 132
Pitanje
What is the fluid mosaic model?
Odgovor
A model describing membranes as mobile phospholipids containing a changing mosaic of proteins and other components.
Kartica 133
Pitanje
What is an integral membrane protein?
Odgovor
A protein embedded in the bilayer, often spanning it.
Kartica 134
Pitanje
What is a peripheral membrane protein?
Odgovor
A protein attached to a membrane surface rather than embedded in the bilayer.
Kartica 135
Pitanje
Which term describes a double phospholipid layer with inward-facing tails?
Odgovor
a phospholipid bilayer
Kartica 136
Pitanje
Which term describes the model of a mobile lipid layer containing varied proteins?
Odgovor
the fluid mosaic model
Kartica 137
Pitanje
Which term describes a protein embedded within the lipid bilayer?
Odgovor
an integral membrane protein
Kartica 138
Pitanje
Which term describes a protein attached to a membrane surface?
Odgovor
a peripheral membrane protein
Kartica 139
Pitanje
What is membrane cholesterol?
Odgovor
An amphipathic lipid that buffers membrane fluidity and reduces permeability in animal cells.
Kartica 140
Pitanje
What is a glycoprotein?
Odgovor
A protein with an attached carbohydrate chain, often used in recognition, adhesion, or signaling.
Kartica 141
Pitanje
What is diffusion?
Odgovor
Net movement of particles from a region of higher concentration to lower concentration due to random motion.
Kartica 142
Pitanje
What is osmosis?
Odgovor
Net movement of water across a selectively permeable membrane from higher water potential to lower water potential.
Kartica 143
Pitanje
Which term describes the animal-membrane lipid that buffers fluidity?
Odgovor
membrane cholesterol
Kartica 144
Pitanje
Which term describes a carbohydrate-bearing protein?
Odgovor
a glycoprotein
Kartica 145
Pitanje
Which term describes net movement down a concentration gradient?
Odgovor
diffusion
Kartica 146
Pitanje
Which term describes net water movement across a selectively permeable membrane?
Odgovor
osmosis
Kartica 147
Pitanje
What is facilitated diffusion?
Odgovor
Passive movement down a gradient through a membrane channel or carrier protein.
Kartica 148
Pitanje
What is active transport?
Odgovor
Energy-requiring movement of a substance against its concentration or electrochemical gradient.
Kartica 149
Pitanje
Why is the phospholipid bilayer selectively permeable?
Odgovor
Its hydrophobic interior allows small nonpolar molecules through more readily than ions and most large or polar molecules.
Kartica 150
Pitanje
How do simple diffusion and facilitated diffusion differ?
Odgovor
Both are passive, but facilitated diffusion uses specific membrane proteins while simple diffusion passes through the bilayer.
Kartica 151
Pitanje
Which term describes passive transport through a channel or carrier?
Odgovor
facilitated diffusion
Kartica 152
Pitanje
Which term describes energy-dependent transport against a gradient?
Odgovor
active transport
Kartica 153
Pitanje
How do channel and carrier proteins differ?
Odgovor
Channels provide hydrophilic pores; carriers bind solutes and change shape to move them.
Kartica 154
Pitanje
How can an ATP-driven pump maintain an ion gradient?
Odgovor
It couples ATP hydrolysis to a conformational change that moves ions against their electrochemical gradient.
Kartica 155
Pitanje
How does endocytosis move material into a cell?
Odgovor
The plasma membrane folds inward and pinches off a vesicle containing the material.
Kartica 156
Pitanje
How does exocytosis move material out of a cell?
Odgovor
An intracellular vesicle fuses with the plasma membrane and releases its contents outside.
Kartica 157
Pitanje
What happens to an animal cell in a strongly hypotonic solution?
Odgovor
Water enters by osmosis; without a cell wall, the cell may swell and lyse.
Kartica 158
Pitanje
Does molecular movement stop when diffusion reaches equilibrium?
Odgovor
No. Molecules continue moving randomly, but there is no net movement between regions.
Kartica 159
Pitanje
How does decreasing temperature generally affect membrane fluidity?
Odgovor
It reduces phospholipid movement and makes the membrane less fluid.
Kartica 160
Pitanje
Why do unsaturated fatty-acid tails increase membrane fluidity?
Odgovor
Their cis double-bond bends prevent phospholipids from packing tightly.
Kartica 161
Pitanje
What changes increase the rate of simple diffusion across a membrane?
Odgovor
A steeper gradient, larger surface area, higher temperature, shorter distance, and greater membrane permeability increase the rate.
Kartica 162
Pitanje
What is a mitochondrion?
Odgovor
A double-membrane organelle where most aerobic ATP production occurs.
Kartica 163
Pitanje
What is a chloroplast?
Odgovor
A double-membrane organelle where photosynthesis occurs in plants and algae.
Kartica 164
Pitanje
What is rough endoplasmic reticulum?
Odgovor
A membrane network bearing ribosomes that synthesizes and begins processing many secreted and membrane proteins.
Kartica 165
Pitanje
What is smooth endoplasmic reticulum?
Odgovor
A membrane network involved in lipid synthesis, detoxification, and calcium storage.
Kartica 166
Pitanje
Which term describes the main organelle of aerobic ATP production?
Odgovor
a mitochondrion
Kartica 167
Pitanje
Which term describes the photosynthetic organelle of plants and algae?
Odgovor
a chloroplast
Kartica 168
Pitanje
Which term describes the ribosome-studded membrane network?
Odgovor
rough endoplasmic reticulum
Kartica 169
Pitanje
Which term describes the membrane network that lacks ribosomes and synthesizes lipids?
Odgovor
smooth endoplasmic reticulum
Kartica 170
Pitanje
What is the Golgi apparatus?
Odgovor
Stacked membranes that modify, sort, and package proteins and lipids into vesicles.
Kartica 171
Pitanje
What is a lysosome?
Odgovor
An acidic enzyme-containing organelle that digests macromolecules and worn cellular components.
Kartica 172
Pitanje
What is a vesicle?
Odgovor
A small membrane-bound compartment used for transport, storage, or chemical reactions.
Kartica 173
Pitanje
What is the central vacuole?
Odgovor
A large plant-cell compartment that stores solutes and helps maintain turgor pressure.
Kartica 174
Pitanje
Which term describes the organelle that modifies and sorts cellular cargo?
Odgovor
the Golgi apparatus
Kartica 175
Pitanje
Which term describes the acidic digestive organelle?
Odgovor
a lysosome
Kartica 176
Pitanje
Which term describes a small membrane-bound transport compartment?
Odgovor
a vesicle
Kartica 177
Pitanje
Which term describes the large plant compartment that supports turgor?
Odgovor
the central vacuole
Kartica 178
Pitanje
Why can compartmentalization increase metabolic efficiency?
Odgovor
It concentrates enzymes and substrates, maintains suitable local conditions, and separates incompatible reactions.
Kartica 179
Pitanje
How do mitochondrial cristae support ATP production?
Odgovor
They increase inner-membrane area for electron transport chains and ATP synthase.
Kartica 180
Pitanje
Why are chloroplast thylakoids arranged as extensive membranes?
Odgovor
They provide a large surface for light-absorbing complexes, electron transport chains, and ATP synthase.
Kartica 181
Pitanje
What is the main function of the nucleolus?
Odgovor
It produces rRNA and assembles ribosomal subunits.
Kartica 182
Pitanje
Trace a secreted protein from synthesis to release.
Odgovor
Ribosome on rough ER → ER lumen → transport vesicle → Golgi apparatus → secretory vesicle → plasma membrane → exocytosis.
Kartica 183
Pitanje
Why does a lysosome maintain an acidic interior?
Odgovor
Its hydrolytic enzymes work best at low pH, and acidity helps confine their activity from the cytosol.
Kartica 184
Pitanje
How do the nucleus, ribosomes, ER, and Golgi cooperate in protein production?
Odgovor
DNA instructions are transcribed in the nucleus; ribosomes translate them; ER folds or modifies many products; Golgi further modifies and sorts them.
Kartica 185
Pitanje
How are transport vesicles directed to the correct target membrane?
Odgovor
Specific recognition proteins on vesicles and target membranes interact, allowing selective docking and fusion.
Kartica 186
Pitanje
What is cell differentiation?
Odgovor
The process by which a cell develops specialized structure and function.
Kartica 187
Pitanje
What is a stem cell?
Odgovor
An unspecialized cell able to self-renew and produce differentiated cells.
Kartica 188
Pitanje
What is gene expression?
Odgovor
Use of genetic information to produce a functional RNA or protein product.
Kartica 189
Pitanje
What is a tissue?
Odgovor
A coordinated group of similar or related cells performing a shared function.
Kartica 190
Pitanje
Which term describes development of specialized cell structure and function?
Odgovor
cell differentiation
Kartica 191
Pitanje
Which term describes an unspecialized self-renewing cell?
Odgovor
a stem cell
Kartica 192
Pitanje
Which term describes production of a functional product from genetic information?
Odgovor
gene expression
Kartica 193
Pitanje
Which term describes a group of coordinated cells with a shared function?
Odgovor
a tissue
Kartica 194
Pitanje
What is an organ?
Odgovor
A structure made of multiple tissues working together for particular functions.
Kartica 195
Pitanje
What is the organ-system level of biological organization?
Odgovor
A group of organs that coordinate to perform major functions for an organism.
Kartica 196
Pitanje
What is surface-area-to-volume ratio?
Odgovor
The amount of surface area available relative to the volume it must serve.
Kartica 197
Pitanje
How can two specialized cells have the same genome but different structures?
Odgovor
They express different sets and amounts of genes, producing different proteins and cellular features.
Kartica 198
Pitanje
Which term describes a structure composed of multiple tissue types?
Odgovor
an organ
Kartica 199
Pitanje
Which term describes the level of biological organization formed by coordinated organs?
Odgovor
an organ system
Kartica 200
Pitanje
Which term describes surface area available per unit volume?
Odgovor
surface-area-to-volume ratio
Kartica 201
Pitanje
How is a mammalian red blood cell specialized for oxygen transport?
Odgovor
Its biconcave shape increases exchange area, it is flexible, and loss of its nucleus leaves more space for hemoglobin.
Kartica 202
Pitanje
How is a sperm cell specialized for fertilization?
Odgovor
It has a flagellum for movement, many mitochondria for ATP, a haploid nucleus, and an acrosome containing enzymes.
Kartica 203
Pitanje
How is a neuron specialized for rapid communication?
Odgovor
Long processes carry signals over distance, branching dendrites receive inputs, and synaptic terminals transmit signals to other cells.
Kartica 204
Pitanje
How is a root hair cell specialized for mineral and water uptake?
Odgovor
Its long projection increases surface area, its thin wall shortens the pathway, and membrane transport proteins take up ions.
Kartica 205
Pitanje
How is a palisade mesophyll cell specialized for photosynthesis?
Odgovor
It contains many chloroplasts and is positioned near the upper leaf surface where light is strongest.
Kartica 206
Pitanje
How do ciliated epithelial cells help protect airways?
Odgovor
Their cilia move mucus containing trapped particles and microbes toward the throat.
Kartica 207
Pitanje
Why can extreme specialization reduce a cell's independence?
Odgovor
Resources and structures are committed to a narrow role, so the cell depends on other cells for functions it no longer performs well.
Kartica 208
Pitanje
What is water potential?
Odgovor
The potential energy of water per unit volume relative to pure water, used to predict the direction of water movement.
Kartica 209
Pitanje
What is solute potential?
Odgovor
The negative contribution of dissolved solutes to water potential.
Kartica 210
Pitanje
What is pressure potential?
Odgovor
The contribution of physical pressure to water potential.
Kartica 211
Pitanje
What is turgor pressure?
Odgovor
Outward pressure of a plant-cell interior against its cell wall after water uptake.
Kartica 212
Pitanje
Which term describes the tendency of water to move relative to pure water?
Odgovor
water potential
Kartica 213
Pitanje
Which term describes the water-potential component lowered by dissolved solutes?
Odgovor
solute potential
Kartica 214
Pitanje
Which term describes the water-potential component caused by physical pressure?
Odgovor
pressure potential
Kartica 215
Pitanje
Which term describes pressure of plant-cell contents against the wall?
Odgovor
turgor pressure
Kartica 216
Pitanje
What is plasmolysis?
Odgovor
Separation of the plasma membrane from the cell wall after a plant cell loses water.
Kartica 217
Pitanje
What is a flaccid plant cell?
Odgovor
A plant cell with insufficient turgor pressure to be firm.
Kartica 218
Pitanje
What is an isotonic condition?
Odgovor
A condition in which two solutions have equal effective water potential and no net water movement occurs.
Kartica 219
Pitanje
In which direction does water move across a permeable membrane?
Odgovor
From higher water potential to lower water potential.
Kartica 220
Pitanje
Which term describes membrane separation from the plant cell wall after water loss?
Odgovor
plasmolysis
Kartica 221
Pitanje
Which term describes a plant cell lacking firm turgor?
Odgovor
a flaccid plant cell
Kartica 222
Pitanje
Which term describes equal effective water potential across a membrane?
Odgovor
an isotonic condition
Kartica 223
Pitanje
What is the water potential of pure water at standard pressure?
Odgovor
Zero; adding solute makes water potential more negative.
Kartica 224
Pitanje
How are water potential, solute potential, and pressure potential related?
Odgovor
Water potential equals solute potential plus pressure potential: Ψ = Ψs + Ψp.
Kartica 225
Pitanje
Why does a plant cell usually become turgid rather than burst in a hypotonic solution?
Odgovor
Water entry raises pressure potential, while the rigid cell wall resists further expansion.
Kartica 226
Pitanje
What happens to a plant cell placed in a solution with much lower water potential?
Odgovor
Water leaves the cell, turgor falls, and severe loss can cause plasmolysis.
Kartica 227
Pitanje
Can two solutions have different solute concentrations but equal water potential?
Odgovor
Yes. A difference in pressure potential can offset a difference in solute potential.
Kartica 228
Pitanje
What is an enzyme?
Odgovor
A biological catalyst that increases reaction rate without being consumed.
Kartica 229
Pitanje
What is an active site?
Odgovor
The region of an enzyme where substrate binds and catalysis occurs.
Kartica 230
Pitanje
What is a substrate?
Odgovor
A reactant molecule on which an enzyme acts.
Kartica 231
Pitanje
What is activation energy?
Odgovor
The minimum energy input needed for a reaction to begin.
Kartica 232
Pitanje
Which term describes a biological catalyst?
Odgovor
an enzyme
Kartica 233
Pitanje
Which term describes the substrate-binding catalytic region of an enzyme?
Odgovor
an active site
Kartica 234
Pitanje
Which term describes a reactant bound and changed by an enzyme?
