Biology Lecture Reviewhttps://chat.openai.com/

Key Concepts of Biochemistry and Cell Biology

  • Tertiary Structure of Proteins

    • Interactions involved:
    • Hydrophobic interactions: Non-polar side chains fold away from water.
    • Disulfide bonds: Covalent bonds between cysteine residues.
    • Hydrogen bonding: Between polar side chains and backbone.
    • Ionic bonding: Between negatively and positively charged side chains.

  • Enzyme Composition

    • Holoenzyme: Complete, active enzyme complex.
    • Apoenzyme: Inactive protein part needing a cofactor.
    • Cofactor: Non-protein molecule assisting enzyme function.
    • Coenzymes: Organic cofactors, e.g., vitamins.
    • Inorganic cofactors: Typically metal ions.
    • Prosthetic groups: Tightly or covalently bonded cofactors.

  • Enzyme Activity

    • Phosphorylase: Directly adds phosphate by breaking substrate bonds.
    • Kinase: Transfers phosphate group from an ATP molecule.

  • Protein Types

    • Integral Proteins: Function in transport and signaling across membranes.
    • Peripheral Proteins: Involved in receptor activities and cell recognition.

  • Cytosis

    • Circular transport of large molecules across membranes (active transport).
    • Receptor-mediated endocytosis: Uses receptor proteins and clathrin for vesicle formation, requires energy.

Cellular Structures and Functions

  • Ribosomes

    • Not considered organelles.
    • Free ribosomes synthesize proteins for the cytosol; ribosomes on the Rough ER synthesize proteins for export.

  • Endomembrane System

    • Includes nucleus, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vacuoles, and the cell membrane.
    • Nuclear Envelope: Double bilayer with perinuclear space.
    • Rough ER: Continuous with nuclear envelope; modifies proteins synthesized by ribosomes.
    • Smooth ER: Synthesizes lipids, detoxifies, and produces steroid hormones.

  • Proteasome: Degrades proteins tagged with ubiquitin.

  • Central Vacuoles: Large in plants for storage and rigidity (tonoplast).

  • Peroxisomes: Contain catalase to detoxify hydrogen peroxide.

  • Mitochondrial Inheritance: Maternal inheritance only.

Cell Junctions and Matrix

  • Cell Junctions
    • Gap junctions: Allow communication and transport between animal cells.
    • Desmosomes: Provide structural support against mechanical stress.
    • Tight junctions: Prevent leakage of substances between cells.

Cell Metabolism and Enzyme Regulation

  • Bioenergetics

    • Glycolysis:
    • Glucose → 2 ATP + 2 NADH + 2 Pyruvate.
    • Krebs Cycle:
    • Pyruvate → CO2 + NADH + acetyl-CoA; acetyl-CoA enters Krebs → 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP.

  • Enzyme Regulation

    • Genetic: e.g., lac operon, Physical, Enzyme modification.

Photosynthesis

  • Chloroplast Structure
    • Thylakoids: Site for light reactions (ETC occurs here).
    • Stroma: Site for Calvin cycle occurring.

Human Anatomy and Physiology

  • Liver Functions
    • Detoxification, blood glucose regulation, protein synthesis.
    • Produces bile, facilitating fat digestion.

Immune System Basics

  • White Blood Cells:

    • Neutrophils: First responders to infection.
    • Macrophages: Large phagocytes that aggregate at infection sites.

  • T Cells and B Cells:

    • Cytotoxic T-cells: Destroy infected cells.
    • Helper T-cells: Activate B-cells and macrophages.

  • Antibodies (Immunoglobulins): Essential for identifying pathogens and neutralizing them (Ig types A, D, E, G, M).

Evolutionary Concepts

  • Natural Selection
    • Mechanisms: Stabilizing, disruptive, directional.
  • Genetic Equilibrium Requirements
    • No mutations, natural selection, gene flow, large population, random mating.

Animal Behavior Classification

  • Fixed Action Patterns (FAPs): Innate behaviors triggered by specific stimuli.
  • Imprinting: Learning during a critical period.

Plant Structure and Growth

  • Xylem and Phloem: Transport water and nutrients.
  • Plant Hormones:
    • Auxins: Regulate plant growth direction towards light.
    • Cytokinins: Promote cell division.
    • Gibberellins: Influence flowering and fruiting processes.

Summary Points for Exam Preparation

  • Understand key concepts in cell and molecular biology, including structure-function relationships, cellular metabolism, genetic information regulation, and basic principles of human anatomy and physiology.
  • Remember the examples that illustrate key biochemical pathways, cellular structures and functions, and essential roles of organelles and biochemical agents (enzymes, hormones).
  • Key evolutionary principles and how they relate to genetic diversity, adaptation, and the interaction between species in their environments.
  • Comprehend the basics of animal behavior, ecology, and fundamental genetics for a comprehensive understanding of biology topics relevant to the exam.