AEPA Biology (NT305) flashcards
AEPA Biology (NT305) · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Independent variable
- The factor deliberately manipulated or varied by the researcher in an experiment; its effect on the measured dependent variable is what the study tests.
- Control group
- A comparison group that does not receive the experimental treatment, used to isolate the effect of the independent variable from other influences.
- Falsifiability
- The property of a scientific claim that makes it possible to be disproved by observation or experiment; unfalsifiable claims fall outside empirical science.
- Scientific theory
- A well-substantiated explanatory framework supported by many independent lines of evidence, broader than a hypothesis and not a tentative guess.
- Reliability versus validity
- Reliability is consistency of repeated measurements, while validity is the degree to which a measurement reflects the variable it is intended to measure.
- Standard error
- The standard deviation of a sampling distribution, estimated as s divided by the square root of n; it shrinks as sample size grows.
- Endosymbiotic theory
- The proposal that mitochondria and chloroplasts descended from engulfed prokaryotes, supported by their circular DNA, ribosomes, and double membranes.
- Enzyme function
- Enzymes are catalysts that lower activation energy by stabilizing transition states, without altering the reaction's free-energy change or equilibrium.
- Competitive inhibition
- An inhibitor binds the enzyme active site, competing with substrate; it raises the apparent Km but leaves maximum velocity unchanged.
- Osmosis
- Net movement of water across a selectively permeable membrane from a region of lower solute concentration to one of higher solute concentration.
- Glycolysis
- The cytoplasmic pathway that splits glucose into two pyruvate molecules, producing a net of two ATP and two NADH without requiring oxygen.
- Calvin cycle
- The light-independent reactions in the chloroplast stroma where rubisco fixes carbon dioxide into sugar using ATP and NADPH from the light reactions.
- Semiconservative replication
- Each new DNA double helix contains one original parental strand and one newly synthesized strand, as demonstrated by the Meselson-Stahl experiment.
- Transcription
- Synthesis of an RNA molecule from a DNA template strand, catalyzed by RNA polymerase, producing mRNA that carries the coding message.
- Dihybrid cross ratio
- The 9:3:3:1 phenotypic ratio expected in the F2 generation of a cross between parents differing in two unlinked genes.
- Hardy-Weinberg equilibrium
- Allele and genotype frequencies remain constant across generations when there is no mutation, migration, selection, or drift and mating is random.
- Genetic drift
- Random change in allele frequencies due to chance sampling, strongest in small populations; founder effect and bottleneck are examples.
- Allopatric speciation
- Speciation that occurs when a geographic barrier separates populations, preventing gene flow and allowing independent evolutionary divergence.
- Natural selection
- Differential survival and reproduction of individuals based on heritable phenotypic variation, leading to changes in allele frequencies over generations.
- Surface area to volume ratio
- The ratio of an organism's exchange surface to its mass; it decreases with increasing size, limiting diffusion and favoring specialized exchange organs.
- Xylem versus phloem
- Xylem conducts water and dissolved minerals upward from roots; phloem transports sugars and other solutes bidirectionally between sources and sinks.
- Negative feedback
- A regulatory mechanism in which a change triggers a response that counteracts the change, stabilizing a physiological variable near a set point.
- Bilateral symmetry
- Body plan with a single plane dividing the organism into mirror-image halves, typically associated with cephalization and directed locomotion.
- Fungal nutrition
- Fungi are heterotrophs that absorb nutrients after secreting digestive enzymes, and their cell walls contain chitin rather than cellulose.
- Amniotic egg
- An egg with protective membranes and a shell that retains water, an adaptation allowing reptiles, birds, and mammals to reproduce on land.
- Trophic efficiency
- The proportion of energy at one trophic level transferred to the next, typically about ten percent, limiting food chain length.
- Carrying capacity
- The maximum population size that an environment can sustain indefinitely given available resources; logistic growth approaches this value asymptotically.
- Primary succession
- Community development on newly exposed substrate lacking soil, such as bare rock or lava flows, beginning with pioneer species like lichens.
- Keystone species
- A species whose influence on community structure is disproportionate to its abundance; its removal can trigger cascading changes in the ecosystem.
- Nitrification
- The microbial oxidation of ammonium to nitrite and then nitrate in the nitrogen cycle, making nitrogen available to plants.
- Mutualism
- A species interaction in which both participants benefit, such as pollinators receiving nectar while plants achieve fertilization.
- Exponential growth
- Population growth at a constant per capita rate when resources are unlimited, described by dN/dt = rN and producing a J-shaped curve.