Odgovor
a substrate
Kartica 235
Pitanje
Which term describes the energy barrier that must be overcome for a reaction?
Odgovor
activation energy
Kartica 236
Pitanje
What is the induced-fit model?
Odgovor
The model in which substrate binding changes active-site shape to improve catalytic interactions.
Kartica 237
Pitanje
What is enzyme denaturation?
Odgovor
Loss of the active three-dimensional shape of an enzyme, usually causing loss of activity.
Kartica 238
Pitanje
What is competitive inhibition?
Odgovor
Inhibition caused by a molecule competing with substrate for the active site.
Kartica 239
Pitanje
What is noncompetitive inhibition?
Odgovor
Inhibition caused by binding away from the active site and reducing catalytic function.
Kartica 240
Pitanje
Which term describes the model where substrate binding reshapes the active site?
Odgovor
the induced-fit model
Kartica 241
Pitanje
Which term describes loss of an enzyme's functional shape?
Odgovor
enzyme denaturation
Kartica 242
Pitanje
Which term describes inhibition by active-site competition?
Odgovor
competitive inhibition
Kartica 243
Pitanje
Which term describes inhibition by binding outside the active site?
Odgovor
noncompetitive inhibition
Kartica 244
Pitanje
What is an enzyme optimum?
Odgovor
The condition, such as temperature or pH, at which an enzyme's activity is highest.
Kartica 245
Pitanje
What is feedback inhibition?
Odgovor
Control in which a pathway product inhibits an enzyme acting earlier in the pathway.
Kartica 246
Pitanje
How does an enzyme increase reaction rate?
Odgovor
It stabilizes the transition state and provides a pathway with lower activation energy.
Kartica 247
Pitanje
Why does enzyme activity often rise and then fall as temperature increases?
Odgovor
Molecular collisions initially increase, but excessive heat disrupts enzyme shape and denatures the active site.
Kartica 248
Pitanje
Which term describes the condition producing maximum enzyme activity?
Odgovor
an enzyme optimum
Kartica 249
Pitanje
Which term describes pathway control by inhibition from an end product?
Odgovor
feedback inhibition
Kartica 250
Pitanje
Why does each enzyme have a characteristic pH range?
Odgovor
pH changes the ionization of amino-acid side chains, affecting active-site shape and chemical interactions.
Kartica 251
Pitanje
Why does increasing substrate concentration eventually stop increasing enzyme rate?
Odgovor
At saturation, nearly all active sites are occupied and enzyme concentration limits the maximum rate.
Kartica 252
Pitanje
How does increasing enzyme concentration affect rate when substrate is abundant?
Odgovor
More active sites are available, so the initial rate increases roughly in proportion to enzyme concentration.
Kartica 253
Pitanje
What gives an enzyme substrate specificity?
Odgovor
The active site's shape, charge, polarity, and chemical groups complement particular substrates and transition states.
Kartica 254
Pitanje
What is one practical advantage of immobilizing an enzyme?
Odgovor
The enzyme can be separated from products and reused while conditions around it are controlled.
Kartica 255
Pitanje
Does an enzyme change a reaction's equilibrium position?
Odgovor
No. It speeds forward and reverse reactions but does not change the equilibrium constant or final equilibrium position.
Kartica 256
Pitanje
How can high substrate concentration reduce competitive inhibition?
Odgovor
More substrate molecules increase the chance that substrate rather than inhibitor occupies the active site.
Kartica 257
Pitanje
Why are metabolic reactions commonly organized into pathways?
Odgovor
A sequence of enzyme-controlled steps allows energy changes and intermediates to be controlled and coupled.
Kartica 258
Pitanje
What is ATP?
Odgovor
A nucleotide that transfers usable energy through coupling of its hydrolysis to cellular processes.
Kartica 259
Pitanje
What is cellular respiration?
Odgovor
Controlled release of energy from organic molecules to produce ATP.
Kartica 260
Pitanje
What is glycolysis?
Odgovor
A cytosolic pathway that splits glucose into two pyruvate molecules and yields a small amount of ATP and reduced electron carriers.
Kartica 261
Pitanje
What is pyruvate?
Odgovor
The three-carbon product of glycolysis that can enter aerobic or anaerobic pathways.
Kartica 262
Pitanje
Which term describes the cell's immediate phosphoryl-group energy carrier?
Odgovor
ATP
Kartica 263
Pitanje
Which term describes controlled ATP-producing breakdown of organic molecules?
Odgovor
cellular respiration
Kartica 264
Pitanje
Which term describes the cytosolic splitting of glucose into pyruvate?
Odgovor
glycolysis
Kartica 265
Pitanje
Which term describes the three-carbon product of glycolysis?
Odgovor
pyruvate
Kartica 266
Pitanje
What is aerobic respiration?
Odgovor
Respiration that uses oxygen as the final electron acceptor and produces much more ATP than fermentation.
Kartica 267
Pitanje
What is anaerobic metabolism?
Odgovor
ATP-producing metabolism that proceeds without oxygen.
Kartica 268
Pitanje
What is fermentation?
Odgovor
An anaerobic pathway that regenerates oxidized electron carriers so glycolysis can continue.
Kartica 269
Pitanje
What is oxidation?
Odgovor
Loss of electrons, often accompanied in biology by loss of hydrogen or gain of oxygen.
Kartica 270
Pitanje
Which term describes respiration using oxygen as final electron acceptor?
Odgovor
aerobic respiration
Kartica 271
Pitanje
Which term describes ATP-producing metabolism without oxygen?
Odgovor
anaerobic metabolism
Kartica 272
Pitanje
Which term describes anaerobic regeneration of electron carriers after glycolysis?
Odgovor
fermentation
Kartica 273
Pitanje
Which term describes loss of electrons?
Odgovor
oxidation
Kartica 274
Pitanje
What is reduction?
Odgovor
Gain of electrons, often accompanied in biology by gain of hydrogen or loss of oxygen.
Kartica 275
Pitanje
What is a reduced electron carrier?
Odgovor
A molecule such as NADH that carries high-energy electrons and hydrogen from one reaction to another.
Kartica 276
Pitanje
What is chemiosmosis?
Odgovor
ATP production driven by ions moving down an electrochemical gradient through ATP synthase.
Kartica 277
Pitanje
What is the overall word equation for aerobic respiration of glucose?
Odgovor
Glucose + oxygen → carbon dioxide + water + energy transferred to ATP and heat.
Kartica 278
Pitanje
Which term describes gain of electrons?
Odgovor
reduction
Kartica 279
Pitanje
Which term describes a molecule carrying high-energy electrons between reactions?
Odgovor
a reduced electron carrier
Kartica 280
Pitanje
Which term describes ATP production powered by an ion gradient?
Odgovor
chemiosmosis
Kartica 281
Pitanje
Where does glycolysis occur?
Odgovor
In the cytosol.
Kartica 282
Pitanje
What major stages of aerobic respiration occur in mitochondria?
Odgovor
Pyruvate oxidation and the citric acid cycle occur in the matrix; electron transport and chemiosmosis occur at the inner membrane.
Kartica 283
Pitanje
What is oxygen's direct role in aerobic respiration?
Odgovor
It accepts electrons and hydrogen ions at the end of the electron transport chain, forming water.
Kartica 284
Pitanje
Why does aerobic respiration yield much more ATP per glucose than fermentation?
Odgovor
It transfers electrons through an electron transport chain and uses oxidative phosphorylation, extracting far more of glucose's energy.
Kartica 285
Pitanje
What is the purpose of lactate formation in oxygen-limited animal cells?
Odgovor
It regenerates NAD⁺ so glycolysis can continue producing a small amount of ATP.
Kartica 286
Pitanje
What products are formed during alcoholic fermentation in yeast?
Odgovor
Ethanol and carbon dioxide, while NAD⁺ is regenerated.
Kartica 287
Pitanje
Why is some energy released by respiration transferred as heat rather than captured in ATP?
Odgovor
Energy conversions are not fully efficient, so part of the chemical energy becomes disordered molecular motion.
Kartica 288
Pitanje
What is substrate-level phosphorylation?
Odgovor
Direct transfer of a phosphate group from a metabolic intermediate to ADP to form ATP.
Kartica 289
Pitanje
How does electron transport lead to ATP synthesis in mitochondria?
Odgovor
Electron energy pumps protons across the inner membrane; proton flow back through ATP synthase drives ATP formation.
Kartica 290
Pitanje
Why can intense exercise increase lactate production?
Odgovor
ATP demand can exceed oxygen delivery and aerobic capacity, so cells regenerate NAD⁺ through lactate formation to sustain glycolysis.
Kartica 291
Pitanje
What is photosynthesis?
Odgovor
Conversion of light energy into chemical energy used to synthesize organic molecules from carbon dioxide.
Kartica 292
Pitanje
What is chlorophyll?
Odgovor
A green pigment that absorbs light energy for photosynthesis.
Kartica 293
Pitanje
What is an absorption spectrum?
Odgovor
A graph showing how strongly a pigment absorbs different wavelengths of light.
Kartica 294
Pitanje
What is an action spectrum?
Odgovor
A graph showing the rate or effectiveness of photosynthesis at different wavelengths.
Kartica 295
Pitanje
Which term describes light-driven synthesis of organic molecules from carbon dioxide?
Odgovor
photosynthesis
Kartica 296
Pitanje
Which term describes the principal green photosynthetic pigment?
Odgovor
chlorophyll
Kartica 297
Pitanje
Which term describes a graph of pigment absorption versus wavelength?
Odgovor
an absorption spectrum
Kartica 298
Pitanje
Which term describes a graph of photosynthetic effectiveness versus wavelength?
Odgovor
an action spectrum
Kartica 299
Pitanje
What is photolysis of water?
Odgovor
Light-driven splitting of water that supplies electrons and hydrogen ions and releases oxygen.
Kartica 300
Pitanje
What are light-dependent reactions?
Odgovor
Photosynthetic reactions that use light to generate ATP and reduced electron carriers while releasing oxygen.
Kartica 301
Pitanje
What is the Calvin cycle?
Odgovor
A set of chloroplast reactions that uses ATP and reduced electron carriers to convert carbon dioxide into carbohydrate precursors.
Kartica 302
Pitanje
What is carbon fixation?
Odgovor
Incorporation of inorganic carbon dioxide into an organic molecule.
Kartica 303
Pitanje
Which term describes light-driven splitting of water?
Odgovor
photolysis of water
Kartica 304
Pitanje
Which term describes photosynthetic reactions that directly capture light energy?
Odgovor
light-dependent reactions
Kartica 305
Pitanje
Which term describes the carbon-reduction cycle of photosynthesis?
Odgovor
the Calvin cycle
Kartica 306
Pitanje
Which term describes incorporation of carbon dioxide into organic matter?
Odgovor
carbon fixation
Kartica 307
Pitanje
What is the role of a stoma in photosynthesis?
Odgovor
A pore in the leaf epidermis that regulates carbon-dioxide entry as well as water loss.
Kartica 308
Pitanje
What is a limiting factor of photosynthesis?
Odgovor
The environmental factor whose availability currently restricts the photosynthetic rate.
Kartica 309
Pitanje
What is the light compensation point?
Odgovor
The light intensity at which photosynthetic carbon uptake equals respiratory carbon release.
Kartica 310
Pitanje
What is the overall word equation for oxygenic photosynthesis?
Odgovor
Carbon dioxide + water → carbohydrate + oxygen, using light energy.
Kartica 311
Pitanje
Which term describes the regulated leaf pore controlling carbon-dioxide entry for photosynthesis?
Odgovor
a stoma
Kartica 312
Pitanje
Which term describes the factor currently restricting photosynthetic rate?
Odgovor
a limiting factor
Kartica 313
Pitanje
Which term describes the light level where photosynthesis and respiration balance?
Odgovor
the light compensation point
Kartica 314
Pitanje
Where do the main stages of photosynthesis occur in a chloroplast?
Odgovor
Light-dependent reactions occur in thylakoid membranes; carbon-fixation reactions occur in the stroma.
Kartica 315
Pitanje
What energy conversion occurs during photosynthesis?
Odgovor
Light energy is converted into chemical energy stored first in ATP and reduced carriers and ultimately in organic molecules.
Kartica 316
Pitanje
From which reactant does the oxygen released by photosynthesis originate?
Odgovor
Water.
Kartica 317
Pitanje
What role does RuBisCO play in photosynthesis?
Odgovor
It catalyzes fixation of carbon dioxide by adding it to an organic acceptor molecule.
Kartica 318
Pitanje
What tradeoff is controlled when stomata open?
Odgovor
Opening permits carbon dioxide entry but increases water loss by transpiration.
Kartica 319
Pitanje
Name three leaf features that support photosynthesis.
Odgovor
A broad surface captures light, a thin structure shortens diffusion paths, and veins supply water and remove sugars; chloroplast-rich cells and stomata also help.
Kartica 320
Pitanje
What can a plant do with carbohydrate made by photosynthesis?
Odgovor
Use it in respiration, convert it to storage or structural carbohydrates, or use its carbon to make lipids, amino acids, and other molecules.
Kartica 321
Pitanje
How are products of the light-dependent reactions used in carbon fixation?
Odgovor
ATP supplies energy and NADPH supplies reducing power for conversion of fixed carbon into carbohydrate precursors.
Kartica 322
Pitanje
Why does increasing light intensity eventually stop increasing photosynthetic rate?
Odgovor
Another factor, such as carbon dioxide supply, temperature, or biochemical capacity, becomes limiting.
Kartica 323
Pitanje
How can increasing carbon dioxide concentration affect photosynthetic rate?
Odgovor
It can increase the rate until another factor becomes limiting.
Kartica 324
Pitanje
Why does photosynthetic rate usually have a temperature optimum?
Odgovor
Enzyme-controlled reactions accelerate with temperature up to an optimum, then decline as enzymes and membranes lose effective function.
Kartica 325
Pitanje
Why does an action spectrum broadly resemble the combined absorption spectra of photosynthetic pigments?
Odgovor
Wavelengths absorbed by the pigments supply more energy for photosynthesis than poorly absorbed wavelengths.
Kartica 326
Pitanje
What is semiconservative replication?
Odgovor
DNA replication in which each daughter molecule contains one parental strand and one newly synthesized strand.
Kartica 327
Pitanje
What is DNA helicase?
Odgovor
An enzyme that unwinds the double helix and separates the strands by disrupting base pairing.
Kartica 328
Pitanje
What is DNA polymerase?
Odgovor
An enzyme that adds nucleotides to a growing DNA strand using a template.
Kartica 329
Pitanje
What is a primer?
Odgovor
A short nucleic-acid segment providing a free 3′ end from which DNA polymerase can extend.
Kartica 330
Pitanje
Which term describes replication producing one old and one new strand per DNA molecule?
