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