AQA GCSE Biology Paper 1 Overview

General Information

• Covers higher & foundation tier, double combined trilogy, and triple/separate biology.
• Topics: Cells, organization, infection & response, bioenergetics.
• Distinctions made for triple content, but not higher tier as differences are minimal.

Cells

Basics

• All life consists of cells; visible under a microscope.
• Types: Ukaryotic (with nucleus) and Prokaryotic (without nucleus).
  • Ukaryotic: Plant & animal cells.
  • Prokaryotic: Bacteria.

Cell Structures

• Cell Membrane: Semi-permeable.
• Cell Wall: Plant cells & most bacteria, made of cellulose.
• Cytoplasm: Site of chemical reactions.
• Mitochondria: Respiration and energy release.
• Ribosomes: Protein synthesis.
• Chloroplasts (Plants): Photosynthesis.
• Vacuole (Plants): Stores sap.

Cell Division

• Mitosis: Duplicates cells for growth/repair.
  • Process: Genetic material duplicated, nucleus divides.
• Stem Cells: Unspecialized; potential for medical use.
• Diffusion & Osmosis: Movement of molecules, affected by concentration, temperature, and surface area.

Organization

Hierarchy

• Cells form tissues, tissues form organs, organs form systems.
• Digestive System: Breaks down food, involving enzymes and bile produced by the liver.

Enzymes

• Specificity: Works on lock-and-key principle.
• Activity factors: Temperature and pH.
• Practical: Testing enzyme activity with iodine and a starch solution.

Infection and Response

Pathogens

• Types: Viruses, bacteria, fungi, protists.
• Viruses: Cannot reproduce on their own; HIV example.
• Bacteria: Release toxins.
• Fungi and Protists: Cause diseases like athlete's foot and malaria.

Body Defenses

• Skin, mucus, stomach acid; white blood cells attack pathogens.
  • Lymphocytes: Produce antibodies.
  • Phagocytes: Ingest pathogens.
• Vaccination: Dead/inert pathogen exposure to stimulate immune response.

Antibiotics

• Kill bacteria, not viruses.
• Overuse leads to resistance.

Bioenergetics

Photosynthesis

• Occurs in chloroplasts; provides food for plants.
• Factors: Light, temperature, CO2 levels.
• Practical: Measuring oxygen production with pondweed.

Respiration

• Aerobic: With oxygen, more energy efficient.
• Anaerobic: Without oxygen, less energy, produces lactic acid.
• Fermentation: Used in baking, brewing.

Metabolism

• Sum of all chemical reactions in organisms.
• Includes: Respiration, protein synthesis, conversion processes.

Summary

• Comprehensive review of critical concepts needed for the exam.
• Emphasis on practical applications and experiments.

These notes encapsulate the essential points covered in the lecture, providing a structured overview of key concepts for AQA GCSE Biology Paper 1.