Odgovor
semiconservative replication
Kartica 331
Pitanje
Which term describes the enzyme that separates DNA strands?
Odgovor
DNA helicase
Kartica 332
Pitanje
Which term describes the enzyme that builds DNA from a template?
Odgovor
DNA polymerase
Kartica 333
Pitanje
Which term describes the short segment providing a starting 3′ end?
Odgovor
a primer
Kartica 334
Pitanje
What is the leading strand?
Odgovor
The new DNA strand synthesized continuously toward the replication fork.
Kartica 335
Pitanje
What is the lagging strand?
Odgovor
The new DNA strand synthesized discontinuously away from the replication fork.
Kartica 336
Pitanje
What is an Okazaki fragment?
Odgovor
A short DNA segment synthesized on the lagging strand.
Kartica 337
Pitanje
What is DNA ligase?
Odgovor
An enzyme that seals breaks in the sugar-phosphate backbone, joining DNA fragments.
Kartica 338
Pitanje
Which term describes the continuously synthesized daughter strand?
Odgovor
the leading strand
Kartica 339
Pitanje
Which term describes the discontinuously synthesized daughter strand?
Odgovor
the lagging strand
Kartica 340
Pitanje
Which term describes a short newly made segment of lagging-strand DNA?
Odgovor
an Okazaki fragment
Kartica 341
Pitanje
Which term describes the enzyme that joins DNA fragments by sealing the backbone?
Odgovor
DNA ligase
Kartica 342
Pitanje
How does complementary base pairing ensure accurate DNA copying?
Odgovor
Each template base specifies the nucleotide added opposite it: A pairs with T, and C pairs with G.
Kartica 343
Pitanje
Why does DNA polymerase synthesize DNA only 5′ to 3′?
Odgovor
It can add a nucleotide only to the free 3′ hydroxyl group of the growing strand.
Kartica 344
Pitanje
When in the cell cycle is nuclear DNA replicated?
Odgovor
During S phase of interphase, before cell division.
Kartica 345
Pitanje
How can a replication error become a permanent mutation?
Odgovor
If it escapes proofreading and repair, the altered sequence can be copied in later cell generations.
Kartica 346
Pitanje
Why are leading and lagging strands synthesized differently?
Odgovor
The templates are antiparallel while DNA polymerase works only 5′ to 3′, forcing one strand to be made discontinuously.
Kartica 347
Pitanje
How do proofreading and repair reduce replication errors?
Odgovor
Incorrectly paired nucleotides are recognized, removed, and replaced before or after replication continues.
Kartica 348
Pitanje
What three repeating steps amplify DNA in PCR?
Odgovor
Strand separation by heating, primer annealing during cooling, and DNA extension by a heat-stable polymerase.
Kartica 349
Pitanje
What determines which DNA region PCR amplifies?
Odgovor
The sequences and positions of the two primers flanking the target region.
Kartica 350
Pitanje
What is transcription?
Odgovor
Synthesis of RNA from a DNA template.
Kartica 351
Pitanje
What is RNA polymerase?
Odgovor
The enzyme that synthesizes RNA complementary to a DNA template strand.
Kartica 352
Pitanje
What is messenger RNA?
Odgovor
RNA carrying a coding sequence from DNA to ribosomes.
Kartica 353
Pitanje
What is a codon?
Odgovor
A three-base sequence in mRNA that specifies an amino acid or a translation signal.
Kartica 354
Pitanje
Which term describes RNA synthesis from DNA?
Odgovor
transcription
Kartica 355
Pitanje
Which term describes the enzyme that builds RNA from a DNA template?
Odgovor
RNA polymerase
Kartica 356
Pitanje
Which term describes RNA that carries coding information to ribosomes?
Odgovor
messenger RNA
Kartica 357
Pitanje
Which term describes a three-base mRNA unit?
Odgovor
a codon
Kartica 358
Pitanje
What is translation?
Odgovor
Synthesis of a polypeptide using the codon sequence of mRNA.
Kartica 359
Pitanje
What does a ribosome do during translation?
Odgovor
It reads mRNA and catalyzes polypeptide synthesis using its rRNA-protein machinery.
Kartica 360
Pitanje
What is transfer RNA?
Odgovor
RNA that carries a specific amino acid and pairs its anticodon with an mRNA codon.
Kartica 361
Pitanje
What is an anticodon?
Odgovor
A three-base tRNA sequence complementary to an mRNA codon.
Kartica 362
Pitanje
Which term describes polypeptide synthesis from an mRNA sequence?
Odgovor
translation
Kartica 363
Pitanje
Which term describes the translation complex that reads mRNA and builds a polypeptide?
Odgovor
a ribosome
Kartica 364
Pitanje
Which term describes the adaptor RNA carrying an amino acid?
Odgovor
transfer RNA
Kartica 365
Pitanje
Which term describes the tRNA triplet that pairs with a codon?
Odgovor
an anticodon
Kartica 366
Pitanje
What is the genetic code?
Odgovor
The set of rules relating mRNA codons to amino acids and translation signals.
Kartica 367
Pitanje
What are start and stop codons?
Odgovor
mRNA signals that establish the reading frame or terminate translation.
Kartica 368
Pitanje
Where do transcription and translation occur in a eukaryotic cell?
Odgovor
Transcription occurs in the nucleus; translation occurs on ribosomes in the cytoplasm or on rough ER.
Kartica 369
Pitanje
How is an mRNA sequence related to its DNA template strand?
Odgovor
It is complementary and antiparallel, with uracil in RNA opposite adenine in DNA.
Kartica 370
Pitanje
Which term describes the codon-to-amino-acid rule set?
Odgovor
the genetic code
Kartica 371
Pitanje
Which term describes codons that begin or end translation?
Odgovor
start and stop codons
Kartica 372
Pitanje
What reaction does the ribosome catalyze as a polypeptide grows?
Odgovor
Formation of peptide bonds between adjacent amino acids.
Kartica 373
Pitanje
What does it mean that the genetic code is degenerate?
Odgovor
Most amino acids are specified by more than one codon.
Kartica 374
Pitanje
How can one mRNA produce many polypeptides quickly?
Odgovor
Multiple ribosomes can translate the same mRNA simultaneously as a polyribosome.
Kartica 375
Pitanje
Why is translation not the final step in producing many functional proteins?
Odgovor
The polypeptide must fold and may undergo cleavage, chemical modification, or assembly with other subunits.
Kartica 376
Pitanje
How does mRNA compare with the DNA coding strand?
Odgovor
It has the same base sequence except that RNA contains uracil where DNA contains thymine.
Kartica 377
Pitanje
What happens during eukaryotic RNA splicing?
Odgovor
Introns are removed and exons are joined to form mature mRNA.
Kartica 378
Pitanje
Why must codons be read in the correct reading frame?
Odgovor
Changing the starting position changes every downstream triplet and therefore the amino-acid sequence.
Kartica 379
Pitanje
How is the correct amino acid matched to each mRNA codon?
Odgovor
Each tRNA is charged with a particular amino acid, and its anticodon pairs with the complementary codon.
Kartica 380
Pitanje
How can a base substitution affect a protein?
Odgovor
It may be silent, change one amino acid, create a stop codon, or sometimes alter RNA processing.
Kartica 381
Pitanje
What is a mutation?
Odgovor
A change in a DNA sequence or chromosome structure that can be passed to daughter cells.
Kartica 382
Pitanje
What is a base substitution?
Odgovor
Replacement of one nucleotide pair by another.
Kartica 383
Pitanje
What is an insertion mutation?
Odgovor
Addition of one or more nucleotides to a DNA sequence.
Kartica 384
Pitanje
What is a deletion mutation?
Odgovor
Loss of one or more nucleotides from a DNA sequence.
Kartica 385
Pitanje
Which term describes a lasting DNA-sequence or chromosome change?
Odgovor
a mutation
Kartica 386
Pitanje
Which term describes replacement of one DNA base pair?
Odgovor
a base substitution
Kartica 387
Pitanje
Which term describes addition of nucleotides to DNA?
Odgovor
an insertion mutation
Kartica 388
Pitanje
Which term describes loss of nucleotides from DNA?
Odgovor
a deletion mutation
Kartica 389
Pitanje
What is a frameshift mutation?
Odgovor
A coding-sequence insertion or deletion not divisible by three that changes downstream codon grouping.
Kartica 390
Pitanje
What is a silent mutation?
Odgovor
A sequence change that does not alter the encoded amino acid.
Kartica 391
Pitanje
What is a missense mutation?
Odgovor
A mutation that changes a codon so a different amino acid is incorporated.
Kartica 392
Pitanje
What is a nonsense mutation?
Odgovor
A mutation that changes an amino-acid codon into a stop codon.
Kartica 393
Pitanje
Which term describes a mutation that shifts downstream codon grouping?
Odgovor
a frameshift mutation
Kartica 394
Pitanje
Which term describes a coding change that leaves the amino acid unchanged?
Odgovor
a silent mutation
Kartica 395
Pitanje
Which term describes a mutation causing one amino-acid substitution?
Odgovor
a missense mutation
Kartica 396
Pitanje
Which term describes a mutation creating a premature stop codon?
Odgovor
a nonsense mutation
Kartica 397
Pitanje
How do germline and somatic mutations differ in inheritance?
Odgovor
Germline mutations can enter gametes and be inherited; somatic mutations affect a cell lineage within the individual.
Kartica 398
Pitanje
What can cause mutations?
Odgovor
Replication errors, spontaneous chemical changes, radiation, and mutagenic chemicals can alter DNA.
Kartica 399
Pitanje
How does DNA repair protect genome stability?
Odgovor
Repair systems detect damaged or mismatched DNA and restore the correct structure or sequence when possible.
Kartica 400
Pitanje
Why are mutations essential to evolution despite often being neutral or harmful?
Odgovor
They create new alleles, providing the heritable variation on which selection and drift act.
Kartica 401
Pitanje
What is the basic role of guide RNA in CRISPR gene editing?
Odgovor
It directs a nuclease to a complementary DNA sequence.
Kartica 402
Pitanje
Why can the same type of DNA mutation have effects ranging from none to severe?
Odgovor
Effects depend on location, genetic-code redundancy, protein role, cell type, and environmental context.
Kartica 403
Pitanje
How can accumulated mutations contribute to cancer?
Odgovor
Mutations can activate growth-promoting genes or disable genes that restrain division, repair DNA, or trigger cell death.
Kartica 404
Pitanje
Why can repairing a CRISPR-induced DNA break produce different editing outcomes?
Odgovor
Different cellular repair pathways may disrupt the target sequence or use a supplied template for a specific change.
Kartica 405
Pitanje
What is an off-target effect in gene editing?
Odgovor
An unintended DNA change at a site sufficiently similar to the intended target.
Kartica 406
Pitanje
Why does heritable human genome editing raise additional ethical concerns?
Odgovor
Changes could pass to future generations who cannot consent, with uncertain long-term biological and social effects.
Kartica 407
Pitanje
What is the cell cycle?
Odgovor
The ordered sequence of cell growth, DNA replication, nuclear division, and cell division.
Kartica 408
Pitanje
What is interphase?
Odgovor
The period of growth, normal activity, and DNA replication between nuclear divisions.
Kartica 409
Pitanje
What is mitosis?
Odgovor
Nuclear division that usually produces genetically equivalent daughter nuclei.
Kartica 410
Pitanje
What is cytokinesis?
Odgovor
Division of the cytoplasm to form separate daughter cells.
Kartica 411
Pitanje
Which term describes the ordered sequence from one cell division to the next?
Odgovor
the cell cycle
Kartica 412
Pitanje
Which term describes the growth and DNA-replication period between divisions?
Odgovor
interphase
Kartica 413
Pitanje
Which term describes division producing genetically equivalent nuclei?
Odgovor
mitosis
Kartica 414
Pitanje
Which term describes physical division of the cytoplasm?
Odgovor
cytokinesis
Kartica 415
Pitanje
What is a chromosome?
Odgovor
One DNA molecule packaged with associated proteins.
Kartica 416
Pitanje
What are sister chromatids?
Odgovor
The two replicated copies of a chromosome joined before separation.
Kartica 417
Pitanje
What is a centromere?
Odgovor
The chromosome region that holds sister chromatids together and organizes kinetochore attachment.
Kartica 418
Pitanje
What is the mitotic spindle?
Odgovor
A microtubule system that attaches to and separates chromosomes during cell division.
Kartica 419
Pitanje
Which term describes a protein-packaged DNA molecule?
Odgovor
a chromosome
Kartica 420
Pitanje
Which term describes joined replicated copies of one chromosome?
Odgovor
sister chromatids
Kartica 421
Pitanje
Which term describes the chromosome region joining sister chromatids?
Odgovor
a centromere
Kartica 422
Pitanje
Which term describes the chromosome-separating microtubule system?
Odgovor
the mitotic spindle
Kartica 423
Pitanje
What is the basic sequence of mitosis?
Odgovor
Chromosomes condense, align at the cell equator, sister chromatids separate to opposite poles, and new nuclei form.
Kartica 424
Pitanje
Why must DNA replicate before mitosis?
Odgovor
Each chromosome must have two copies so each daughter nucleus can receive a complete genome.
Kartica 425
Pitanje
Why are daughter cells from mitosis usually genetically similar?
Odgovor
Replicated sister chromatids are separated so each daughter receives one copy of every chromosome.
Kartica 426
Pitanje
What are major roles of mitosis in multicellular organisms?
Odgovor
Growth, tissue repair, cell replacement, and some forms of asexual reproduction.
Kartica 427
Pitanje
How do homologous chromosomes differ from sister chromatids?
Odgovor
Homologs carry the same gene loci but may have different alleles; sister chromatids are replicated copies of one chromosome.
Kartica 428
Pitanje
What key outcome distinguishes mitosis from meiosis?
Odgovor
Mitosis usually preserves chromosome number and similarity; meiosis halves chromosome number and generates genetically varied haploid cells.
Kartica 429
Pitanje
How does cytokinesis commonly occur in animal cells?
Odgovor
A contractile ring tightens the plasma membrane into a cleavage furrow.
Kartica 430
Pitanje
How does cytokinesis commonly occur in plant cells?
Odgovor
Vesicles fuse at the center to form a cell plate that develops into new membranes and a cell wall.
Kartica 431
Pitanje
What is the purpose of cell-cycle checkpoints?
Odgovor
They delay progression when conditions are unsuitable or DNA and chromosome attachment are defective.
Kartica 432
Pitanje
How is loss of cell-cycle control related to cancer?
Odgovor
Cells can divide despite damage or growth restraints, producing an expanding abnormal clone.
Kartica 433
Pitanje
What is a gene?
Odgovor
A DNA sequence that contributes to a functional product and influences a characteristic or cellular process.
Kartica 434
Pitanje
What is an allele?
