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Overview of AQA GCSE Biology Paper 1

May 2, 2025

AQA GCSE Biology Paper 1 Overview

This lecture covers key topics for the AQA GCSE Biology Paper 1, relevant for higher and foundation tiers, double combined trilogy, and triple/separate biology. Topics include cells, organization, infection and response, and bioenergetics. Important distinctions for triple biology are noted, while higher tier specifics are not as emphasized.

Cells

  • Basic Understanding: All life consists of cells, visible with a light microscope (nucleus) and electron microscope (organelles).
  • Microscopy: Higher resolution and resolving power with electron microscopes.
  • Cell Size Calculation: Actual size = Image size / Magnification.

Types of Cells

  • Eukaryotic Cells: Have a nucleus (e.g., plant and animal cells).
  • Prokaryotic Cells: Lack a nucleus.

Cell Structures

  • Cell Membrane: Semi-permeable, controls substance passage.
  • Cell Wall: Provides structure (made of cellulose in plants).
  • Cytoplasm: Site for chemical reactions.
  • Mitochondria: Site of respiration.
  • Ribosomes: Protein synthesis.
  • Chloroplasts: Photosynthesis in plant cells.
  • Vacuole: Stores sap in plant cells.

Triple Biology Exclusive

  • Bacterial Multiplication: Binary fission.
  • Practical: Culture growth and antibiotic testing using aseptic techniques.

DNA and Chromosomes

  • DNA Storage: In chromosomes within eukaryotic cell nuclei.
  • Human Cells: Diploid (23 pairs of chromosomes).
  • Gametes: Haploid (23 single chromosomes).
  • Cell Division by Mitosis:
    • Genetic material duplicates.
    • Chromosomes pulled to opposite sides.
    • Two identical cells formed.

Specialized Cells and Stem Cells

  • Specialization: Cells adapt based on function (nerve, muscle, etc.).
  • Stem Cells: Capable of specialized functions; found in embryos, marrow, and meristem of plants.
  • Stem Cell Applications: Treatments for diabetes, paralysis, and cloning for organ harvesting.

Transport in Cells

  • Diffusion: Passive movement from high to low concentration.
  • Osmosis: Diffusion of water across a semi-permeable membrane.
  • Active Transport: Energy used to move substances against a concentration gradient.

Organization

  • Tissues: Groups of similar cells.
  • Organs and Systems: Organs form systems (e.g., circulatory system).

Digestive System

  • Function: Breaks down food into nutrients.
  • Key Components:
    • Stomach: Acid breaks down food.
    • Small Intestine: Bile and enzymes aid in digestion.

Enzymes

  • Role: Biological catalysts breaking down molecules.
  • Specificity: Work through "lock and key" principle.
  • Factors Affecting Activity: Temperature and pH.

Respiratory System and Circulation

  • Breathing vs. Respiration: Breathing supplies oxygen for cellular respiration.
  • Heart Functionality: Double circulatory system.
  • Blood Circulation: Arteries (oxygenated blood), veins (deoxygenated blood).

Diseases

  • Non-communicable Diseases:
    • Causes: Obesity, diet, smoking, alcohol.
  • Communicable Diseases:
    • Caused by pathogens (viruses, bacteria, fungi).

Infection and Immunity

  • Body's Defenses: Skin, mucus, white blood cells.
  • Vaccines: Introduce inactive pathogens to boost immunity.

Bioenergetics

  • Photosynthesis: Conversion of light into chemical energy in plants.
  • Respiration: Aerobic (with oxygen) and anaerobic (without oxygen).
  • Metabolism: Sum of all chemical reactions in cells.

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