OAE Biology flashcards
OAE Biology · 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 by the researcher in an experiment; its effect on the dependent variable is measured while other variables are held constant.
- Scientific theory
- A well-substantiated explanatory framework supported by extensive evidence and repeated testing, broader and better supported than a hypothesis.
- Correlation versus causation
- An association between two variables does not prove one causes the other; confounding variables or reverse causation may explain the relationship.
- Peer review
- Evaluation of a research manuscript by independent experts who assess methodological soundness and significance before publication; it filters but does not guarantee correctness.
- Control group
- The comparison group that receives no treatment or a placebo, providing a baseline to isolate the effect of the independent variable.
- Cell theory
- The principle that all living organisms consist of cells, the cell is the basic unit of life, and new cells arise from existing cells.
- Endosymbiotic theory
- The proposal that mitochondria and chloroplasts originated from engulfed bacteria, supported by their own circular DNA, 70S ribosomes, and double membranes.
- Fluid mosaic model
- The description of membranes as a phospholipid bilayer with embedded proteins and cholesterol that move laterally, giving the membrane dynamic structure.
- Competitive inhibition
- An inhibitor binds the enzyme active site, blocking substrate access; raising substrate concentration can overcome the inhibition and restore reaction rate.
- Glycolysis
- The cytosolic pathway splitting glucose into two pyruvate molecules, producing a net gain 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 molecule contains one original parental strand and one newly synthesized strand, following complementary base pairing during replication.
- Mendel's law of segregation
- The two alleles of a gene separate during meiosis so each gamete receives only one allele, restoring pairs at fertilization.
- Hardy-Weinberg equilibrium
- Allele and genotype frequencies remain constant across generations when there is no mutation, migration, selection, or drift and mating is random.
- Frameshift mutation
- An insertion or deletion of bases not in multiples of three, shifting the reading frame and typically altering all downstream amino acids.
- Genetic drift
- Random change in allele frequencies across generations, most pronounced in small populations; bottleneck and founder effects are examples.
- Natural selection
- Differential reproductive success of individuals with heritable traits better suited to the environment, shifting allele frequencies in a population over generations.
- Allopatric speciation
- Speciation that occurs when a geographic barrier separates populations, preventing gene flow and allowing independent evolutionary divergence.
- Three domains of life
- The classification of organisms into Bacteria, Archaea, and Eukarya; Archaea differ from Bacteria in membrane lipids and molecular machinery.
- Binomial nomenclature
- The two-part naming system giving each species a capitalized genus and lowercase species epithet, both italicized in print.
- Homologous structures
- Anatomical features shared by related organisms because of common ancestry, even when the structures differ in function, such as forelimbs of vertebrates.
- Analogous structures
- Features with similar function but different evolutionary origins, such as bird and insect wings, indicating convergent evolution rather than shared ancestry.
- Angiosperms
- Flowering vascular plants that produce seeds enclosed in fruit and undergo double fertilization, forming the most diverse plant group.
- Fungi nutrition
- Fungi are heterotrophs that absorb nutrients after secreting digestive enzymes; their cell walls contain chitin, and many form mycorrhizae with plants.
- Ten percent rule
- Only about ten percent of energy at one trophic level transfers to the next; the rest is lost mainly as heat, limiting food chain length.
- Carrying capacity
- The maximum population size an environment can sustain indefinitely given available resources; logistic growth levels off at this value.
- Keystone species
- A species whose influence on ecosystem structure is disproportionate to its abundance; its removal triggers cascading changes across the community.
- Primary succession
- Ecological succession beginning on bare substrate such as lava or rock, where no soil exists and pioneer species must first establish.
- Nitrogen fixation
- Conversion of atmospheric nitrogen gas into ammonia by bacteria such as Rhizobium and cyanobacteria, making nitrogen available to living organisms.
- Informed consent
- Voluntary agreement to participate in research after full disclosure of purpose, risks, benefits, and alternatives, given by a person with decision-making capacity.
- Herd immunity
- Indirect protection of unvaccinated individuals that occurs when a sufficiently high proportion of a population is immune to a contagious disease.
- Antibiotic resistance
- Bacteria survive antibiotic exposure through inherited or acquired mechanisms; overuse selects resistant strains and reduces treatment effectiveness.