Odgovor
One of the alternative DNA-sequence forms at a gene locus.
Kartica 435
Pitanje
What is a gene locus?
Odgovor
The physical position of a gene on a chromosome.
Kartica 436
Pitanje
What is a genotype?
Odgovor
The allele combination of an organism at one or more loci.
Kartica 437
Pitanje
Which term describes a functional DNA sequence?
Odgovor
a gene
Kartica 438
Pitanje
Which term describes an alternative form of a gene?
Odgovor
an allele
Kartica 439
Pitanje
Which term describes a gene's chromosome position?
Odgovor
a gene locus
Kartica 440
Pitanje
Which term describes an organism's allele combination?
Odgovor
a genotype
Kartica 441
Pitanje
What is a phenotype?
Odgovor
An observable or measurable trait produced by genotype and environment.
Kartica 442
Pitanje
What is homozygous?
Odgovor
Having two identical alleles at a diploid locus.
Kartica 443
Pitanje
What is heterozygous?
Odgovor
Having two different alleles at a diploid locus.
Kartica 444
Pitanje
What is a dominant allele?
Odgovor
An allele expressed in the phenotype of a heterozygote under a specified inheritance model.
Kartica 445
Pitanje
Which term describes an observable trait resulting from genes and environment?
Odgovor
a phenotype
Kartica 446
Pitanje
Which term describes having two identical alleles at a locus?
Odgovor
homozygous
Kartica 447
Pitanje
Which term describes having two different alleles at a locus?
Odgovor
heterozygous
Kartica 448
Pitanje
Which term describes an allele expressed in a heterozygote?
Odgovor
a dominant allele
Kartica 449
Pitanje
What is a recessive allele?
Odgovor
An allele whose phenotype is masked by a dominant allele in a heterozygote.
Kartica 450
Pitanje
What is a genetic carrier?
Odgovor
An unaffected heterozygote who can transmit a recessive disease allele.
Kartica 451
Pitanje
What is a test cross?
Odgovor
A cross with a homozygous recessive individual used to infer an unknown dominant phenotype's genotype.
Kartica 452
Pitanje
What is a pedigree?
Odgovor
A diagram showing biological relationships and occurrence of a trait across generations.
Kartica 453
Pitanje
Which term describes an allele masked in a heterozygote?
Odgovor
a recessive allele
Kartica 454
Pitanje
Which term describes an unaffected heterozygote carrying a recessive disease allele?
Odgovor
a genetic carrier
Kartica 455
Pitanje
Which term describes a cross used to reveal an unknown dominant genotype?
Odgovor
a test cross
Kartica 456
Pitanje
Which term describes a family diagram tracking a trait across generations?
Odgovor
a pedigree
Kartica 457
Pitanje
What does allele segregation mean during gamete formation?
Odgovor
The two alleles at a diploid locus separate so each gamete receives one.
Kartica 458
Pitanje
What does a Punnett square predict?
Odgovor
Expected genotype and phenotype probabilities from specified parental gametes, not guaranteed family outcomes.
Kartica 459
Pitanje
What phenotypic ratio is expected from Aa × Aa with complete dominance?
Odgovor
Approximately 3 dominant phenotype : 1 recessive phenotype.
Kartica 460
Pitanje
What genotypic ratio is expected from Aa × Aa?
Odgovor
1 AA : 2 Aa : 1 aa.
Kartica 461
Pitanje
What happens in codominance?
Odgovor
Both alleles contribute distinctly to the heterozygous phenotype.
Kartica 462
Pitanje
What happens in incomplete dominance?
Odgovor
The heterozygote has a phenotype intermediate between the two homozygotes.
Kartica 463
Pitanje
How can environment affect phenotype without changing genotype?
Odgovor
Conditions alter development, physiology, or gene expression, changing the observed trait.
Kartica 464
Pitanje
What is the ultimate source of new alleles?
Odgovor
Mutation.
Kartica 465
Pitanje
Why are X-linked recessive traits more common in XY individuals?
Odgovor
They have only one X chromosome, so one recessive allele on it can determine the phenotype.
Kartica 466
Pitanje
When is the product rule used in genetic probability?
Odgovor
For independent events that must both occur; multiply their probabilities.
Kartica 467
Pitanje
When is the sum rule used in genetic probability?
Odgovor
For mutually exclusive alternative outcomes; add their probabilities.
Kartica 468
Pitanje
Why do polygenic traits often show continuous variation?
Odgovor
Many loci contribute small effects, creating many possible genotypes and phenotypes, often further influenced by environment.
Kartica 469
Pitanje
What pedigree pattern can suggest an autosomal recessive trait?
Odgovor
Unaffected parents can have affected children, and all sexes are affected at similar frequencies.
Kartica 470
Pitanje
What is a species?
Odgovor
A group of organisms whose members can potentially interbreed and produce fertile offspring under natural conditions.
Kartica 471
Pitanje
What is binomial nomenclature?
Odgovor
The two-part scientific naming system using a genus name followed by a specific epithet.
Kartica 472
Pitanje
What is taxonomy?
Odgovor
The naming and classification of organisms.
Kartica 473
Pitanje
What is a biological domain?
Odgovor
The broadest commonly used taxonomic rank, separating Bacteria, Archaea, and Eukarya.
Kartica 474
Pitanje
Which term describes a naturally interbreeding group producing fertile offspring?
Odgovor
a species
Kartica 475
Pitanje
Which term describes the genus-plus-specific-epithet naming system?
Odgovor
binomial nomenclature
Kartica 476
Pitanje
Which term describes the science of naming and classifying organisms?
Odgovor
taxonomy
Kartica 477
Pitanje
Which term describes the broadest common taxonomic rank?
Odgovor
a biological domain
Kartica 478
Pitanje
What is biodiversity?
Odgovor
Variation of life at genetic, species, and ecosystem levels.
Kartica 479
Pitanje
What is an autotroph?
Odgovor
An organism that makes organic compounds from inorganic carbon using light or chemical energy.
Kartica 480
Pitanje
What is a heterotroph?
Odgovor
An organism that obtains organic carbon by consuming other organisms or their products.
960 kartica
IB Biology SL Flashcards: Complete Course Review
Učite iz ovog špila besplatnoNibomo se otvara kako biste mogli početi učiti.
Kartica 481
Pitanje
What is a unicellular organism?
Odgovor
An organism consisting of one cell that carries out all essential life functions.
Kartica 482
Pitanje
Which term describes variation of life across genes, species, and ecosystems?
Odgovor
biodiversity
Kartica 483
Pitanje
Which term describes an organism that builds organic matter from inorganic carbon?
Odgovor
an autotroph
Kartica 484
Pitanje
Which term describes an organism obtaining organic carbon from other organisms?
Odgovor
a heterotroph
Kartica 485
Pitanje
Which term describes an organism made of one cell?
Odgovor
a unicellular organism
Kartica 486
Pitanje
What is a multicellular organism?
Odgovor
An organism composed of many cooperating cells, often with specialized cell types.
Kartica 487
Pitanje
What is a karyotype?
Odgovor
An ordered display of chromosomes used to examine their number and large-scale structure.
Kartica 488
Pitanje
What broad feature distinguishes both Bacteria and Archaea from Eukarya?
Odgovor
Their cells lack a nucleus and other membrane-bound organelles.
Kartica 489
Pitanje
What features characterize most plant cells?
Odgovor
Cellulose walls, chloroplasts in photosynthetic tissues, and large vacuoles are typical features.
Kartica 490
Pitanje
Which term describes an organism made of many cooperating cells?
Odgovor
a multicellular organism
Kartica 491
Pitanje
Which term describes an ordered display of an individual's chromosomes?
Odgovor
a karyotype
Kartica 492
Pitanje
How do fungi obtain nutrients?
Odgovor
They secrete digestive enzymes and absorb soluble products; their cells usually have chitin-containing walls.
Kartica 493
Pitanje
What distinguishes animal nutrition and cell structure?
Odgovor
Animals ingest organic material, and their cells lack cell walls and chloroplasts.
Kartica 494
Pitanje
Why are scientific names useful across languages?
Odgovor
A standardized name identifies the same organism internationally and reduces ambiguity from local common names.
Kartica 495
Pitanje
Why can genetic diversity improve a population's resilience?
Odgovor
More heritable variation increases the chance that some individuals tolerate new diseases or environmental changes.
Kartica 496
Pitanje
What does ecosystem diversity measure?
Odgovor
The variety of habitats, communities, and ecological processes within a region.
Kartica 497
Pitanje
Why are Archaea classified separately from Bacteria?
Odgovor
They differ in genetic sequences, membrane chemistry, cell-wall composition, and aspects of molecular machinery.
Kartica 498
Pitanje
Why is the biological species concept difficult to apply to fossils or asexual organisms?
Odgovor
Their ability to interbreed and produce fertile offspring cannot be tested in the usual way.
Kartica 499
Pitanje
Does a larger chromosome number necessarily mean a more complex organism?
Odgovor
No. Chromosome number varies through fusion, fission, and duplication and does not directly measure biological complexity.
Kartica 500
Pitanje
Does genome size reliably predict organismal complexity?
Odgovor
No. Large amounts of noncoding and repeated DNA make genome size a poor simple measure of complexity.
Kartica 501
Pitanje
What evidence can be combined when classifying organisms?
Odgovor
Molecular sequences, cell structure, anatomy, development, physiology, and reproductive evidence can all contribute.
Kartica 502
Pitanje
What is gas exchange?
Odgovor
Diffusion of respiratory gases between an organism and its environment or transport fluid.
Kartica 503
Pitanje
What is ventilation?
Odgovor
Bulk movement of air or water over a gas-exchange surface.
Kartica 504
Pitanje
What is an alveolus?
Odgovor
A microscopic air sac in the lung where gases diffuse between air and blood.
Kartica 505
Pitanje
What is pulmonary surfactant?
Odgovor
A substance lining alveoli that lowers surface tension and reduces collapse.
Kartica 506
Pitanje
Which term describes diffusion of oxygen and carbon dioxide across a respiratory surface?
Odgovor
gas exchange
Kartica 507
Pitanje
Which term describes bulk movement of respiratory medium over an exchange surface?
Odgovor
ventilation
Kartica 508
Pitanje
Which term describes a microscopic lung air sac?
Odgovor
an alveolus
Kartica 509
Pitanje
Which term describes the alveolar lining that lowers surface tension?
Odgovor
pulmonary surfactant
Kartica 510
Pitanje
What is the diaphragm?
Odgovor
A sheet of skeletal muscle whose contraction increases thoracic volume during inhalation.
Kartica 511
Pitanje
What is tidal volume?
Odgovor
The volume of air moved in or out during a normal breath.
Kartica 512
Pitanje
What is a stoma?
Odgovor
A regulated epidermal pore through which gases diffuse in leaves.
Kartica 513
Pitanje
What is countercurrent exchange?
Odgovor
Exchange between fluids moving in opposite directions, maintaining a gradient along most of the surface.
Kartica 514
Pitanje
Which term describes the muscle sheet that expands the thorax during inhalation?
Odgovor
the diaphragm
Kartica 515
Pitanje
Which term describes air volume moved in one normal breath?
Odgovor
tidal volume
Kartica 516
Pitanje
Which term describes a regulated leaf gas-exchange pore?
Odgovor
a stoma
Kartica 517
Pitanje
Which term describes opposite fluid flow that maintains an exchange gradient?
Odgovor
countercurrent exchange
Kartica 518
Pitanje
What features make an efficient gas-exchange surface?
Odgovor
Large area, short diffusion distance, permeability, and maintained concentration gradients.
Kartica 519
Pitanje
How is a steep oxygen gradient maintained across alveoli?
Odgovor
Ventilation replenishes alveolar oxygen and blood flow removes absorbed oxygen.
Kartica 520
Pitanje
How does diaphragm contraction cause inhalation?
Odgovor
Thoracic volume increases, lung pressure falls below atmospheric pressure, and air flows inward.
Kartica 521
Pitanje
What drives quiet exhalation?
Odgovor
The diaphragm relaxes and elastic recoil reduces thoracic and lung volume, raising pressure and pushing air out.
Kartica 522
Pitanje
Why do ventilation rate and depth increase during exercise?
Odgovor
They increase oxygen uptake and carbon dioxide removal to support higher cellular respiration.
Kartica 523
Pitanje
How does leaf structure shorten the pathway for carbon dioxide diffusion?
Odgovor
Stomata open into air spaces, and mesophyll cells expose moist surfaces close to those spaces.
Kartica 524
Pitanje
Why does carbon dioxide diffuse from tissues into blood?
Odgovor
Respiring cells produce carbon dioxide, making its partial pressure higher in tissues than in incoming blood.
Kartica 525
Pitanje
How does countercurrent flow improve oxygen uptake at fish gills?
Odgovor
Blood continually meets water with a higher oxygen concentration, preserving diffusion along the lamella.
Kartica 526
Pitanje
Why does closing stomata reduce both water loss and photosynthesis?
Odgovor
It limits water-vapor diffusion out but also restricts carbon dioxide diffusion into the leaf.
Kartica 527
Pitanje
What is a circulatory system?
Odgovor
A transport system that moves a fluid carrying gases, nutrients, wastes, hormones, and heat through an organism.
Kartica 528
Pitanje
What is an artery?
Odgovor
A blood vessel carrying blood away from the heart under relatively high pressure.
Kartica 529
Pitanje
What is a vein?
Odgovor
A blood vessel carrying blood toward the heart, usually with low pressure and often valves.
Kartica 530
Pitanje
What is a capillary?
Odgovor
A microscopic thin-walled vessel where substances exchange between blood and tissues.
Kartica 531
Pitanje
Which term describes an internal fluid-transport system?
Odgovor
a circulatory system
Kartica 532
Pitanje
Which term describes a vessel carrying blood away from the heart?
Odgovor
an artery
Kartica 533
Pitanje
Which term describes a vessel carrying blood toward the heart?
Odgovor
a vein
Kartica 534
Pitanje
Which term describes a microscopic exchange blood vessel?
Odgovor
a capillary
Kartica 535
Pitanje
What is the cardiac cycle?
Odgovor
The repeating sequence of heart-chamber contraction and relaxation that pumps blood.
Kartica 536
Pitanje
What is hemoglobin?
Odgovor
An iron-containing protein in red blood cells that binds oxygen reversibly.
Kartica 537
Pitanje
What is xylem?
Odgovor
Plant vascular tissue that transports water and mineral ions and provides structural support.
Kartica 538
Pitanje
What is phloem?
Odgovor
Plant vascular tissue that transports sucrose and other organic solutes between sources and sinks.
Kartica 539
Pitanje
Which term describes the repeating pumping sequence of the heart?
Odgovor
the cardiac cycle
Kartica 540
Pitanje
Which term describes the oxygen-carrying protein of red blood cells?
