AQA GCSE Biology Paper 1 Overview

Key Concepts

• Suitable for: Higher and Foundation tiers, double combined trilogy, and triple or separate biology.
• Main Topics: Cells, organization, infection and response, bioenergetics.

Cells

• Microscopes:
  • Light microscopes allow visibility of cells and nucleus.
  • Electron microscopes offer greater detail, resolving power, and higher resolution.
• Cell Types:
  • Eukaryotic Cells: Have a nucleus, e.g., plant and animal cells.
  • Prokaryotic Cells: No nucleus.
• Cell Structures:
  • Cell membrane: Semi-permeable, regulates entry and exit.
  • Cell wall: Found in plants, bacteria; made of cellulose.
  • Cytoplasm: Site of chemical reactions.
  • Mitochondria: Respiration occurs, releases energy.
  • Ribosomes: Protein synthesis.
  • Chloroplasts: Photosynthesis in plant cells.
  • Vacuole: Stores sap in plant cells.

Advanced Topics (Triple)

• Bacterial Multiplication: Binary fission.
• Aseptic Techniques: Used in culturing bacteria.

Cell Specialization and Division

• Chromosomes: Eukaryotic cells have DNA in chromosomes; humans have 23 pairs (diploid cells).
• Mitosis: Process of cell division for growth and repair.
• Stem Cells:
  • Found in embryos, marrow, plant meristems.
  • Potential in treating diseases like diabetes and paralysis.

Transport Mechanisms

• Diffusion: Movement from high to low concentration; passive process.
• Osmosis: Diffusion of water across membranes.
• Active Transport: Requires energy, moves substances against concentration gradient.

Organization

• Cells form tissues, tissues form organs, organs form systems.
• Digestive System: Breaks down food into nutrients using enzymes.

Enzymes

• Function: Biological catalysts, specific to substrates (lock and key model).
• Activity: Influenced by temperature and pH.
• Practical: Amylase activity with starch.

Respiratory System

• Involves gas exchange; oxygen transported by hemoglobin.

Circulatory System

• Heart: Double circulatory system; pumps deoxygenated blood to lungs and oxygenated blood to body.
• Blood Vessels: Arteries, veins, capillaries.
• Heart Health: Impacted by diet, lifestyle; treatments include stents, statins.

Disease and Immunity

• Non-communicable Diseases: Include CHD, diabetes, cancer.
• Communicable Diseases: Caused by pathogens; viruses, bacteria, fungi, protests.
• Immune System: White blood cells combat pathogens.
• Vaccinations: Expose immune system to pathogen antigens.
• Antibiotics: Target bacteria, not viruses; resistance is an issue.

Photosynthesis

• Happens in chlorophyll; endothermic process.
• Factors Affecting Rate: Light, temperature, CO2.
• Practical: Measuring oxygen production in pondweed.

Respiration

• Aerobic: Requires oxygen, produces energy.
• Anaerobic: Produces lactic acid or ethanol, less energy.

Metabolism

• Sum of all chemical reactions in an organism.
• Includes synthesis of biomolecules and breakdown processes.

Additional Triple Content

• Monoclonal Antibodies: Used for disease treatment, diagnosis.

This guide is intended to provide a comprehensive overview of the key concepts necessary for AQA GCSE Biology Paper 1. Be sure to review these topics in detail and practice related experiments where possible.