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