AQA GCSE Biology Paper 1 Overview

Topics Covered

• Cells
• Organization
• Infection and Response
• Bioenergetics

Cells

• Microscopy
  • Normal light microscopes can see cells and nucleus; electron microscopes show finer details.
  • Calculating cell size: Magnification = Image size / Object size.
• Types of Cells
  • Eukaryotic: Have a nucleus, e.g., plant and animal cells.
  • Prokaryotic: No nucleus.
  • Common structures: cell membrane, cytoplasm, mitochondria, ribosomes.
  • Plant cells: Additional features like cell wall, chloroplasts, and vacuole.
• Cell Division
  • Mitosis: Duplication process of cells for growth and repair.
• Specialized Cells and Stem Cells
  • Examples: nerve, muscle, root hair cells.
  • Stem cells: Undifferentiated and can specialize.
  • Ethical considerations of stem cell use.
• Diffusion and Osmosis
  • Movement from high to low concentration.
  • Osmosis: Specific to water.
  • Factors affecting rate: concentration gradient, temperature, surface area.
  • Practical examples with potatoes and sugar solutions.
• Active Transport
  • Energy-consuming process to move molecules against a concentration gradient.

Organization

• Cell Organization
  • Cells form tissues, tissues form organs, organs form organ systems.
• Digestive System
  • Breakdown of food into nutrients.
  • Enzymes: Biological catalysts for breaking down molecules.
• Enzymes
  • Specificity based on lock and key model.
  • Affected by temperature and pH.
  • Practical experiments involving amylase.

Respiratory System

• Breathing vs. Respiration
  • Breathing supplies oxygen for respiration.
• Heart and Circulatory System
  • Double circulatory system.
  • Blood flow through the heart.
  • Blood vessels: Arteries, veins, capillaries.
  • Heart health issues and treatments (e.g., stents, statins).
• Blood Components
  • Red and white blood cells, platelets, plasma.

Diseases and Defenses

• Non-Communicable Diseases
  • Examples: Cardiovascular disease, diabetes, cancer.
  • Risk factors: Diet, lifestyle, carcinogens.
• Communicable Diseases
  • Pathogens: Viruses, bacteria, fungi, protists.
  • Virus replication and diseases: Measles, HIV.
  • Bacterial diseases: Salmonella, gonorrhea.
  • Fungal and protist diseases.
• Body Defenses
  • Physical barriers (skin, mucus).
  • White blood cells: Lymphocytes and phagocytes.
  • Vaccines and immunity.

Bioenergetics

• Photosynthesis
  • Occurs in chloroplasts.
  • Equation: Light energy is needed.
  • Factors affecting rate: temperature, light intensity, CO2 concentration.
  • Practical example with pondweed.
• Respiration
  • Aerobic vs anaerobic respiration.
  • Anaerobic in muscles leads to lactic acid.
  • Fermentation in yeast produces ethanol.
  • Metabolism: Sum of all chemical reactions in cells.

Practical Experiments

• Focus on method and results interpretation.
• Common themes: Understanding of underlying biological processes and conditions affecting them.

Study effectively by understanding each concept and practicing with past paper questions to test your knowledge and application of concepts.