AQA GCSE Biology Paper 1 Review

Key Topics Covered

• Cells
• Organisation
• Infection and response
• Bioenergetics

Exam Types

• Suitable for higher and foundation tier
• Double combined trilogy
• Triple or separate biology

Cells

• Types of Cells
  • Eukaryotic Cells: Contain a nucleus (e.g. plant and animal cells)
  • Prokaryotic Cells: No nucleus, DNA in plasmids
• Microscopy
  • Light microscopes can view cells and nuclei
  • Electron microscopes provide higher resolution for organelles
  • Magnification calculation: Magnification = Image size / Object size
• Cell Structures
  • Cell membrane: Semi-permeable
  • Cell wall (plants): Made of cellulose
  • Cytoplasm: Site of chemical reactions
  • Mitochondria: Site of respiration
  • Ribosomes: Protein synthesis
  • Chloroplasts (plants): Site of photosynthesis
  • Vacuole (plants): Stores sap

Cell Division and Specialization

• Mitosis: Cell division for growth and repair
• Stem Cells: Unspecialized cells found in embryos and bone marrow
• Cloning:
  • Ethical considerations
  • Cloning plants to preserve species or enhance traits

Transport Mechanisms

• Diffusion: Movement of molecules from high to low concentration
• Osmosis: Diffusion of water across a membrane
• Active Transport: Movement of substances against a concentration gradient using energy

Organisation

• Tissues, Organs, and Systems
  • Tissues: Groups of similar cells
  • Organs: Groups of tissues
  • Organ systems: Groups of organs
• Digestive System
  • Breakdown of food by acids and enzymes
  • Bile neutralizes stomach acid and emulsifies fats
• Enzymes
  • Biological catalysts
  • Specific substrates fit into active sites (lock and key model)
  • Affected by temperature and pH

Heart and Circulatory System

• Heart Structure and Function
  • Double circulatory system
  • Deoxygenated blood enters right side, oxygenated exits left
• Blood Vessels
  • Arteries: Carry oxygenated blood (except pulmonary artery)
  • Veins: Carry deoxygenated blood (except pulmonary vein)
  • Capillaries: Site of gas exchange

Plant Transport

• Xylem and Phloem
  • Xylem: Water transport, unidirectional, transpiration
  • Phloem: Sugar transport, bidirectional, translocation

Infection and Response

• Pathogens: Viruses, bacteria, fungi, protists
• Immune System
  • Skin, mucus, and enzymes as barriers
  • White blood cells produce antibodies and antitoxins
  • Vaccines introduce inert pathogens to build immunity

Diseases

• Non-communicable: Lifestyle-related, genetic
• Communicable: Pathogen-induced, e.g., measles, HIV
• Cancer: Benign vs malignant tumors

Bioenergetics

• Photosynthesis
  • Takes place in chloroplasts
  • Equation: Carbon dioxide + Water + Light energy -> Glucose + Oxygen
  • Factors affecting rate: Light, temperature, CO2 concentration
• Respiration
  • Aerobic: With oxygen, produces more energy
  • Anaerobic: Without oxygen, produces lactic acid or ethanol
• Metabolism
  • Sum of all chemical reactions
  • Includes conversion of glucose, synthesis of proteins and lipids

Practical Experiments

• Osmosis with Potatoes
• Enzyme Activity with Amylase
• Photosynthesis with Pond Weed

These notes cover the essential information and concepts needed for AQA GCSE Biology Paper 1. They serve as a comprehensive guide to review before the exam.