Odgovor
hemoglobin
Kartica 541
Pitanje
Which term describes plant tissue carrying water and minerals?
Odgovor
xylem
Kartica 542
Pitanje
Which term describes plant tissue carrying organic solutes?
Odgovor
phloem
Kartica 543
Pitanje
What is transpiration?
Odgovor
Loss of water vapor from plant surfaces, mainly through stomata.
Kartica 544
Pitanje
What is phloem translocation?
Odgovor
Movement of organic solutes through phloem from sources to sinks.
Kartica 545
Pitanje
How do a source and a sink differ in plant transport?
Odgovor
A source releases assimilates to phloem; a sink removes them for use or storage.
Kartica 546
Pitanje
What makes human circulation a double circulation?
Odgovor
Blood passes through the heart once in the pulmonary circuit and again in the systemic circuit during one complete journey.
Kartica 547
Pitanje
Which term describes water-vapor loss from plant surfaces?
Odgovor
transpiration
Kartica 548
Pitanje
Which term describes movement of organic solutes through phloem?
Odgovor
phloem translocation
Kartica 549
Pitanje
Which term describes the exporting and importing regions of phloem transport?
Odgovor
source and sink
Kartica 550
Pitanje
How is an artery adapted to high pressure?
Odgovor
It has thick elastic and muscular walls and a relatively narrow lumen.
Kartica 551
Pitanje
How is a vein adapted to return low-pressure blood?
Odgovor
It has a wide lumen, thinner walls, and valves that reduce backflow.
Kartica 552
Pitanje
How does capillary structure support exchange?
Odgovor
One-cell-thick walls give a short diffusion distance; extensive branching gives a large total area; narrow lumens slow flow and keep blood close to tissues.
Kartica 553
Pitanje
What determines whether a heart valve opens or closes?
Odgovor
Pressure differences across the valve.
Kartica 554
Pitanje
Trace water from soil to the atmosphere through a plant.
Odgovor
Soil → root hairs → root tissues → xylem → leaf mesophyll → leaf air spaces → stomata → atmosphere.
Kartica 555
Pitanje
Why may root cells use active transport to absorb mineral ions?
Odgovor
Ion concentrations can be lower in soil than in root cells, so uptake must occur against a gradient.
Kartica 556
Pitanje
Why do large multicellular organisms need bulk transport systems?
Odgovor
Their low surface-area-to-volume ratio and long diffusion distances make diffusion alone too slow for whole-body supply.
Kartica 557
Pitanje
Why does hemoglobin unload more oxygen in actively respiring tissues?
Odgovor
Lower oxygen and often higher carbon dioxide and acidity reduce hemoglobin's oxygen affinity.
Kartica 558
Pitanje
How does transpiration pull water upward through xylem?
Odgovor
Evaporation lowers leaf water potential and creates tension; cohesion transmits the pull through the continuous water column.
Kartica 559
Pitanje
How do wind and low humidity generally affect transpiration?
Odgovor
Both maintain a steep water-vapor gradient outside the leaf, increasing transpiration if stomata remain open.
Kartica 560
Pitanje
What drives mass flow in phloem?
Odgovor
Sugar loading draws in water and raises pressure at a source; unloading lowers pressure at a sink, producing bulk flow.
Kartica 561
Pitanje
Can the same plant organ be a source at one time and a sink at another?
Odgovor
Yes. A storage organ may import sugars while filling and export them later during growth or germination.
Kartica 562
Pitanje
What is a neuron?
Odgovor
An excitable cell specialized to receive, process, and transmit information.
Kartica 563
Pitanje
What is a sensory neuron?
Odgovor
A neuron carrying information from a receptor toward the central nervous system.
Kartica 564
Pitanje
What is a motor neuron?
Odgovor
A neuron carrying commands from the central nervous system to an effector.
Kartica 565
Pitanje
What is the resting potential?
Odgovor
The voltage difference across an unstimulated neuron's membrane, with the inside negative relative to outside.
Kartica 566
Pitanje
Which term describes an excitable information-transmitting cell?
Odgovor
a neuron
Kartica 567
Pitanje
Which term describes a neuron carrying receptor information to the CNS?
Odgovor
a sensory neuron
Kartica 568
Pitanje
Which term describes a neuron carrying CNS commands to an effector?
Odgovor
a motor neuron
Kartica 569
Pitanje
Which term describes the negative-inside voltage of an unstimulated neuron?
Odgovor
the resting potential
Kartica 570
Pitanje
What is an action potential?
Odgovor
A brief, self-propagating reversal and restoration of membrane potential along an excitable membrane.
Kartica 571
Pitanje
What is depolarization?
Odgovor
A change that makes membrane potential less negative, and during an action potential often positive.
Kartica 572
Pitanje
What is repolarization?
Odgovor
Return of membrane potential toward its resting negative value after depolarization.
Kartica 573
Pitanje
What is a synapse?
Odgovor
A junction where one cell communicates with another cell.
Kartica 574
Pitanje
Which term describes a brief propagating change in neuron membrane voltage?
Odgovor
an action potential
Kartica 575
Pitanje
Which term describes a membrane-voltage change toward a less negative value?
Odgovor
depolarization
Kartica 576
Pitanje
Which term describes return toward resting membrane voltage?
Odgovor
repolarization
Kartica 577
Pitanje
Which term describes a communication junction between cells?
Odgovor
a synapse
Kartica 578
Pitanje
What is a neurotransmitter?
Odgovor
A chemical released by a neuron that changes the activity of a target cell.
Kartica 579
Pitanje
What is the refractory period?
Odgovor
A brief period after an action potential when another is impossible or requires a stronger stimulus.
Kartica 580
Pitanje
What is myelin?
Odgovor
An insulating sheath around some axons that speeds impulse conduction.
Kartica 581
Pitanje
What happens when membrane depolarization reaches threshold?
Odgovor
Voltage-gated channels trigger the self-amplifying events of an action potential.
Kartica 582
Pitanje
Which term describes a neuron-released signaling chemical?
Odgovor
a neurotransmitter
Kartica 583
Pitanje
Which term describes the recovery interval after an action potential?
Odgovor
the refractory period
Kartica 584
Pitanje
Which term describes the insulating axon sheath?
Odgovor
myelin
Kartica 585
Pitanje
What does the all-or-none principle mean for an action potential?
Odgovor
Once threshold is reached, the action potential has a characteristic size; stronger stimuli increase frequency, not its amplitude.
Kartica 586
Pitanje
How does myelin increase conduction speed?
Odgovor
Depolarizing current travels rapidly beneath myelin and action potentials regenerate mainly at gaps in the sheath.
Kartica 587
Pitanje
What is the basic sequence at a chemical synapse?
Odgovor
An impulse triggers neurotransmitter release; it diffuses across the cleft, binds receptors, and alters the postsynaptic cell.
Kartica 588
Pitanje
Why can a reflex response be rapid?
Odgovor
A short neural pathway produces an automatic response without waiting for conscious processing.
Kartica 589
Pitanje
What is sensory transduction?
Odgovor
Conversion of a physical or chemical stimulus into an electrical signal in a receptor cell.
Kartica 590
Pitanje
How does an action potential propagate along an axon?
Odgovor
Local current depolarizes the next membrane region to threshold, opening voltage-gated channels there.
Kartica 591
Pitanje
Why does an action potential normally travel in one direction along an axon?
Odgovor
The membrane just behind it is refractory and cannot immediately fire again.
Kartica 592
Pitanje
How is neurotransmitter action ended?
Odgovor
The transmitter is removed by enzymatic breakdown, reuptake, or diffusion away.
Kartica 593
Pitanje
What is sensory adaptation?
Odgovor
Reduced receptor or neural response during a constant, unchanging stimulus.
Kartica 594
Pitanje
How can a drug alter synaptic transmission?
Odgovor
It may mimic or block a transmitter, change its release, or change its removal from the synaptic cleft.
Kartica 595
Pitanje
What is an organ system?
Odgovor
A group of organs coordinating to perform major functions for an organism.
Kartica 596
Pitanje
What is a hormone?
Odgovor
A signaling molecule released into transport fluid and acting on target cells with suitable receptors.
Kartica 597
Pitanje
What is an endocrine gland?
Odgovor
A gland that secretes hormones into extracellular fluid and blood rather than through a duct.
Kartica 598
Pitanje
What is a hormone target cell?
Odgovor
A cell able to respond because it has the appropriate receptor.
Kartica 599
Pitanje
Which term describes a coordinated group of organs?
Odgovor
an organ system
Kartica 600
Pitanje
Which term describes a long-distance chemical messenger carried in body fluid?
Odgovor
a hormone
Kartica 601
Pitanje
Which term describes a ductless hormone-secreting gland?
Odgovor
an endocrine gland
Kartica 602
Pitanje
Which term describes a cell with a receptor for a particular hormone?
Odgovor
a hormone target cell
Kartica 603
Pitanje
What is digestion?
Odgovor
Mechanical and chemical breakdown of food into molecules small enough to absorb.
Kartica 604
Pitanje
What is absorption?
Odgovor
Movement of digested nutrients across an exchange surface into blood or lymph.
Kartica 605
Pitanje
What is peristalsis?
Odgovor
Coordinated waves of smooth-muscle contraction that move material through the digestive tract.
Kartica 606
Pitanje
What is an intestinal villus?
Odgovor
A finger-like projection increasing the absorptive surface of the small intestine.
Kartica 607
Pitanje
Which term describes breakdown of food into absorbable molecules?
Odgovor
digestion
Kartica 608
Pitanje
Which term describes movement of digested nutrients into transport fluids?
Odgovor
absorption
Kartica 609
Pitanje
Which term describes wave-like gut contractions moving contents?
Odgovor
peristalsis
Kartica 610
Pitanje
Which term describes a finger-like intestinal absorption projection?
Odgovor
an intestinal villus
Kartica 611
Pitanje
What is excretion?
Odgovor
Removal of metabolic waste products from the body.
Kartica 612
Pitanje
What is a nephron?
Odgovor
The microscopic functional unit of the kidney that filters blood and modifies filtrate into urine.
Kartica 613
Pitanje
What is ultrafiltration?
Odgovor
Pressure-driven filtration of small molecules from blood into a kidney capsule while cells and most proteins remain in blood.
Kartica 614
Pitanje
What is selective reabsorption?
Odgovor
Recovery of useful substances and regulated amounts of water and ions from kidney filtrate into blood.
Kartica 615
Pitanje
Which term describes removal of metabolic wastes?
Odgovor
excretion
Kartica 616
Pitanje
Which term describes the kidney's microscopic functional unit?
Odgovor
a nephron
Kartica 617
Pitanje
Which term describes pressure filtration at the start of a nephron?
Odgovor
ultrafiltration
Kartica 618
Pitanje
Which term describes return of useful substances from kidney filtrate to blood?
Odgovor
selective reabsorption
Kartica 619
Pitanje
What is skeletal muscle?
Odgovor
Striated voluntary muscle attached to the skeleton and used for movement and posture.
Kartica 620
Pitanje
What is an antagonistic muscle pair?
Odgovor
Two muscles producing opposite movements at a joint because muscles pull but do not push.
Kartica 621
Pitanje
How do nervous and endocrine signaling generally differ?
Odgovor
Neural signals are rapid and targeted; hormonal signals are usually slower, longer-lasting, and distributed through body fluids.
Kartica 622
Pitanje
Why does a circulating hormone affect only some cells?
Odgovor
Only target cells express receptors that recognize the hormone and activate a response.
Kartica 623
Pitanje
Which term describes voluntary striated muscle that moves the skeleton?
Odgovor
skeletal muscle
Kartica 624
Pitanje
Which term describes two muscles producing opposite joint movements?
Odgovor
an antagonistic muscle pair
Kartica 625
Pitanje
What is the final absorbable product of most dietary carbohydrate digestion?
Odgovor
Monosaccharides, especially glucose.
Kartica 626
Pitanje
What are the main absorbable products of protein digestion?
Odgovor
Amino acids and small peptides that are completed to amino acids during absorption.
Kartica 627
Pitanje
How is the small intestine adapted for absorption?
Odgovor
Folds, villi, and microvilli increase area; a thin epithelium, rich blood supply, and lymph vessels support transport.
Kartica 628
Pitanje
Name three integrative roles of the liver.
Odgovor
It processes absorbed nutrients, regulates blood chemistry, detoxifies substances, produces bile, and converts ammonia to urea; any three are sufficient.
Kartica 629
Pitanje
Why are blood cells and most plasma proteins absent from normal kidney filtrate?
Odgovor
They are too large to cross the filtration barrier.
Kartica 630
Pitanje
How do muscles move a bone at a joint?
Odgovor
Contraction shortens the muscle, pulling through a tendon on the bone.
Kartica 631
Pitanje
Why are antagonistic muscles needed at many joints?
Odgovor
A muscle can pull in one direction but cannot push itself back, so an opposing muscle produces the reverse movement.
Kartica 632
Pitanje
Why must organ systems be integrated rather than acting independently?
Odgovor
Each system depends on materials, signals, waste removal, and stable conditions supplied by other systems.
Kartica 633
Pitanje
Why do many absorbed lipids enter lymph before blood?
Odgovor
Intestinal cells package them into lipoprotein particles too large to enter ordinary blood capillaries directly.
Kartica 634
Pitanje
Why is glucose normally absent from final urine?
Odgovor
Filtered glucose is selectively reabsorbed into blood when transporter capacity is not exceeded.
Kartica 635
Pitanje
How do respiratory, circulatory, and muscular systems cooperate during exercise?
Odgovor
Ventilation supplies oxygen, circulation transports gases and fuels, and muscles use ATP while returning carbon dioxide, heat, and metabolites.
Kartica 636
Pitanje
How do liver, circulation, and kidneys cooperate in nitrogen-waste removal?
Odgovor
The liver converts toxic ammonia to urea, blood carries urea, and kidneys filter and excrete it.
Kartica 637
Pitanje
What is a pathogen?
Odgovor
A biological agent capable of causing disease.
Kartica 638
Pitanje
What is an antigen?
Odgovor
A molecule recognized specifically by an antibody or lymphocyte receptor.
Kartica 639
Pitanje
What is innate immunity?
Odgovor
Rapid, nonspecific defense mechanisms present without prior exposure.
Kartica 640
Pitanje
What is adaptive immunity?
Odgovor
Specific defense that develops through lymphocyte activation and can form memory.
Kartica 641
Pitanje
Which term describes a disease-causing biological agent?
Odgovor
a pathogen
Kartica 642
Pitanje
Which term describes a molecule specifically recognized by adaptive immune receptors?
Odgovor
an antigen
Kartica 643
Pitanje
Which term describes rapid nonspecific immune defense?
Odgovor
innate immunity
Kartica 644
Pitanje
Which term describes specific immune defense capable of memory?
