Chapter 5: Macromolecules

Overview of Macromolecules

Macromolecules are large, complex molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids. They are built from smaller units called monomers.

• Four Main Classes: Carbohydrates, proteins, lipids, nucleic acids.

• Polymer: A long molecule consisting of many similar or identical building blocks linked by covalent bonds.

• Monomers: The repeating units that serve as building blocks of a polymer (e.g., monosaccharides, amino acids, nucleotides).

• Dehydration Synthesis: A chemical reaction that builds polymers by removing water.

• Hydrolysis: A chemical reaction that breaks polymers into monomers by adding water.

Carbohydrates

• Function: Energy storage and structural support.

• Types: Monosaccharides (glucose), disaccharides (sucrose), polysaccharides (starch, cellulose).

Lipids

• Function: Energy storage, membrane structure, signaling.

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

• Triglyceride Structure:

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

Proteins

• Function: Enzymatic, structural, transport, signaling, defense.

• Structure: Composed of amino acids; structure determines function.

• Levels of Structure: Primary, secondary, tertiary, quaternary.

• Shape and Function: Protein shape is determined by amino acid sequence and interactions; shape is critical for function.

Nucleic Acids

• Function: Store and transmit genetic information.

• Types: DNA and RNA.

• Comparison: Both are polymers of nucleotides; DNA is double-stranded, RNA is single-stranded.

Chapter 6: Tour of the Cell

Cell Theory and Cell Types

The cell theory states that all living things are composed of cells, which are the basic units of life. Cells can be prokaryotic or eukaryotic.

• Plasma Membrane: Separates cell from environment; controls movement of substances.

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

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

Cell Organelles and Functions

• Nucleus: Contains genetic material; controls cell activities.

• Endomembrane System: Includes nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and vesicles.

• Mitochondria: Site of cellular respiration; produces ATP.

• Chloroplasts: Site of photosynthesis in plant cells.

• Cytoskeleton: Provides structural support; includes microfilaments, intermediate filaments, microtubules.

Cell Surface Structures

• Cilia and Flagella: Structures for movement.

• Extracellular Matrix: Network outside animal cells; provides support and regulates behavior.

• Cell Junctions: Connections between cells; include tight junctions, anchoring junctions, gap junctions.

• Plasmodesmata: Channels between plant cells for communication.

Chapter 7: Membrane Structure and Function

Cell Membrane Structure

Cell membranes are composed of a phospholipid bilayer with embedded proteins, carbohydrates, and cholesterol, providing selective permeability and fluidity.

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

• Membrane Proteins: Integral and peripheral proteins serve as channels, receptors, and enzymes.

Membrane Function

• Passive Transport: Movement of substances without energy input (diffusion, osmosis, facilitated diffusion).

• Osmosis: Diffusion of water across a membrane.

• Hypertonic, Hypotonic, Isotonic Solutions: Describe relative solute concentrations and water movement.

• Active Transport: Movement of substances against concentration gradient using energy (ATP).

• Endocytosis and Exocytosis: Bulk transport of materials into and out of the cell.

Chapter 8: Introduction to Metabolism

Metabolic Concepts

Metabolism encompasses all chemical reactions in a cell, including energy transformation and matter cycling.

• Kinetic Energy: Energy of motion.

• Potential Energy: Stored energy.

• Thermodynamics: Laws governing energy transfer.

  • First Law: Energy cannot be created or destroyed.

  • Second Law: Every energy transfer increases entropy.

• ATP: Main energy currency of the cell; transfers energy via phosphate groups.

• Enzymes: Biological catalysts that speed up reactions by lowering activation energy.

Equations

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. It consists of glycolysis, the citric acid cycle, and oxidative phosphorylation.

• General Equation:

• Glycolysis: Occurs in cytoplasm; breaks glucose into pyruvate.

• Citric Acid Cycle: Occurs in mitochondria; completes breakdown of glucose.

• Oxidative Phosphorylation: Includes electron transport chain and chemiosmosis; produces most ATP.

• NADH and FADH2: Electron carriers that transfer electrons to the electron transport chain.

• Fermentation: Anaerobic process that allows ATP production without oxygen; produces lactic acid or ethanol.

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

• Use of Fats and Proteins: Can be metabolized for energy via cellular respiration.

Comparison Table: Aerobic vs. Anaerobic Respiration

Additional info: Some explanations and examples have been expanded for clarity and completeness.