AP Biology Ultimate Guide Notes

Unit 1: Chemistry of Life

Elements

• Elements: Substances that cannot be broken down by chemical means.
• Key elements in biology: Oxygen, Carbon, Hydrogen, Nitrogen.
• Trace elements (small quantities): Iron, Iodine, Copper.

Subatomic Particles

• Atoms: Building blocks of matter.
  • Protons (+), Neutrons (neutral), Electrons (-).
• Isotopes: Same number of protons, different neutrons.

Compounds

• Consist of two or more elements.
• Chemical bonds: Ionic, Covalent, Hydrogen.
• Ionic bonds: Electron transfer.
• Covalent bonds: Electron sharing (polar & non-polar).

Water: The Versatile Molecule

• Hydrogen bonds contribute to cohesion, adhesion, surface tension, high heat capacity, expansion on freezing.
• Capillary action: Water rising in plant structures.
• Surface tension: Tension on water surface.

Acids and Bases

• Solutions can be acidic, basic, or neutral.
• pH scale: Measures acidity/alkalinity (1-14).
• pH = log [H+]; logarithmic scale.

Organic Molecules

• Carbon: Versatile atom bonding with various elements.
• Polymers & Monomers: Chains & building blocks of macromolecules.
• Four main organic compounds: Carbohydrates, Proteins, Lipids, Nucleic Acids.

Carbohydrates

• Ratio of C:H:O is approximately 1:2:1.
• Types: Monosaccharides, Disaccharides, Polysaccharides.

Proteins

• Amino acids: Building blocks, 20 types.
• Structure levels: Primary, Secondary, Tertiary, Quaternary.

Lipids

• Non-polar molecules: Triglycerides, Phospholipids, Steroids.
• Structural: Cell membranes, energy storage.

Nucleic Acids

• DNA & RNA: Hereditary material and protein synthesis.

Unit 2: Cell Structure and Function

Types of Cells

• Prokaryotic Cells: Simpler, no membrane-bound organelles (e.g., bacteria).
• Eukaryotic Cells: More complex, contain organelles (e.g., plants, animals).

Organelles

• Nucleus: Control center, contains DNA.
• Ribosomes: Sites of protein synthesis.
• ER (Endoplasmic Reticulum): Rough (with ribosomes) & Smooth (lipid synthesis).
• Golgi Apparatus: Modifies, sorts, packages proteins.
• Mitochondria: Powerhouse, ATP production.
• Lysosomes: Digestive enzymes.
• Vacuoles: Storage sacs.

Transport Across Membranes

• Passive Transport: Diffusion, Osmosis.
• Active Transport: Requires energy (ATP).
• Endocytosis & Exocytosis: Bulk transport mechanisms.

Unit 3: Cellular Energetics

Bioenergetics

• Study of energy flow in biological systems.

Thermodynamics

• First Law: Energy conservation.
• Second Law: Energy transfers increase disorder.

Enzymes

• Biological catalysts, lower activation energy.
• Specificity: Catalyze specific reactions.
• Factors affecting enzyme activity: Temperature, pH, concentration.

ATP

• Adenosine Triphosphate: Energy currency.
• Production via cellular respiration (aerobic & anaerobic).

Photosynthesis

• Conversion of light energy to chemical energy (6CO2 + 6H2O -> C6H12O6 + 6O2).
• Light-dependent & light-independent reactions.

Chloroplasts

• Site of photosynthesis, contain chlorophyll.

Cellular Respiration

• Aerobic: Glycolysis, Krebs Cycle, Electron Transport Chain.
• Anaerobic: Fermentation.

Unit 4: Cell Communication and Cell Cycle

Cell Communication

• Signal transduction: External signals to cellular responses.
• Membrane receptors: Ligand-gated, Enzyme-linked, G-protein.

Cell Cycle

• Interphase (G1, S, G2) & Mitosis (Prophase, Metaphase, Anaphase, Telophase).
• Regulation: Cyclins and CDKs.

Cancer

• Uncontrolled cell growth due to oncogenes.

Unit 5: Hereditary

Genetics

• Gregor Mendel's laws: Dominance, Segregation, Independent Assortment.
• Punnett squares for predicting offspring traits.

Non-Mendelian Genetics

• Linked genes violate independent assortment.
• Sex-linked traits: X-linked inheritance.

Meiosis

• Produces gametes, increases genetic variability.
• Phases: Meiosis I & II.

Unit 6: Gene Expression and Regulation

DNA & RNA

• DNA: Double helix, genetic blueprint.
• RNA: Single-stranded, roles in transcription & translation.

Transcription & Translation

• DNA transcribed to RNA; RNA translated to proteins.

Mutations

• Point mutations (nonsense, missense, silent).
• Gene rearrangements (insertions, deletions, duplications).

Unit 7: Natural Selection

Evolution

• Natural selection: Survival of the fittest.
• Darwin's observations and evidence for evolution.

Genetic Variability

• Importance for natural selection.

Speciation

• Formation of new species via reproductive isolation.

Unit 8: Ecology

Interactions & Succession

• Relationships between organisms (mutualism, commensalism, parasitism).
• Ecological succession: Change in communities over time.

Human Impact

• Effects on environment: Greenhouse effect, pollution, biodiversity loss.