Odgovor
adaptive immunity
Kartica 645
Pitanje
What is a phagocyte?
Odgovor
A cell that engulfs and digests microbes, particles, or damaged cells.
Kartica 646
Pitanje
What is a lymphocyte?
Odgovor
An adaptive immune cell with receptors specific to particular antigens.
Kartica 647
Pitanje
What is an antibody?
Odgovor
A secreted immunoglobulin that binds a specific antigen.
Kartica 648
Pitanje
What is a B lymphocyte?
Odgovor
A lymphocyte that can differentiate into antibody-secreting plasma cells and memory cells.
Kartica 649
Pitanje
Which term describes an engulfing immune cell?
Odgovor
a phagocyte
Kartica 650
Pitanje
Which term describes an antigen-specific adaptive immune cell?
Odgovor
a lymphocyte
Kartica 651
Pitanje
Which term describes a secreted antigen-binding immunoglobulin?
Odgovor
an antibody
Kartica 652
Pitanje
Which term describes the lymphocyte lineage that produces antibody-secreting cells?
Odgovor
a B lymphocyte
Kartica 653
Pitanje
What is a helper T cell?
Odgovor
A lymphocyte that coordinates immune responses through contact signals and cytokines.
Kartica 654
Pitanje
What is an immune memory cell?
Odgovor
A long-lived lymphocyte that responds rapidly after re-exposure to its antigen.
Kartica 655
Pitanje
What is vaccination?
Odgovor
Deliberate exposure to a safe form or component of an antigen to generate protective immune memory.
Kartica 656
Pitanje
What is an antibiotic?
Odgovor
A substance that kills bacteria or inhibits their growth at clinically useful doses.
Kartica 657
Pitanje
Which term describes the T cell that coordinates other immune cells?
Odgovor
a helper T cell
Kartica 658
Pitanje
Which term describes a long-lived lymphocyte enabling faster re-exposure response?
Odgovor
an immune memory cell
Kartica 659
Pitanje
Which term describes safe antigen exposure used to create immune memory?
Odgovor
vaccination
Kartica 660
Pitanje
Which term describes a drug acting against bacteria?
Odgovor
an antibiotic
Kartica 661
Pitanje
What are examples of first-line defenses against pathogens?
Odgovor
Intact skin, mucus, cilia, antimicrobial secretions, stomach acidity, and competing microbiota.
Kartica 662
Pitanje
How does inflammation help defend damaged tissue?
Odgovor
It increases local blood flow and vessel permeability and recruits immune cells and defensive molecules.
Kartica 663
Pitanje
What happens during phagocytosis?
Odgovor
A cell surrounds a particle in a vesicle, then fuses it with digestive compartments to destroy or process it.
Kartica 664
Pitanje
How can antibodies help eliminate a pathogen?
Odgovor
They can neutralize targets, block attachment, clump particles, and mark them for phagocytosis or complement attack.
Kartica 665
Pitanje
Why can a vaccine generate protection without causing the full disease?
Odgovor
It presents antigen in a weakened, inactivated, partial, or encoded form that stimulates immunity with much lower risk.
Kartica 666
Pitanje
Why do antibiotics not treat viral infections?
Odgovor
Viruses lack the bacterial structures and independent metabolic processes targeted by antibiotics.
Kartica 667
Pitanje
What determines the antigen specificity of a lymphocyte?
Odgovor
The molecular shape and chemistry of its unique surface receptor.
Kartica 668
Pitanje
What is clonal selection?
Odgovor
An antigen activates lymphocytes with matching receptors, causing them to proliferate and differentiate.
Kartica 669
Pitanje
Why is a secondary adaptive immune response usually faster and stronger?
Odgovor
Memory cells are more numerous and activate rapidly, producing effective cells and antibodies sooner.
Kartica 670
Pitanje
How can high vaccination coverage protect some unvaccinated people?
Odgovor
Reduced transmission makes encounters with infectious individuals less likely, though protection is incomplete and pathogen-dependent.
Kartica 671
Pitanje
How does antibiotic use select for resistant bacteria?
Odgovor
Susceptible bacteria are removed while resistant variants survive and reproduce, increasing resistance-allele frequency.
Kartica 672
Pitanje
Why can unnecessary or incomplete antibiotic exposure promote resistance?
Odgovor
It creates selection favoring resistant cells while potentially leaving surviving bacteria to multiply and spread.
Kartica 673
Pitanje
What is an allergy?
Odgovor
An immune response to a normally harmless antigen that causes tissue symptoms or damage.
Kartica 674
Pitanje
What is asexual reproduction?
Odgovor
Production of offspring from one parent without fusion of gametes.
Kartica 675
Pitanje
What is sexual reproduction?
Odgovor
Production of offspring involving fusion of haploid gametes.
Kartica 676
Pitanje
What is a gamete?
Odgovor
A haploid reproductive cell able to fuse with another gamete.
Kartica 677
Pitanje
What is fertilization?
Odgovor
Fusion of gamete nuclei to form a diploid zygote.
Kartica 678
Pitanje
Which term describes reproduction without gamete fusion?
Odgovor
asexual reproduction
Kartica 679
Pitanje
Which term describes reproduction involving gamete fusion?
Odgovor
sexual reproduction
Kartica 680
Pitanje
Which term describes a haploid reproductive cell?
Odgovor
a gamete
Kartica 681
Pitanje
Which term describes fusion of gamete nuclei?
Odgovor
fertilization
Kartica 682
Pitanje
What is a zygote?
Odgovor
The diploid cell formed by fertilization.
Kartica 683
Pitanje
What is meiosis?
Odgovor
Cell division that halves chromosome number and usually produces genetically varied haploid cells.
Kartica 684
Pitanje
What is ovulation?
Odgovor
Release of a secondary oocyte from an ovary.
Kartica 685
Pitanje
What is implantation?
Odgovor
Attachment and embedding of an early embryo in the uterine lining.
Kartica 686
Pitanje
Which term describes the first diploid cell after fertilization?
Odgovor
a zygote
Kartica 687
Pitanje
Which term describes division producing varied haploid cells?
Odgovor
meiosis
Kartica 688
Pitanje
Which term describes release of an oocyte from an ovary?
Odgovor
ovulation
Kartica 689
Pitanje
Which term describes embedding of an early embryo in the uterine lining?
Odgovor
implantation
Kartica 690
Pitanje
What is the placenta?
Odgovor
A temporary organ that exchanges materials between maternal and fetal blood supplies without normally mixing them directly.
Kartica 691
Pitanje
What is pollination?
Odgovor
Transfer of pollen from an anther to a receptive stigma.
Kartica 692
Pitanje
Why does sexual reproduction usually produce more genetic variation than asexual reproduction?
Odgovor
Meiosis reshuffles alleles and random fertilization combines genomes from two gametes.
Kartica 693
Pitanje
Why must gametes be haploid?
Odgovor
Fusion of two haploid gametes restores the diploid chromosome number instead of doubling it each generation.
Kartica 694
Pitanje
Which term describes the maternal-fetal exchange organ?
Odgovor
the placenta
Kartica 695
Pitanje
Which term describes transfer of pollen to a stigma?
Odgovor
pollination
Kartica 696
Pitanje
What are major roles of FSH in the ovarian cycle?
Odgovor
It stimulates follicle development and supports estrogen secretion.
Kartica 697
Pitanje
What is a major role of the mid-cycle LH surge?
Odgovor
It triggers ovulation and formation of the corpus luteum.
Kartica 698
Pitanje
How does estrogen contribute to the uterine cycle?
Odgovor
It promotes repair and thickening of the uterine lining after menstruation.
Kartica 699
Pitanje
How does progesterone contribute to the uterine cycle?
Odgovor
It maintains a thick, secretory uterine lining after ovulation.
Kartica 700
Pitanje
Where does human fertilization usually occur?
Odgovor
In an oviduct, before the early embryo reaches the uterus.
Kartica 701
Pitanje
What happens after compatible pollen reaches a flower's stigma?
Odgovor
A pollen tube grows toward an ovule and delivers male nuclei for fertilization.
Kartica 702
Pitanje
Why does menstruation usually begin if pregnancy does not occur?
Odgovor
The corpus luteum degenerates, progesterone and estrogen fall, and the uterine lining is no longer maintained.
Kartica 703
Pitanje
What substances commonly cross the placenta between mother and fetus?
Odgovor
Oxygen and nutrients move toward the fetus; carbon dioxide and nitrogenous wastes move toward the mother.
Kartica 704
Pitanje
How can contraception prevent pregnancy in different ways?
Odgovor
Methods can inhibit ovulation, block sperm from reaching an egg, prevent fertilization, or permanently interrupt the reproductive ducts.
Kartica 705
Pitanje
What is homeostasis?
Odgovor
Maintenance of internal conditions within ranges compatible with normal function despite change.
Kartica 706
Pitanje
What is negative feedback?
Odgovor
Control in which a deviation triggers responses that oppose the original change.
Kartica 707
Pitanje
What is a set point?
Odgovor
The target value or range around which a regulated variable is maintained.
Kartica 708
Pitanje
What is a homeostatic receptor?
Odgovor
A sensor that detects a change in a regulated variable.
Kartica 709
Pitanje
Which term describes maintenance of a stable functional internal environment?
Odgovor
homeostasis
Kartica 710
Pitanje
Which term describes feedback that counteracts a deviation?
Odgovor
negative feedback
Kartica 711
Pitanje
Which term describes the target around which a variable is regulated?
Odgovor
a set point
Kartica 712
Pitanje
Which term describes the sensor in a feedback system?
Odgovor
a homeostatic receptor
Kartica 713
Pitanje
What is a control center?
Odgovor
The component that compares information with a target and coordinates a response.
Kartica 714
Pitanje
What is an effector?
Odgovor
A muscle, gland, or other component that carries out a control response.
Kartica 715
Pitanje
What is thermoregulation?
Odgovor
Control of body temperature within a functional range.
Kartica 716
Pitanje
What is vasodilation?
Odgovor
Widening of blood vessels, often increasing blood flow near the skin.
Kartica 717
Pitanje
Which term describes the feedback component that evaluates input and directs a response?
Odgovor
a control center
Kartica 718
Pitanje
Which term describes the component that executes a physiological response?
Odgovor
an effector
Kartica 719
Pitanje
Which term describes physiological regulation of body temperature?
Odgovor
thermoregulation
Kartica 720
Pitanje
Which term describes widening of blood vessels?
Odgovor
vasodilation
Kartica 721
Pitanje
What is vasoconstriction?
Odgovor
Narrowing of blood vessels, often reducing blood flow near the skin.
Kartica 722
Pitanje
What is insulin?
Odgovor
A pancreatic hormone that lowers elevated blood glucose by promoting uptake and storage.
Kartica 723
Pitanje
What is glucagon?
Odgovor
A pancreatic hormone that raises low blood glucose by promoting release of stored fuel.
Kartica 724
Pitanje
What are the main components of a homeostatic feedback loop?
Odgovor
A regulated variable, receptor, control center, effectors, and responses that alter the variable.
Kartica 725
Pitanje
Which term describes narrowing of blood vessels?
Odgovor
vasoconstriction
Kartica 726
Pitanje
Which term describes the pancreatic hormone that lowers blood glucose?
Odgovor
insulin
Kartica 727
Pitanje
Which term describes the pancreatic hormone that raises blood glucose?
Odgovor
glucagon
Kartica 728
Pitanje
What happens when blood glucose rises after a meal?
Odgovor
Insulin secretion increases, promoting glucose uptake and storage so blood glucose falls toward its normal range.
Kartica 729
Pitanje
What happens when blood glucose falls during fasting?
Odgovor
Glucagon secretion increases, promoting glycogen breakdown and glucose release by the liver.
Kartica 730
Pitanje
How does sweating cool the body?
Odgovor
Evaporation of water from skin transfers heat to the environment.
Kartica 731
Pitanje
How does skin vasodilation increase heat loss?
Odgovor
It brings more warm blood near the surface, increasing transfer of heat to the environment.
Kartica 732
Pitanje
How does shivering warm the body?
Odgovor
Rapid involuntary muscle contractions increase respiration and heat production.
Kartica 733
Pitanje
Does homeostasis keep internal conditions perfectly constant?
Odgovor
No. Variables fluctuate within controlled ranges around target values.
Kartica 734
Pitanje
How does ADH help conserve water?
Odgovor
It increases water permeability in kidney collecting ducts, so more water is reabsorbed and urine becomes more concentrated.
Kartica 735
Pitanje
How should ADH secretion change during dehydration?
Odgovor
It should increase, promoting greater water reabsorption by the kidneys.
Kartica 736
Pitanje
How does positive feedback differ from negative feedback?
Odgovor
Positive feedback amplifies a change until an endpoint; negative feedback opposes a change and stabilizes a variable.
Kartica 737
Pitanje
Why can diabetes mellitus cause persistently high blood glucose?
Odgovor
Insulin production may be insufficient or target cells may respond poorly to insulin.
Kartica 738
Pitanje
What is biological evolution?
Odgovor
Change in heritable characteristics or allele frequencies of a population across generations.
Kartica 739
Pitanje
What is allele frequency?
Odgovor
The proportion of gene copies in a population represented by a particular allele.
Kartica 740
Pitanje
What is microevolution?
Odgovor
Evolutionary change in allele frequencies within populations over relatively short timescales.
Kartica 741
Pitanje
What is speciation?
Odgovor
Evolutionary formation of new species.
Kartica 742
Pitanje
Which term describes change in a population's heritable composition across generations?
Odgovor
biological evolution
Kartica 743
Pitanje
Which term describes the proportion of a population's gene copies that are one allele?
Odgovor
allele frequency
Kartica 744
Pitanje
Which term describes short-timescale allele-frequency change within populations?
Odgovor
microevolution
Kartica 745
Pitanje
Which term describes formation of new species?
Odgovor
speciation
Kartica 746
Pitanje
What is reproductive isolation?
Odgovor
Barriers that prevent or greatly reduce gene flow between populations.
Kartica 747
Pitanje
What is allopatric speciation?
Odgovor
Speciation after populations become geographically separated and diverge.
Kartica 748
Pitanje
What is sympatric speciation?
Odgovor
Speciation without geographic separation, through reproductive isolation within the same area.
Kartica 749
Pitanje
What are homologous structures?
Odgovor
Structures similar because they were inherited from a common ancestor, even if their functions differ.
Kartica 750
Pitanje
Which term describes barriers reducing gene flow between populations?
Odgovor
reproductive isolation
Kartica 751
Pitanje
Which term describes speciation following geographic separation?
Odgovor
allopatric speciation
Kartica 752
Pitanje
Which term describes speciation within the same geographic area?
Odgovor
sympatric speciation
Kartica 753
Pitanje
Which term describes structures similar through common ancestry?
