Edexcel GCSE Biology Paper 1 Overview

Topics Covered

• Key Concepts
• Cells and Control
• Genetics
• Natural Selection and Genetic Modification
• Health, Disease, and Medicines

These topics are applicable for the Higher and Foundation Tier double combined or triple separate course. Additional concepts may be included for the triple course.

Cells and Microscopy

• Microscopes:
  • Light microscopes: Used to see cells and nuclei.
  • Electron microscopes: Allow for seeing finer details like organelles due to higher resolution.
• Cell Types:
  • Eukaryotic: Have a nucleus (e.g., plant and animal cells).
  • Prokaryotic: No nucleus, DNA in plasmid form.

Cell Structure

• Cell Membrane: Semi-permeable, controls substance entry.
• Cell Wall (Plants/Bacteria): Provides structure, made of cellulose.
• Cytoplasm: Site of chemical reactions.
• Mitochondria: Site of respiration.
• Ribosomes: Protein synthesis.
• Chloroplasts (Plants): Site of photosynthesis.
• Vacuole (Plants): Stores sap.

Enzymes

• Function: Biological catalysts that are specific to certain reactions.
• Lock and Key Model: Enzymes and substrates fit specifically.
• Factors Affecting Activity:
  • Temperature and pH can denature enzymes.
  • Optimum temperature/pH maximizes activity.

Diffusion and Osmosis

• Diffusion: Movement from high to low concentration, passive process.
• Osmosis: Diffusion of water across a semi-permeable membrane.
• Active Transport: Uses energy to move substances against a gradient.

Genetics

• DNA Structure: Double helix polymer made of nucleotides.
• Mitosis: Cell division for growth and repair, results in two identical cells.
• Meiosis: Produces gametes for sexual reproduction, results in genetic variation.
• Genetic Terms:
  • Genotype: Genetic constitution.
  • Phenotype: Physical expression.
  • Alleles: Different forms of a gene, dominant or recessive.

Nervous System

• Components: CNS (brain and spinal cord) and PNS (peripheral nerves).
• Reflex Arc: Fast response by bypassing the brain.

The Eye

• Accommodation: Ability to focus on near and far objects by changing lens shape.
• Vision Issues:
  • Myopia: Short-sightedness.
  • Hyperopia: Long-sightedness.

Natural Selection and Evolution

• Darwin's Theory: Survival of better adapted individuals.
• Selective Breeding: Enhancing desired traits in organisms.
• Genetic Engineering: Modifying organisms' DNA for desired traits.

Health and Disease

• Non-Communicable Diseases: Result from lifestyle choices and genetics (e.g., cardiovascular disease).
• Communicable Diseases: Caused by pathogens (e.g., viruses, bacteria, fungi).
• Immune System: Defends against pathogens through antibodies and vaccinations.

Biotechnology and Medicine

• Antibiotics: Treat bacterial infections but not viruses.
• Vaccines: Use inactive pathogens to stimulate immunity.
• Monoclonal Antibodies: Used for diagnosis and treatment despite potential side effects.

This overview provides a summary of the key concepts and information covered in the Edexcel GCSE Biology Paper 1.