AP Biology Unit 1-8 Master Review

A comprehensive set of vocabulary flashcards covering the core concepts of AP Biology units 1 through 8, including chemical foundations, cell biology, genetics, evolution, and ecology.

CHNOPS

A memory phrase for the major elements that make up living organisms: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, and Sulfur.

Trace elements

Essential minerals required by organisms in very small amounts, such as Iron for hemoglobin, Iodine for thyroid hormones, and Copper as an enzyme cofactor.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons, such as Carbon-12 and Carbon-14.

Polar covalent bonds

A type of bond where electrons are shared unequally between atoms, such as in water where oxygen pulls electrons more strongly than hydrogen.

Hydrogen bonds

Weak attractions between a partially positive hydrogen atom and a partially negative atom, often oxygen or nitrogen; they are critical for water properties, DNA base pairing, and protein structure.

Cohesion

A property of water where water molecules stick to each other, often resulting in the formation of droplets.

Adhesion

A property of water where water molecules stick to other substances, such as plant cell walls.

Capillary Action

The upward movement of water through narrow tubes, such as plant xylem, caused by the combined forces of cohesion and adhesion.

Surface Tension

The result of water molecules sticking together at the surface, allowing small organisms like water striders to stand on the water's surface.

High Specific Heat

The property of water that allows it to resist temperature changes, helping organisms and environments maintain stable temperatures.

Expansion Upon Freezing

A unique property where ice is less dense than liquid water because hydrogen bonds hold molecules in a spaced-out structure, allowing ice to float and insulate the water below.

Universal Solvent

A description of water reflecting its ability to dissolve many polar and ionic substances, which is essential for biological reactions in aqueous environments.

pH Scale Formula

$$\text{pH} = -\log[H+]$$

Buffers

Substances that resist changes in pH, helping maintain the stable environment necessary for enzyme and cell function.

Dehydration Synthesis

A chemical reaction that builds polymers by removing a water molecule.

Hydrolysis

A chemical reaction that breaks down polymers into monomers by adding a water molecule.

Monosaccharides

Single sugar building blocks, such as Glucose, Fructose, and Galactose.

Glycosidic bond

The bond that joins two monosaccharides to form a disaccharide.

Starch

A polysaccharide used for energy storage in plants, made entirely of glucose monomers.

Glycogen

A polysaccharide used for energy storage in animals, primarily stored in the liver and muscles.

Cellulose

A structural polysaccharide found in plant cell walls that humans cannot digest due to its specific bond structure.

Chitin

A structural polysaccharide found in fungal cell walls and the exoskeletons of arthropods.

Amphipathic

A molecule that has both hydrophilic and hydrophobic regions, such as a phospholipid.

Steroids

Lipids characterized by a four-carbon ring structure, such as cholesterol, which regulates membrane fluidity.

Primary Structure

The specific sequence of amino acids in a polypeptide chain.

Secondary Structure

Local folding patterns in a protein, such as alpha helices and beta pleated sheets, held together by hydrogen bonds.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide, determined by interactions like hydrophobic forces, ionic bonds, and disulfide bridges.

Quaternary Structure

The structure formed when multiple polypeptide chains associate together, such as in hemoglobin.

Denaturation

The process by which a protein loses its shape and function due to changes in temperature, pH, or salt concentration.

Surface Area-to-Volume Ratio

A critical ratio for cell efficiency; as a cell grows, its volume increases faster than its surface area, which decreases the efficiency of nutrient and waste exchange.

Fluid Mosaic Model

A model describing the plasma membrane as a fluid structure where phospholipids and proteins move laterally.

Selective Permeability

The property of the plasma membrane that allows small nonpolar molecules to pass easily while requiring transport proteins for ions and large polar molecules.

Water Potential Formula

$$\Psi = \Psi_p + \Psi_s$$

Solute Potential Formula

$$\Psi_s = -iCRT$$

Tonicity

A comparison of solute concentrations inside and outside a cell that determines the direction of water movement.

Plasmolysis

The shrinking of a plant cell membrane away from the cell wall when placed in a hypertonic solution.

Sodium-Potassium Pump (Na+/K+ pump)

A primary active transport mechanism that uses ATP to move $3\,Na^+$ out of the cell and $2\,K^+$ into the cell.

Endocytosis

The bulk transport process of moving material into a cell via vesicle formation; including phagocytosis (solids) and pinocytosis (liquids).

First Law of Thermodynamics

The law stating that energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

The law stating that every energy transfer increases the entropy (disorder) of the universe.

Exergonic Reactions

Chemical reactions that release energy, where products have less free energy than reactants, such as ATP hydrolysis.

Endergonic Reactions

Chemical reactions that require an input of energy, where products have more free energy than reactants.

Enzymes

Biological catalysts that speed up reactions by lowering the activation energy without being consumed in the process.

Induced Fit

The phenomenon where an enzyme changes its shape slightly upon substrate binding to enhance the catalytic reaction.

Competitive Inhibition

Regulation where an inhibitor competes with the substrate for the active site of an enzyme; it can be overcome by increasing substrate concentration.

Noncompetitive Inhibition

Regulation where an inhibitor binds to an allosteric site, changing the enzyme's shape and preventing the substrate from binding effectively.

Feedback Inhibition

A regulatory mechanism where the end product of a metabolic pathway inhibits an upstream enzyme to prevent the overproduction of resources.

Photosynthesis Equation

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

Rubisco

The enzyme responsible for fixing carbon dioxide in the Calvin cycle; it can also bind oxygen in a wasteful process called photorespiration.