Odgovor
homologous structures
Kartica 754
Pitanje
What are analogous structures?
Odgovor
Structures with similar functions that evolved independently rather than from the same ancestral structure.
Kartica 755
Pitanje
What is a common ancestor?
Odgovor
An ancestral population from which two or more descendant lineages evolved.
Kartica 756
Pitanje
How does the fossil record provide evidence for evolution?
Odgovor
It documents organisms from different times, including appearance, change, persistence, and extinction of lineages.
Kartica 757
Pitanje
How do DNA and protein sequences provide evidence of common ancestry?
Odgovor
Shared sequences are inherited; greater similarity generally indicates more recent common ancestry.
Kartica 758
Pitanje
Which term describes functionally similar structures of independent evolutionary origin?
Odgovor
analogous structures
Kartica 759
Pitanje
Which term describes an ancestral population shared by descendant lineages?
Odgovor
a common ancestor
Kartica 760
Pitanje
What is the evolutionary significance of extinction?
Odgovor
It permanently ends a lineage and can alter ecological opportunities and the future diversification of survivors.
Kartica 761
Pitanje
Do individual organisms evolve during their lifetimes?
Odgovor
No. Individuals develop and acclimate; evolution is heritable change in populations across generations.
Kartica 762
Pitanje
Why is evolution represented as a branching tree rather than a ladder?
Odgovor
Lineages split from common ancestors; living species are not arranged as stages toward a single goal.
Kartica 763
Pitanje
How can island species support evolutionary explanations?
Odgovor
Their similarities to nearby mainland ancestors and unique local adaptations fit divergence after colonization and isolation.
Kartica 764
Pitanje
How can geographic isolation lead to reproductive isolation?
Odgovor
Separated populations accumulate different mutations and experience different selection and drift until interbreeding is reduced.
Kartica 765
Pitanje
Why can continuing gene flow slow speciation?
Odgovor
Movement of alleles between populations counteracts genetic divergence.
Kartica 766
Pitanje
Why can unrelated species evolve similar traits?
Odgovor
Similar environmental challenges can favor similar functional solutions through convergent evolution.
Kartica 767
Pitanje
Which parts of evolution are random and which are nonrandom?
Odgovor
Mutation and many sampling effects are random with respect to need; natural selection nonrandomly favors variants that reproduce better in a given environment.
Kartica 768
Pitanje
What is conservation biology?
Odgovor
The science and practice of protecting biodiversity, ecological processes, and evolutionary potential.
Kartica 769
Pitanje
What is habitat fragmentation?
Odgovor
Division of continuous habitat into smaller, isolated patches.
Kartica 770
Pitanje
What is an endangered species?
Odgovor
A species facing a high risk of extinction in the wild.
Kartica 771
Pitanje
What is in situ conservation?
Odgovor
Protection of species in their natural habitats and ecological communities.
Kartica 772
Pitanje
Which term describes the protection of biodiversity and ecological processes?
Odgovor
conservation biology
Kartica 773
Pitanje
Which term describes division of habitat into isolated patches?
Odgovor
habitat fragmentation
Kartica 774
Pitanje
Which term describes a species at high risk of extinction?
Odgovor
an endangered species
Kartica 775
Pitanje
Which term describes conservation within natural habitat?
Odgovor
in situ conservation
Kartica 776
Pitanje
What is ex situ conservation?
Odgovor
Protection of organisms or genetic material outside the natural habitat.
Kartica 777
Pitanje
What is a population bottleneck?
Odgovor
A sharp population reduction that can remove genetic variation by chance.
Kartica 778
Pitanje
What is a wildlife corridor?
Odgovor
Habitat connecting isolated patches to permit movement and gene flow.
Kartica 779
Pitanje
What major human-driven processes threaten biodiversity?
Odgovor
Habitat loss, overexploitation, invasive species, pollution, and climate change.
Kartica 780
Pitanje
Which term describes conservation outside natural habitat?
Odgovor
ex situ conservation
Kartica 781
Pitanje
Which term describes a severe population reduction that loses genetic diversity?
Odgovor
a population bottleneck
Kartica 782
Pitanje
Which term describes habitat linking isolated populations?
Odgovor
a wildlife corridor
Kartica 783
Pitanje
What makes a protected area more effective than a boundary alone?
Odgovor
Adequate size, representative habitat, enforcement, connectivity, local support, and management of external threats.
Kartica 784
Pitanje
Why is long-term population monitoring important in conservation?
Odgovor
It reveals trends, tests whether management works, and provides early warning of decline.
Kartica 785
Pitanje
How can ecosystem services support the case for conservation?
Odgovor
Healthy ecosystems provide benefits such as pollination, water purification, carbon storage, soil formation, and cultural value.
Kartica 786
Pitanje
Why are very small populations especially vulnerable to extinction?
Odgovor
Chance events, inbreeding, low genetic diversity, and difficulty finding mates can reinforce decline.
Kartica 787
Pitanje
What are benefits and limits of captive-breeding programs?
Odgovor
They can prevent immediate extinction and manage breeding, but may lose diversity, alter behavior, and fail without safe habitat for release.
Kartica 788
Pitanje
Why can controlling an invasive species aid conservation?
Odgovor
It can reduce predation, competition, disease, or habitat alteration affecting native species.
Kartica 789
Pitanje
Why must conservation priorities consider more than species count?
Odgovor
Endemism, evolutionary distinctness, ecological roles, threat severity, feasibility, and human needs also matter.
Kartica 790
Pitanje
What is an adaptation?
Odgovor
A heritable characteristic that increases reproductive success in a particular environment.
Kartica 791
Pitanje
What is acclimation?
Odgovor
A reversible physiological or behavioral adjustment by an individual to environmental change.
Kartica 792
Pitanje
What is a structural adaptation?
Odgovor
An inherited anatomical feature that improves performance in an environment.
Kartica 793
Pitanje
What is a physiological adaptation?
Odgovor
An inherited functional or biochemical feature that improves performance in an environment.
Kartica 794
Pitanje
Which term describes a heritable trait improving reproductive success in context?
Odgovor
an adaptation
Kartica 795
Pitanje
Which term describes an individual's reversible adjustment to environmental change?
Odgovor
acclimation
Kartica 796
Pitanje
Which term describes an adaptive anatomical feature?
Odgovor
a structural adaptation
Kartica 797
Pitanje
Which term describes an adaptive functional or biochemical feature?
Odgovor
a physiological adaptation
Kartica 798
Pitanje
What is a behavioral adaptation?
Odgovor
An inherited behavior pattern that improves survival or reproduction.
Kartica 799
Pitanje
What is an environmental tolerance range?
Odgovor
The range of an abiotic condition within which an organism can survive and reproduce.
Kartica 800
Pitanje
What is evolutionary fitness?
Odgovor
Relative contribution of an individual or genotype to future generations.
Kartica 801
Pitanje
How can a thick cuticle and reduced leaves help a desert plant?
Odgovor
The cuticle lowers surface permeability, while smaller leaves reduce the area from which water can evaporate.
Kartica 802
Pitanje
Which term describes an adaptive behavior pattern?
Odgovor
a behavioral adaptation
Kartica 803
Pitanje
Which term describes the survivable range of an abiotic condition?
Odgovor
an environmental tolerance range
Kartica 804
Pitanje
Which term describes relative reproductive contribution to future generations?
Odgovor
evolutionary fitness
Kartica 805
Pitanje
How can a streamlined body adapt an aquatic animal to movement?
Odgovor
It reduces drag, lowering the energy needed to move through water.
Kartica 806
Pitanje
Does an organism develop an adaptation because it needs one?
Odgovor
No. Heritable variants arise without regard to need, and selection changes their frequencies across generations.
Kartica 807
Pitanje
Why may organisms from different thermal environments have enzymes with different temperature optima?
Odgovor
Selection favors protein structures that balance flexibility and stability under local temperatures.
Kartica 808
Pitanje
Why is an adaptation rarely beneficial in every environment?
Odgovor
Traits carry costs and their advantage depends on local resources, competitors, predators, and physical conditions.
Kartica 809
Pitanje
How does phenotypic plasticity differ from genetic adaptation?
Odgovor
Plasticity lets one genotype produce different phenotypes; adaptation is a heritable population trait shaped across generations.
Kartica 810
Pitanje
What is local adaptation?
Odgovor
A population has higher fitness in its home environment than foreign populations because selection favored local traits.
Kartica 811
Pitanje
What is an ecological niche?
Odgovor
The set of environmental conditions, resources, interactions, and functional roles associated with a species.
Kartica 812
Pitanje
What is a habitat?
Odgovor
The physical place or environment where an organism lives.
Kartica 813
Pitanje
What is a fundamental niche?
Odgovor
The full range of conditions and resources a species could use without limiting biotic interactions.
Kartica 814
Pitanje
What is a realized niche?
Odgovor
The conditions and resources a species actually uses after competition and other interactions.
Kartica 815
Pitanje
Which term describes a species' environmental requirements and ecological role?
Odgovor
an ecological niche
Kartica 816
Pitanje
Which term describes the place where an organism lives?
Odgovor
a habitat
Kartica 817
Pitanje
Which term describes the potential niche without limiting biotic interactions?
Odgovor
a fundamental niche
Kartica 818
Pitanje
Which term describes the niche actually occupied in nature?
Odgovor
a realized niche
Kartica 819
Pitanje
What is competition?
Odgovor
An interaction in which organisms reduce one another's access to a limited resource.
Kartica 820
Pitanje
What is mutualism?
Odgovor
An interaction in which both participating species benefit.
Kartica 821
Pitanje
What is predation?
Odgovor
An interaction in which one organism kills and consumes another.
Kartica 822
Pitanje
How does a habitat differ from a niche?
Odgovor
A habitat is where an organism lives; a niche includes how it uses conditions and resources and interacts there.
Kartica 823
Pitanje
Which term describes an interaction over a limited resource that harms both competitors?
Odgovor
competition
Kartica 824
Pitanje
Which term describes an interspecific interaction benefiting both partners?
Odgovor
mutualism
Kartica 825
Pitanje
Which term describes an interaction where one organism kills and eats another?
Odgovor
predation
Kartica 826
Pitanje
What kinds of factors define a niche?
Odgovor
Abiotic factors such as temperature and moisture, plus biotic factors such as food, competitors, predators, and partners.
Kartica 827
Pitanje
What does competitive exclusion predict?
Odgovor
Species with effectively identical niches cannot coexist indefinitely under stable conditions; one is excluded or niches diverge.
Kartica 828
Pitanje
How can resource partitioning reduce competition?
Odgovor
Species use different resources, places, or times, reducing niche overlap.
Kartica 829
Pitanje
What is a keystone species?
Odgovor
A species whose effect on community structure is disproportionately large relative to its abundance.
Kartica 830
Pitanje
Why can an introduced species expand rapidly in a new community?
Odgovor
It may encounter abundant resources, suitable climate, and fewer predators, pathogens, or competitors.
Kartica 831
Pitanje
Can an organism alter the niche conditions of other species?
Odgovor
Yes. Ecosystem engineers modify habitat structure or resource availability, changing opportunities for other organisms.
Kartica 832
Pitanje
What is a population?
Odgovor
Individuals of the same species living in the same area at the same time.
Kartica 833
Pitanje
What is an ecological community?
Odgovor
Populations of different species living and interacting in an area.
Kartica 834
Pitanje
What is an ecosystem?
Odgovor
A community together with its physical environment and their interactions.
Kartica 835
Pitanje
What is carrying capacity?
Odgovor
The population size an environment can sustain over time under given conditions.
Kartica 836
Pitanje
Which term describes same-species individuals sharing an area and time?
Odgovor
a population
Kartica 837
Pitanje
Which term describes interacting populations of different species?
Odgovor
an ecological community
Kartica 838
Pitanje
Which term describes a community plus its abiotic environment?
Odgovor
an ecosystem
Kartica 839
Pitanje
Which term describes the long-term supportable population size?
Odgovor
carrying capacity
Kartica 840
Pitanje
What is population density?
Odgovor
The number of individuals per unit area or volume.
Kartica 841
Pitanje
What is a limiting factor?
Odgovor
A resource or condition that restricts population growth or distribution.
Kartica 842
Pitanje
What is a density-dependent factor?
Odgovor
A factor whose effect strengthens as population density increases.
Kartica 843
Pitanje
What is a density-independent factor?
Odgovor
A factor whose effect is not primarily determined by population density.
Kartica 844
Pitanje
Which term describes individuals per unit area or volume?
Odgovor
population density
Kartica 845
Pitanje
Which term describes a resource or condition restricting a population?
Odgovor
a limiting factor
Kartica 846
Pitanje
Which term describes a factor with stronger effects at higher density?
Odgovor
a density-dependent factor
Kartica 847
Pitanje
Which term describes a factor acting largely regardless of population density?
Odgovor
a density-independent factor
Kartica 848
Pitanje
What is exponential population growth?
Odgovor
Growth at a constant per-capita rate, producing a J-shaped curve under ideal conditions.
Kartica 849
Pitanje
What is logistic population growth?
Odgovor
Growth that slows as population size approaches carrying capacity, producing an S-shaped model.
Kartica 850
Pitanje
What four processes directly change population size?
Odgovor
Births and immigration increase it; deaths and emigration decrease it.
Kartica 851
Pitanje
Under what conditions can exponential growth occur temporarily?
Odgovor
Resources are abundant and limiting effects such as competition, disease, and predation are weak.
Kartica 852
Pitanje
Which term describes J-shaped growth at constant per-capita rate?
Odgovor
exponential population growth
Kartica 853
Pitanje
Which term describes S-shaped growth that slows near carrying capacity?
Odgovor
logistic population growth
Kartica 854
Pitanje
Why is infectious disease often density dependent?
Odgovor
Close or frequent contact at high density increases transmission opportunities.
Kartica 855
Pitanje
Give an example of a density-independent population factor.
Odgovor
A severe storm, wildfire, drought, or freeze can affect populations regardless of their initial density.
Kartica 856
Pitanje
When is quadrat sampling useful?
Odgovor
For estimating abundance or frequency of sessile or slow-moving organisms in defined areas.
Kartica 857
Pitanje
What can a transect reveal?
Odgovor
How species occurrence or abundance changes along an environmental gradient.
Kartica 858
Pitanje
What can happen when a population overshoots carrying capacity?
Odgovor
Resource depletion may raise mortality or lower reproduction, causing decline or oscillation.
Kartica 859
Pitanje
What is the basic mark–recapture estimate of population size?
Odgovor
First sample marked × second sample total ÷ marked individuals recaptured.
Kartica 860
Pitanje
What assumptions improve a mark–recapture estimate?
Odgovor
Marks persist and do not affect survival, marked individuals mix, capture probability is similar, and the population is effectively closed.
