AP Biology Lecture Notes

Introduction

• AP Bio exam is challenging; preparation involves understanding every unit and topic.
• Glenn Wokenfeld, also known as Mr. W, provides a comprehensive review.
• Checklist available for exam preparation.

Unit 1: Chemistry of Life

Properties of Water

• Polar Molecule: Unequal electron sharing; hydrogen bonds are intermolecular.
• Hydrogen Bonds: Weaker than covalent or ionic; essential in DNA, RNA, proteins.

Key Properties from Hydrogen Bonding

• Cohesion: Water molecules stick together; high heat of vaporization, high specific heat, high surface tension.
• Adhesion: Water sticks to other substances, aids in transpiration in plants.
• Surface Tension: Water molecules create a net on surfaces.

pH and Solutions

• Acidic Solutions: More hydrogen ions, pH below 7.
• Basic Solutions: More hydroxide ions, pH above 7.
• Elements Essential for Life: CHNOPS (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur).

Biomolecules

• Monomers and Polymers: Carbohydrates, proteins, nucleic acids built from monomers.
• Dehydration Synthesis: Binds monomers by removing water.
• Hydrolysis: Breaks polymers by adding water.

Functional Groups

• Phosphate Groups: Key for energy in ATP.
• Methyl Groups: Silences DNA.
• Hydroxy and Carbonyl Groups: Make molecules hydrophilic.

Macromolecules

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides.
• Lipids: Non-polar, used for energy storage, structure (cell membranes), signaling (hormones).

Unit 2: Cell Structure and Function

Cell Types

• Prokaryotic Cells: Simple structure, no nucleus, circular DNA.
• Eukaryotic Cells: Complex, nucleus, linear DNA, organelles.

Cell Size and Surface Area

• Cells maintain a high surface area to volume ratio for efficient nutrient and waste exchange.

Compartmentalization

• Advantages: Distinct internal environments, surface area for reactions.
• Endomembrane System: Includes ER, Golgi, lysosomes.
• Endosymbiosis Theory: Origin of mitochondria and chloroplasts.

Membrane Structure

• Fluid Mosaic Model: Phospholipid bilayer with proteins, cholesterol.
• Transport: Diffusion, osmosis, active transport.

Unit 3: Cellular Energetics

Enzymes

• Catalysts: Lower activation energy, specific to substrates.
• Factors Affecting Activity: pH, temperature, concentration.

Cellular Respiration

• Process: Glycolysis, Krebs cycle, ETC.
• ATP Production: Through chemiosmosis and substrate-level phosphorylation.

Photosynthesis

• Light Reactions: Convert light to chemical energy (ATP, NADPH).
• Calvin Cycle: Uses ATP, NADPH to synthesize carbohydrates.

Unit 4: Cell Communication and Cycle

Signaling

• Direct Contact: Gap junctions, plasmodesmata.
• Ligands: Bind to receptors, initiate signal transduction.

Feedback Mechanisms

• Negative Feedback: Maintains homeostasis.
• Positive Feedback: Drives processes to completion.

Cell Cycle

• Phases: Interphase (G1, S, G2), Mitosis.
• Checkpoints: Ensure readiness for division.

Unit 5: Heredity

Mendelian Genetics

• Principles: Segregation, independent assortment.
• Non-Mendelian: Linked genes, incomplete dominance.

Sex Determination

• Chromosomal Basis: XX/XY systems, environmental factors in reptiles.

Unit 6: Gene Expression and Regulation

DNA Structure

• Double Helix: Bases pair A-T, G-C.
• Replication: Semi-conservative model.

Transcription and Translation

• Central Dogma: DNA → RNA → Protein.
• RNA Processing: Splicing, 5' capping, 3' poly-A tail.

Gene Regulation

• Prokaryotic: Operons (lac, trp).
• Eukaryotic: Enhancers, silencers, epigenetics.

Unit 7: Evolution

Natural Selection

• Mechanisms: Variation, survival of the fittest.
• Evidence: Fossils, homologous structures, molecular data.

Speciation

• Processes: Allopatric, sympatric.
• Adaptive Radiation: Diversification from a common ancestor.

Extinction

• Drivers: Natural, human-induced.
• Impact: Loss of biodiversity, adaptive radiation post-mass extinction.

Unit 8: Ecology

Ecosystems

• Interactions: Food chains, webs, trophic levels.
• Energy Flow: 10% rule, pyramids of energy and biomass.

Population Dynamics

• Growth Models: Exponential, logistic.
• Factors: Carrying capacity, limiting factors.

Conservation

• Biodiversity: Importance, threats from human activity.