AP Biology Review: Key Concepts and Processes

Cohesion of Water

Water molecules stick due to hydrogen bonding.

Surface Tension

Allows small organisms to walk on water.

High Specific Heat

Stabilizes aquatic temperatures and moderates climates.

Evaporative Cooling

Prevents overheating in organisms and ecosystems.

Freezing Point Expansion

Ice floats, insulating aquatic life in winter.

Polarity of Water

Dissolves ionic and polar substances effectively.

Hydration Shells

Form around solutes, aiding nutrient transport.

pH Scale

Measures hydrogen ion concentration; logarithmic scale.

Acids

Increase H⁺ concentration by adding protons.

Bases

Decrease H⁺ by removing protons or releasing OH⁻.

Water's Bent Shape

Creates polarity due to electronegativity difference.

Hydrogen Bonds

Form between water molecules and polar substances.

Characteristics of Living Things

Cells, energy use, growth, reproduction, response, homeostasis.

Scientific Method Steps

Question, research, hypothesis, experiment, analyze, conclude.

Carbohydrates

Provide energy and structure (e.g., glucose).

Lipids

Store energy, insulation, and form membranes.

Nucleic Acids

Store genetic information (DNA, RNA).

Proteins

Catalyze reactions, provide structure, transport materials.

Animal Cell Structures

Nucleus, mitochondria, ribosomes, ER, Golgi, lysosomes.

Plant vs. Animal Cells

Plant cells have walls, chloroplasts; animal cells do not.

Surface Area-to-Volume Ratio

Limits nutrient and waste transport in cells.

Fluid Mosaic Model

Phospholipid bilayer with embedded proteins.

Phospholipid Head

Hydrophilic, polar, interacts with water.

Phospholipid Tail

Hydrophobic, nonpolar, faces inward.

Passive Transport

Moves substances without energy (e.g., diffusion).

Active Transport

Uses energy to move substances against gradients.

Eukaryotic vs. Prokaryotic Cells

Eukaryotic have nucleus; prokaryotic do not.

Ecological Hierarchy

Atoms to biosphere: organization of life.

Natural Cycles

Hydrological, carbon, nitrogen, phosphorus, oxygen, sulfur.

Role of Decomposers

Recycle nutrients by breaking down waste.

Symbiotic Relationships

Mutualism, commensalism, parasitism define interactions.

Exponential Growth

Rapid population increase, J-shaped curve.

Carrying Capacity

Maximum sustainable population size in an environment.

Food Chains vs. Food Webs

Chains are linear; webs are interconnected.

Ecological Succession

Ecosystem changes over time; primary and secondary.

Cell Theory

Cells are life's basic units; arise from existing cells.

Common Cell Components

Cell membrane, cytoplasm, genetic material.

Functional Groups

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate.

Isomers

Same formula, different structures; types include structural.

Condensation Reaction

Joins monomers by removing water, forming bonds.

Polymerization in Proteins

Ribosomes link amino acids with peptide bonds.

DNA vs. RNA

DNA is double-stranded; RNA is single-stranded.

Similarities of DNA and RNA

Both are nucleic acids carrying genetic information.