Kartica 861
Pitanje
Why does a correlation between two population variables not prove causation?
Odgovor
A third factor, reverse influence, chance, or biased sampling could produce the association.
Kartica 862
Pitanje
What is a trophic level?
Odgovor
A feeding position in a food chain or web.
Kartica 863
Pitanje
What is a producer?
Odgovor
An autotroph that converts inorganic carbon into organic matter.
Kartica 864
Pitanje
What is a consumer?
Odgovor
An organism obtaining energy and matter by eating other organisms or organic material.
Kartica 865
Pitanje
What is a decomposer?
Odgovor
An organism that externally digests dead material and wastes and absorbs the products.
Kartica 866
Pitanje
Which term describes a feeding position in an ecosystem?
Odgovor
a trophic level
Kartica 867
Pitanje
Which term describes an autotroph forming organic matter?
Odgovor
a producer
Kartica 868
Pitanje
Which term describes an organism feeding on other organic matter?
Odgovor
a consumer
Kartica 869
Pitanje
Which term describes an organism digesting dead organic matter externally?
Odgovor
a decomposer
Kartica 870
Pitanje
What is a food chain?
Odgovor
A linear representation of feeding and energy-transfer relationships.
Kartica 871
Pitanje
What is a food web?
Odgovor
A network of interconnected feeding relationships in a community.
Kartica 872
Pitanje
What is gross primary productivity?
Odgovor
The total rate at which producers capture energy into organic matter.
Kartica 873
Pitanje
What is net primary productivity?
Odgovor
Producer energy stored as new biomass after subtracting producer respiration from gross primary productivity.
Kartica 874
Pitanje
Which term describes a linear feeding sequence?
Odgovor
a food chain
Kartica 875
Pitanje
Which term describes a network of connected food chains?
Odgovor
a food web
Kartica 876
Pitanje
Which term describes the total producer energy-capture rate?
Odgovor
gross primary productivity
Kartica 877
Pitanje
Which term describes producer biomass gain after respiration?
Odgovor
net primary productivity
Kartica 878
Pitanje
What is ecological productivity?
Odgovor
The rate of biomass or energy production per unit area or volume.
Kartica 879
Pitanje
What is a biogeochemical cycle?
Odgovor
Movement of an element or compound through organisms and the physical environment.
Kartica 880
Pitanje
Why is less energy available at each higher trophic level?
Odgovor
Not all biomass is eaten or digested, and organisms use energy in respiration, movement, maintenance, and heat loss.
Kartica 881
Pitanje
Why does energy flow rather than cycle through an ecosystem?
Odgovor
Energy enters mainly as light and ultimately disperses as heat, which ecosystems cannot fully recycle.
Kartica 882
Pitanje
Which term describes the rate of biomass or energy production?
Odgovor
ecological productivity
Kartica 883
Pitanje
Which term describes cycling of matter through living and nonliving reservoirs?
Odgovor
a biogeochemical cycle
Kartica 884
Pitanje
Why can matter cycle through an ecosystem?
Odgovor
Atoms are conserved and repeatedly transferred among organisms, detritus, soil, water, and atmosphere.
Kartica 885
Pitanje
Why is a pyramid of energy always upright?
Odgovor
Usable energy decreases between trophic levels because every transfer includes losses.
Kartica 886
Pitanje
How are gross and net primary productivity related?
Odgovor
NPP = GPP − producer respiration.
Kartica 887
Pitanje
How do decomposers support nutrient cycling?
Odgovor
They break down dead material and wastes, releasing inorganic nutrients for reuse.
Kartica 888
Pitanje
What processes move carbon rapidly between organisms and the atmosphere?
Odgovor
Photosynthesis removes carbon dioxide; respiration, decomposition, and combustion release it.
Kartica 889
Pitanje
Why is nitrogen fixation important?
Odgovor
It converts atmospheric nitrogen gas into forms that can enter biological nitrogen metabolism.
Kartica 890
Pitanje
How can excess nitrogen or phosphorus cause eutrophication?
Odgovor
Nutrient enrichment drives algal growth; decomposition of the biomass consumes oxygen and can create hypoxic water.
Kartica 891
Pitanje
Why can a persistent pollutant reach higher concentrations at higher trophic levels?
Odgovor
Predators consume contaminant stored in many prey, and the substance is not readily broken down or excreted.
Kartica 892
Pitanje
How is trophic-transfer efficiency calculated?
Odgovor
Energy or biomass gained by the higher trophic level ÷ energy or biomass available at the lower level × 100%.
Kartica 893
Pitanje
What is phenotypic variation?
Odgovor
Differences in observable traits among individuals of a population.
Kartica 894
Pitanje
What is heritable variation?
Odgovor
Trait differences that can be transmitted genetically to offspring.
Kartica 895
Pitanje
What is a selection pressure?
Odgovor
An environmental factor causing differences in survival or reproduction among phenotypes.
Kartica 896
Pitanje
What is relative fitness?
Odgovor
An individual's reproductive success compared with others in the population.
Kartica 897
Pitanje
Which term describes observable differences among individuals?
Odgovor
phenotypic variation
Kartica 898
Pitanje
Which term describes genetically transmissible trait differences?
Odgovor
heritable variation
Kartica 899
Pitanje
Which term describes an environmental factor producing differential reproductive success?
Odgovor
a selection pressure
Kartica 900
Pitanje
Which term describes reproductive success relative to other individuals?
Odgovor
relative fitness
Kartica 901
Pitanje
What is directional selection?
Odgovor
Selection favoring one extreme phenotype and shifting a population's trait distribution.
Kartica 902
Pitanje
What is stabilizing selection?
Odgovor
Selection favoring intermediate phenotypes and acting against extremes.
Kartica 903
Pitanje
What is disruptive selection?
Odgovor
Selection favoring both extreme phenotypes over intermediates.
Kartica 904
Pitanje
What is sexual selection?
Odgovor
Selection arising from differences in mating success.
Kartica 905
Pitanje
Which term describes selection shifting a trait toward one extreme?
Odgovor
directional selection
Kartica 906
Pitanje
Which term describes selection favoring intermediate phenotypes?
Odgovor
stabilizing selection
Kartica 907
Pitanje
Which term describes selection favoring both trait extremes?
Odgovor
disruptive selection
Kartica 908
Pitanje
Which term describes selection caused by unequal mating success?
Odgovor
sexual selection
Kartica 909
Pitanje
What conditions are required for natural selection?
Odgovor
Individuals vary, some variation is heritable, more offspring are produced than can reproduce, and variants differ in reproductive success.
Kartica 910
Pitanje
How does natural selection produce antibiotic-resistant bacterial populations?
Odgovor
Existing resistant variants survive treatment and reproduce more than susceptible bacteria.
Kartica 911
Pitanje
Does an antibiotic cause bacteria to mutate specifically toward resistance?
Odgovor
No. Resistance variants arise without regard to need; treatment selects among them.
Kartica 912
Pitanje
Can an individual become genetically adapted through natural selection?
Odgovor
No. Selection acts on individuals, but adaptation is a population change across generations.
Kartica 913
Pitanje
How does artificial selection differ from natural selection?
Odgovor
Humans choose breeding traits in artificial selection; environmental conditions determine differential reproduction in natural selection.
Kartica 914
Pitanje
How does natural selection change a population?
Odgovor
Individuals with advantageous heritable variants leave more offspring, increasing those alleles over generations.
Kartica 915
Pitanje
Why is fitness environment-dependent?
Odgovor
A trait that improves reproduction in one environment may be neutral or costly in another.
Kartica 916
Pitanje
How does genetic drift differ from natural selection?
Odgovor
Drift changes allele frequencies by chance sampling; selection changes them through consistent fitness differences.
Kartica 917
Pitanje
What is ecosystem stability?
Odgovor
The capacity of an ecosystem to maintain or recover its structure and functions despite disturbance.
Kartica 918
Pitanje
What is an ecological tipping point?
Odgovor
A threshold beyond which feedbacks can drive a large and difficult-to-reverse ecosystem shift.
Kartica 919
Pitanje
What is a mesocosm?
Odgovor
A controlled, simplified ecosystem used to investigate ecological processes under more realistic conditions than a small laboratory vessel.
Kartica 920
Pitanje
What is a sustainable yield?
Odgovor
A harvest rate that can continue without causing long-term resource decline under prevailing conditions.
Kartica 921
Pitanje
Which term describes the capacity of an ecosystem to persist or recover after disturbance?
Odgovor
ecosystem stability
Kartica 922
Pitanje
Which term describes a threshold triggering a major hard-to-reverse ecosystem shift?
Odgovor
an ecological tipping point
Kartica 923
Pitanje
Which term describes a controlled model ecosystem used for experiments?
Odgovor
a mesocosm
Kartica 924
Pitanje
Which term describes a harvest rate that avoids long-term depletion?
Odgovor
a sustainable yield
Kartica 925
Pitanje
What is eutrophication?
Odgovor
Nutrient enrichment of water that stimulates excess primary production and can lead to oxygen depletion.
Kartica 926
Pitanje
What is biomagnification?
Odgovor
Increase in concentration of a persistent pollutant at successively higher trophic levels.
Kartica 927
Pitanje
What is rewilding?
Odgovor
Ecosystem restoration that rebuilds natural processes, species interactions, and self-sustaining ecological function.
Kartica 928
Pitanje
What features can make an ecosystem more stable?
Odgovor
Diverse functional roles, connected habitats, intact food webs, nutrient cycling, and balancing feedbacks can help the system resist or recover from disturbance.
Kartica 929
Pitanje
Which term describes nutrient enrichment that can deplete oxygen in water?
Odgovor
eutrophication
Kartica 930
Pitanje
Which term describes increasing pollutant concentration up a food chain?
Odgovor
biomagnification
Kartica 931
Pitanje
Which term describes restoration focused on natural processes and self-sustaining ecosystems?
Odgovor
rewilding
Kartica 932
Pitanje
How could extensive Amazon deforestation push the ecosystem toward a tipping point?
Odgovor
Loss of trees can reduce rainfall recycling and increase heat and fire, which cause further forest loss and may shift large areas toward a drier state.
Kartica 933
Pitanje
What are a benefit and a limitation of using a mesocosm?
Odgovor
It allows controlled experiments with interacting organisms, but its simplified scale cannot reproduce every process or long-term influence in a natural ecosystem.
Kartica 934
Pitanje
Why should a fishery harvest below an uncertain maximum sustainable yield?
Odgovor
Population estimates and recruitment vary, so a safety margin reduces the chance that error or a poor breeding year drives long-term decline.
Kartica 935
Pitanje
How can intensive agriculture reduce ecosystem stability?
Odgovor
Habitat loss, low crop diversity, soil degradation, heavy water use, pesticides, and nutrient runoff can weaken food webs and ecosystem processes.
Kartica 936
Pitanje
Why can microplastic pollution harm aquatic ecosystems?
Odgovor
Small persistent particles can be ingested, carry additives or other pollutants, damage feeding and tissues, and move through food webs.
Kartica 937
Pitanje
How can rewilding improve ecosystem stability?
Odgovor
Restoring native species, habitat connections, and natural disturbance or grazing processes can rebuild feedbacks and allow the ecosystem to maintain itself with less intervention.
Kartica 938
Pitanje
What is the greenhouse effect?
Odgovor
Warming caused when atmospheric gases absorb and re-emit outgoing infrared radiation.
Kartica 939
Pitanje
What is a greenhouse gas?
Odgovor
An atmospheric gas that absorbs infrared radiation at wavelengths emitted by Earth.
Kartica 940
Pitanje
What is carbon dioxide (CO₂)?
Odgovor
A long-lived greenhouse gas increased mainly by fossil-fuel combustion, cement production, and land-use change.
Kartica 941
Pitanje
What is methane (CH₄)?
Odgovor
A potent greenhouse gas emitted by sources including fossil-fuel systems, livestock, rice cultivation, wetlands, and waste.
Kartica 942
Pitanje
Which term describes warming from absorption and re-emission of infrared radiation?
Odgovor
the greenhouse effect
Kartica 943
Pitanje
Which term describes an atmospheric infrared-absorbing gas?
Odgovor
a greenhouse gas
Kartica 944
Pitanje
Which term describes the long-lived greenhouse gas strongly increased by fossil fuels?
Odgovor
carbon dioxide (CO₂)
Kartica 945
Pitanje
Which term describes the potent short-lived greenhouse gas from biological and fossil sources?
Odgovor
methane (CH₄)
Kartica 946
Pitanje
What is albedo?
Odgovor
The fraction of incoming radiation reflected by a surface.
Kartica 947
Pitanje
What is a carbon sink?
Odgovor
A reservoir that absorbs more carbon than it releases over a specified period.
Kartica 948
Pitanje
What is ocean acidification?
Odgovor
Decline in seawater pH caused mainly by absorption of human-emitted carbon dioxide.
Kartica 949
Pitanje
What is climate change?
Odgovor
A persistent change in the statistical patterns of climate over decades or longer.
Kartica 950
Pitanje
Which term describes surface reflectivity?
Odgovor
albedo
Kartica 951
Pitanje
Which term describes a reservoir with net carbon uptake?
Odgovor
a carbon sink
Kartica 952
Pitanje
Which term describes seawater pH decline from absorbed carbon dioxide?
Odgovor
ocean acidification
Kartica 953
Pitanje
Which term describes long-term change in climate patterns?
Odgovor
climate change
Kartica 954
Pitanje
What is the enhanced greenhouse effect?
Odgovor
Additional warming caused by human-driven increases in greenhouse-gas concentrations.
Kartica 955
Pitanje
How do climate mitigation and climate adaptation differ?
Odgovor
Mitigation limits the magnitude of climate change; adaptation reduces harm from changes that occur.
Kartica 956
Pitanje
How does increasing greenhouse-gas concentration alter Earth's energy balance?
Odgovor
Less outgoing infrared energy initially escapes to space, so the climate warms until energy balance is restored at a higher temperature.
Kartica 957
Pitanje
How can melting ice amplify warming?
Odgovor
Less bright ice lowers albedo, so darker land or water absorbs more solar energy and causes further warming.
Kartica 958
Pitanje
How can climate change alter species distributions?
Odgovor
Temperature, rainfall, seasons, sea level, and interactions shift, moving or shrinking areas with suitable conditions.
Kartica 959
Pitanje
Why can ocean acidification harm calcifying organisms?
Odgovor
Carbonate chemistry changes, reducing availability of carbonate ions used to build calcium-carbonate structures.
Kartica 960
Pitanje
How can ecosystem protection contribute to climate mitigation?
Odgovor
Protecting forests, wetlands, soils, and coastal habitats can avoid emissions and maintain or increase carbon storage.
960 kartica
IB Biology SL Flashcards: Complete Course Review
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