AP Biology Exam Review Notes

Macromolecules Required by Living Organisms:
- Four main types: Proteins, Lipids, Carbohydrates, Nucleic Acids.
- Functions:
- Proteins: Enzymatic activity, structural support, transport, signaling.
- Lipids: Energy storage, membrane structure, signaling molecules.
- Carbohydrates: Energy source, structural components (cellulose in plants).
- Nucleic Acids: Genetic information storage and transfer (DNA & RNA).
Elemental Composition:
- Carbohydrates: Contain carbon (C), hydrogen (H), and oxygen (O).
- Proteins: Composed of elements C, H, O, nitrogen (N), and sulfur (S).
- Nucleic Acids: Contain C, H, O, N, and phosphorus (P).
- Lipids: Primarily C and H, may include O and P.
Protein Structure:
- Amino acids (the monomers of proteins) contain an R group, which determines the properties and folding of the protein.
- Polar R groups: Hydrophilic, tend to fold outward.
- Nonpolar R groups: Hydrophobic, tend to fold inward.
Formation & Breakdown:
- Dehydration: Process of joining monomers, i.e., forming polymers (e.g., combining two amino acids to form a dipeptide).
- Hydrolysis: Breakdown of polymers into monomers (e.g., breaking down proteins into amino acids).

Properties of Monomers:
- Carbohydrate monomers: Monosaccharides (e.g., glucose).
- Protein monomers: Amino acids, linked by peptide bonds.
- Nucleic acid monomers: Nucleotides, connected by phosphodiester bonds.
Bonds:
- Carbohydrates: Glycosidic bonds join monosaccharides.
- Proteins: Peptide bonds link amino acids.
- Nucleotides: Phosphodiester bonds connect nucleotides.

Macromolecular Structure:
- Carbohydrates: Starch (energy storage, alpha bonds) vs. Cellulose (structural, beta bonds).
- Proteins: Complex structures (primary to quaternary levels), with various types of bonding (hydrogen, ionic, and disulfide bonds).
- Nucleic Acids: Differences between DNA (deoxyribose, thymine) and RNA (ribose, uracil).

Impact of Change in Subunits:
- Mutations in nucleic acid sequence can alter protein structure and function (e.g., base substitutions).
- Protein folding is critical; misfolded proteins can lead to loss of function (e.g., prions).

Structure and Differences:
- DNA vs. RNA: Structure, sugar differences (deoxyribose in DNA; ribose in RNA), and nitrogenous bases.

Organelle Functions:
- Ribosomes: Protein synthesis.
- Endoplasmic Reticulum (ER): Rough ER (ribosome-studded, protein synthesis) vs. Smooth ER (lipid synthesis).
- Golgi Apparatus: Processing and packaging proteins.
- Mitochondria: ATP production.
- Lysosomes: Digestion and waste processing.

Fluid Mosaic Model:
- Phospholipid bilayer with embedded proteins; selectively permeable.
Membrane Functionality: Maintains homeostasis and facilitates transport.

Types of Transport:
- Passive (no energy, with gradient) vs. Active (requires energy, against gradient).
- Endocytosis (bulk uptake) and Exocytosis (bulk secretion).

Enzyme Structure:
- Active site for substrate binding; affected by temperature and pH.
Metabolism:
- Glycolysis, Krebs cycle, and electron transport chain; energy release and storage.

Light-dependent Reactions: Convert solar energy into chemical energy (NADPH, ATP).
Calvin Cycle: Utilizes ATP and NADPH to synthesize glucose from CO2.