Chapter 5: The Structure and Function of Large Biological Molecules

Overview of Macromolecules

Macromolecules are large, complex molecules essential for life, including carbohydrates, lipids, proteins, and nucleic acids. Each class has unique structures and functions.

• Macromolecule Classes: Carbohydrates, lipids, proteins, nucleic acids.

• Monomers and Polymers: Monomers are small building blocks; polymers are long chains of monomers.

• Dehydration Synthesis and Hydrolysis: Dehydration synthesis joins monomers by removing water; hydrolysis breaks polymers by adding water.

Carbohydrates

• Functions: Energy storage (e.g., glucose), structural support (e.g., cellulose in plants).

• Types: Monosaccharides (simple sugars), disaccharides, polysaccharides (complex carbs).

Lipids

• Types: Fats (triglycerides), phospholipids, steroids.

• Triglyceride Structure: Glycerol + 3 fatty acids.

• Phospholipids: Major component of cell membranes; have hydrophilic heads and hydrophobic tails.

Proteins

• Structure: Polymers of amino acids; structure levels: primary, secondary, tertiary, quaternary.

• Function: Enzymes, structural support, transport, signaling, defense.

• Shape and Function: Protein shape determines its function; denaturation disrupts function.

Nucleic Acids

• Types: DNA and RNA.

• Structure: Polymers of nucleotides; DNA is double-stranded, RNA is usually single-stranded.

• Comparison: Both store genetic information, but differ in sugar, bases, and structure.

Chapter 6: Tour of the Cell

Cell Theory and Types

The cell is the basic unit of life. All living organisms are composed of cells, which can be prokaryotic or eukaryotic.

• Cell Theory: All living things are made of cells; cells are the basic unit of structure and function; all cells come from pre-existing cells.

• Prokaryotic vs. Eukaryotic Cells: Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have both.

Cell Structure and Function

• Plant vs. Animal Cells: Plant cells have cell walls, chloroplasts, and large central vacuoles; animal cells do not.

• Organelles: Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, chloroplasts (plants), etc.

• Endomembrane System: Includes nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, and plasma membrane.

• Cytoskeleton: Microfilaments, intermediate filaments, microtubules; provide structure and facilitate movement.

• Cell Junctions: Tight junctions, desmosomes, gap junctions (animals); plasmodesmata (plants).

Chapter 7: Membrane Structure and Function

Cell Membrane Structure

The cell membrane is a selectively permeable barrier composed mainly of a phospholipid bilayer with embedded proteins.

• Phospholipid Bilayer: Hydrophilic heads face outward; hydrophobic tails face inward.

• Membrane Proteins: Integral and peripheral proteins serve in transport, signaling, and structural support.

Membrane Transport

• Passive Transport: Diffusion, osmosis, facilitated diffusion (no energy required).

• Osmosis: Diffusion of water across a membrane.

• Hypertonic, Hypotonic, Isotonic: Terms describe relative solute concentrations and water movement.

• Active Transport: Movement against concentration gradient; requires energy (e.g., sodium-potassium pump).

• Bulk Transport: Endocytosis (phagocytosis, pinocytosis, receptor-mediated), exocytosis.

Chapter 8: Introduction to Metabolism

Energy and Thermodynamics

Metabolism encompasses all chemical reactions in a cell, governed by the laws of thermodynamics.

• Energy Types: Kinetic, potential, chemical, thermal.

• First Law of Thermodynamics: Energy cannot be created or destroyed.

• Second Law of Thermodynamics: Entropy (disorder) increases in spontaneous processes.

• ATP: Main energy currency; couples exergonic and endergonic reactions.

• Enzymes: Biological catalysts that lower activation energy and speed up reactions.

Chapter 9: Cellular Respiration and Fermentation

Overview of Cellular Respiration

Cellular respiration is the process by which cells extract energy from glucose to produce ATP, involving glycolysis, the citric acid cycle, and oxidative phosphorylation.

• Overall Equation:

• Stages: Glycolysis, citric acid cycle (Krebs cycle), oxidative phosphorylation (electron transport chain and chemiosmosis).

• ATP Production: Most ATP is produced during oxidative phosphorylation.

• Fermentation: Anaerobic process; produces less ATP than aerobic respiration.

• Substrate-level vs. Oxidative Phosphorylation: Substrate-level occurs in glycolysis and citric acid cycle; oxidative in electron transport chain.

• Strict vs. Facultative Anaerobes: Strict anaerobes cannot survive in oxygen; facultative can use either aerobic or anaerobic pathways.

Comparison Table: Aerobic Respiration vs. Fermentation

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