AQA GCSE Biology Paper 1 Overview

Introduction

• Covers: Cells, Organisation, Infection and Response, and Bioenergetics.
• Applicable for Higher and Foundation tiers, Combined Trilogy, and Triple Biology.

Cells

Microscope and Cell Structure

• Light Microscope: Visible nucleus; limited subcellular view.
• Electron Microscope: Detailed organelles; better resolution and resolving power.
• Cell Size Calculation: Magnification = Image Size/Object Size.

Cell Types

• Eukaryotic Cells: Have nucleus, e.g., plant and animal cells.
• Prokaryotic Cells: No nucleus, DNA in plasmids.

Cell Organelles

• Cell Membrane: Semi-permeable.
• Cell Wall: Present in plant cells and bacteria; made of cellulose.
• Cytoplasm: Site for chemical reactions.
• Mitochondria: Respiration site.
• Ribosomes: Protein Synthesis.
• Chloroplasts: Photosynthesis in plant cells.
• Permanent Vacuole: Storage in plant cells.

Cell Division and Specialization

• Binary Fission (for triple): Bacteria multiplication.
• Mitosis: Cell growth and repair; produces two identical cells.
• Stem Cells: Unspecialized cells; potential for treating diseases.

Transport in Cells

• Diffusion: Passive movement from high to low concentration.
• Osmosis: Water diffusion across a membrane.
• Active Transport: Energy-required movement against concentration gradient.

Organisation

Tissue and Organs

• Tissues: Groups of similar cells.
• Organs: Made up of tissues.
• Organ Systems: e.g., Circulatory and Digestive systems.

Digestive System

• Breaks down food using acids, bile, and enzymes.
• Enzymes: Biological catalysts, e.g., Amylase, Proteases, Lipases.

Respiratory and Circulatory Systems

• Breathing: Oxygen delivery for respiration.
• Heart and Blood Vessels: Double circulatory system; arteries, veins, capillaries.
• Blood Components: Red/white blood cells, plasma, platelets.

Infection and Response

Pathogens

• Types: Viruses, Bacteria, Fungi, Protists.
• Disease Examples: Measles, HIV, Salmonella, Malaria.

Body Defenses

• Skin, mucus, acid, white blood cells (lymphocytes, phagocytes).
• Vaccination: Immunity through non-infective pathogens.

Antibiotics and Drug Development

• Antibiotics: Kill bacteria; resistance issue.
• Drug Trials: Lab, animal, human trials; blind and double-blind studies.

Bioenergetics

Photosynthesis

• Takes place in chloroplasts.
• Equation: CO2 + H2O → Glucose + Oxygen (Endothermic).
• Limiting Factors: Light, CO2, temperature.

Respiration

• Aerobic Respiration: With oxygen.
• Anaerobic Respiration: Without oxygen; lactic acid production.
• Metabolism: Sum of all cellular reactions.

Practical Applications

• Microscopy: Calculating magnification.
• Osmosis and Diffusion Experiments: Measuring concentration effects.
• Photosynthesis Measurement: Oxygen production trials.