Cellular Respiration Equation

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$$

Final Electron Acceptor

During the electron transport chain of aerobic respiration, oxygen acts as the final electron acceptor to form water.

Fermentation

An anaerobic process that allows glycolysis to continue by regenerating $NAD^+$; produces either lactic acid or ethanol and $CO_2$.

Ligand

A specific signaling molecule that binds to a receptor to initiate a cellular response.

Signal Amplification

A process where a single ligand binding to a receptor triggers a cascade that activates many molecules, leading to a large cellular response.

Homeostasis

The maintenance of stable internal conditions, often regulated through negative feedback loops.

Checkpoints

Regulatory points in the cell cycle (G1, G2, M) that ensure the cell is ready to proceed to the next phase.

Apoptosis

Programmed cell death that occurs if a cell's DNA damage is too severe to repair.

Proto-oncogenes

Normal genes that promote cell division; when mutated, they become oncogenes that can cause cancer.

Tumor Suppressor Genes

Genes that slow or stop cell division, such as p53; loss of function through mutation can lead to uncontrolled cell growth.

Law of Segregation

Mendel's law stating that allele pairs separate during gamete formation, so each gamete receives only one allele for each gene.

Law of Independent Assortment

Mendel's law stating that alleles of different genes separate independently of one another during gamete formation, provided the genes are on different chromosomes.

Incomplete Dominance

An inheritance pattern where the heterozygote exhibits a blended phenotype (e.g., pink flowers from red and white parents).

Codominance

An inheritance pattern where both alleles are fully and distinctly expressed in the heterozygote (e.g., AB blood type).

Phenotypic Plasticity

The ability of one genotype to produce different phenotypes in response to different environmental conditions.

Linked Genes

Genes located close together on the same chromosome that tend to be inherited together and do not follow the law of independent assortment.

X-Inactivation

The random inactivation of one X chromosome in female mammals, which forms a dense structure called a Barr body.

Nondisjunction

The failure of chromosomes or sister chromatids to separate properly during meiosis, resulting in aneuploidy (e.g., Trisomy 21).

Semiconservative Replication

The mechanism of DNA replication where each new double helix consists of one original (template) strand and one newly synthesized strand.

Helicase

The enzyme responsible for unwinding the DNA double helix by breaking hydrogen bonds at the replication fork.

Okazaki fragments

Short segments of DNA synthesized discontinuously on the lagging strand during DNA replication.

Central Dogma

The concept describing the flow of genetic information: $\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$.

Splicing

The post-transcriptional process in eukaryotes where non-coding introns are removed and coding exons are joined together.

Alternative Splicing

A process that allows different combinations of exons to be joined from a single pre-mRNA, resulting in multiple distinct proteins from one gene.

Operons

Gene regulation systems in prokaryotes, such as the Lac operon (inducible) and the Trp operon (repressible).

Hox genes

A specific type of homeotic gene that controls the identity of body segments during development.

Point Mutations

Changes in a single DNA base pair; types include silent (no amino acid change), missense (different amino acid), and nonsense (early stop codon).

Retrovirus

An RNA virus, such as HIV, that uses the enzyme reverse transcriptase to copy its RNA genome into DNA.

PCR (Polymerase Chain Reaction)

A biotechnology technique used to rapidly amplify specific segments of DNA.

Gel Electrophoresis

A method used to separate DNA fragments by size; since DNA is negatively charged, it moves toward the positive electrode, with smaller fragments moving faster.

Fitness

A measure of an organism's reproductive success, defined by its ability to pass genes to the next generation.

Genetic Drift

Random changes in allele frequencies that have the strongest effect in small populations; includes the bottleneck and founder effects.

Allopatric Speciation

The formation of new species that occurs when a population is geographically isolated.

Sympatric Speciation

The formation of new species without geographic separation, often occurring through polyploidy in plants.

Hardy-Weinberg Equilibrium Equations

$p + q = 1$ and $p^2 + 2pq + q^2 = 1$

Miller-Urey Experiment

A landmark experiment that simulated early Earth conditions and proved that organic molecules could be produced from inorganic precursors.

RNA World Hypothesis

The theory that RNA was the first genetic molecule because it can both store information and catalyze chemical reactions.

Pheromones

Chemical signals used for communication between members of the same species.

Altruism

Behavior that decreases an individual's fitness but increases the fitness of others in the group; it can evolve if it increases inclusive fitness.

10% Rule

The ecological rule stating that only approximately $10\%$ of the energy from one trophic level is transferred to the next.

Net Primary Productivity (NPP)

The energy remaining in an ecosystem after producers have used what they need for respiration ($\text{NPP} = \text{GPP} - R$).

Nitrogen fixation

The process of converting atmospheric nitrogen ($N_2$) into a form that plants can use (e.g., ammonium.

Carrying Capacity

The maximum population size that a particular environment can sustainably support.

Keystone Species

A species that has a disproportionately large effect on its ecosystem structure relative to its abundance.

Ecological Succession

The predictable process of community change over time; includes primary succession (no soil initially) and secondary succession (soil remains).

Simpson’s Diversity Index

A formula used to measure the biodiversity and evenness of species within a community.

Biomagnification

The process where toxins become increasingly concentrated in the tissues of organisms at higher trophic levels.

Greenhouse Effect

The process by which greenhouse gases like $CO_2$ and $CH_4$ trap heat in the atmosphere, warming the planet.