AQA GCSE Biology Paper 1 Overview

Covers:

• Higher and Foundation Tier
• Double Combined Trilogy
• Triple or Separate Biology
• Cells, Organization, Infection and Response, Bioenergetics

Cells

• All life consists of cells; visible with a light microscope
• Electron Microscopes: Higher resolution, can see organelles
• Magnification Formula: Magnification = Image size / Object size
• Cell Types:
  • Eukaryotic Cells: Have a nucleus (e.g., plant and animal cells)
  • Prokaryotic Cells: No nucleus
• Cell Structures:
  • Cell Membrane: Semi-permeable
  • Cell Wall (in plants/bacteria): Made of cellulose
  • Cytoplasm: Site for chemical reactions
  • Mitochondria: Respiration
  • Ribosomes: Protein synthesis
  • Chloroplasts (in plants): Photosynthesis
  • Vacuole (in plants): Stores sap

Triple Biology

• Bacteria: Multiply via binary fission
  • Practical: Culture bacteria using aseptic techniques

DNA and Mitosis

• DNA in Eukaryotic Cells: Found in chromosomes, humans have 23 pairs
• Mitosis: Cell duplication for growth and repair
  • Process: Genetic material duplicates, nucleus divides, two identical cells form
• Cell Specialization and Stem Cells
  • Examples: Nerve, muscle, plant cells
  • Stem Cells: Unspecialized; found in embryos and bone marrow
  • Applications: Combat conditions like diabetes and paralysis
  • Ethical Considerations: Cloning and stem cell use

Diffusion, Osmosis, and Active Transport

• Diffusion: Movement from high to low concentration (passive)
• Osmosis: Diffusion of water
• Active Transport: Movement against concentration gradient (requires energy)
  • Examples: Mineral uptake in roots

Organization

• Tissues: Groups of similar cells
• Organs: Groups of tissues (e.g., heart)
• Organ Systems: Groups of organs (e.g., digestive system)
• Digestive System: Breaks down food into nutrients
  • Stomach acid, enzymes, bile
  • Enzymes: Biological catalysts (amylase, protease, lipase)

Respiratory and Circulatory Systems

• Breathing vs. Respiration: Oxygen intake vs. energy production
• Gas Exchange: Occurs in alveoli
• Heart and Circulation:
  • Double circulatory system
  • Blood flows: Right side deoxygenated, left side oxygenated
• Blood Vessels
  • Arteries: Away from heart
  • Veins: Toward heart
  • Capillaries: Site of diffusion

Diseases

• Non-Communicable Diseases: E.g., cardiovascular disease, cancer
• Communicable Diseases: Caused by pathogens
  • Bacteria, viruses, fungi, protists
• Immune System: Protects from pathogens
  • White blood cells, lymphocytes, phagocytes
  • Vaccination: Introduces dead/inert pathogens for immunity

Bioenergetics

• Photosynthesis: Endothermic reaction in plants
  • Equation: Light energy, CO2 + H2O -> Glucose + O2
  • Factors: Light, temperature, CO2 concentration
• Respiration: Opposite of photosynthesis
  • Aerobic: With oxygen
  • Anaerobic: Without oxygen, produces lactic acid
• Metabolism: Sum of all cellular reactions

Practical Experiments

• Enzyme Activity: Affected by temperature and pH
• Osmosis: Potato cylinder experiment
• Photosynthesis: Pondweed oxygen production

These notes cover the main topics and practical experiments emphasized in the AQA GCSE Biology Paper 1 exam. For specific experiments and details, refer to lab manuals and the exam specification.