CAPE Biology Unit One Manual - Module One: Cell and Molecular Biology

CAPE Biology Unit One Manual - Module One: Cell and Molecular Biology

Overview of the Module

  • The module is divided into four key topics:

    • Aspects of Biochemistry

    • Cell Structure

    • Membrane Structure and Function

    • Enzymes

Topic 1: Aspects of Biochemistry

  • Discuss the structure and properties of water and its biological significance.

  • Essential macronutrients:

    • Carbohydrates (starch, glucose): Energy release through ATP.

    • Proteins: Growth, repair, and hormone formation.

    • Fats: Energy storage.

  • Water as a predominant molecule (70% of cell mass):

    • Molecular structure: 2 H atoms covalently bonded to O atom, resulting in a polar molecule.

    • Properties of Water:

    • High specific heat capacity, allows temperature regulation.

    • Effective solvent due to its dipole nature.

    • High cohesion aids in mass flow and assists in biological buffering systems.

    • Participation in hydrolysis reactions during digestion/photosynthesis.

Carbohydrates

  • Types of Carbohydrates:

    • Monosaccharides: Simple sugars (e.g., glucose, ribose).

    • Disaccharides: Combinations of two monosaccharides (e.g., sucrose is formed from alpha glucose and beta fructose).

    • Polysaccharides: Complex carbohydrates (e.g., starch, glycogen, cellulose).

    • Key Concepts:

    • Glycosidic bonds formed between sugar units (strong).

    • Reducing vs. Non-reducing sugars; Benedict’s test variability.

Polysaccharides Functions

  • Starch: Energy reserve in plants, digested by amylase.

  • Glycogen: Energy reserve in animals, stored in liver and muscle.

  • Cellulose: Structural support in plant cell walls, resistant to digestion.

Lipids

  • Triglycerides: Composed of three fatty acids and glycerol.

    • Functions: Energy storage, insulation, and hormonal role.

    • Fatty acids classification:

    • Saturated: Solid at room temperature (linked to heart disease).

    • Unsaturated: Liquid at room temperature (healthier).

  • Phospholipids: Key component of cell membranes, amphipathic nature leads to bilayer formation.

Proteins and Amino Acids

  • Amino acids: Building blocks of proteins connected by peptide bonds.

  • Protein Structure Levels:

    • Primary: Linear sequence of amino acids.

    • Secondary: Alpha helices and beta pleated sheets.

    • Tertiary: 3D folding due to interactions between side chains.

    • Quaternary: Multiple polypeptides forming a functional protein (e.g., hemoglobin).

Enzymes

  • Enzymes as biological catalysts, lowering activation energy for biochemical reactions.

  • Specificity and mechanisms (Lock and Key vs. Induced Fit).

  • Factors influencing enzyme activity:

    • Temperature, pH, concentration of enzyme and substrate.

  • Inhibition Mechanisms:

    • Competitive inhibition: Blocks active site.

    • Non-competitive inhibition: Binds elsewhere, altering active site shape; cannot be reversed by increasing substrate.

Topic 2: Cell Structure

  • Differences between plant and animal cells including:

    • Presence of chloroplasts, cell wall, and large vacuoles in plants.

    • Centrioles and smaller temporary vacuoles in animal cells.

  • Functions of key organelles:

    • Nucleus: Contains genetic material and controls cellular activities.

    • Mitochondria: Site for aerobic respiration and ATP production.

    • Chloroplasts: Site of photosynthesis in plant cells.

    • Golgi apparatus, endoplasmic reticulum, and lysosomes involved in protein and waste processing.

Topic 3: Membrane Structure and Function

  • Fluid Mosaic Model: Describes the nature of cell membranes consisting of phospholipids and proteins.

  • Membranes facilitate transport via:

    • Passive transport: Diffusion, facilitated diffusion, and osmosis.

    • Active transport: Requiring ATP to move substances against concentration gradients.

    • Vescular transport: Endocytosis and exocytosis for bulk movement of materials.

Topic 4: Enzymes

  • Importance of enzymes in metabolism and biochemical reactions.

  • Understanding the concept of catalysts and the balance between reaction speed and specificity.

Key Terms and Concepts Summary:

  • Metabolism: All biochemical processes in the body (anabolism and catabolism).

  • Hydrolysis and Condensation: Breakage and formation of bonds involving water.

  • Gene and Chromosome Mutations: Implications for genetic stability and variation.

  • Natural Selection: Process driving evolution through environmental pressures.

  • Contraceptive Methods: Various hormonal and non-hormonal methods derived from reproductive biology knowledge.