AQA GCSE Biology Paper 1 Lecture Notes

Overview

• Lecture by Lauren (expert examiner) covering AQA GCSE Biology Paper 1.
• Includes notes on animal and plant cell structures, cell differentiation, microscopes, culturing microorganisms, chromosomes, mitosis, stem cells, diffusion, osmosis, active transport, organizational hierarchy in living organisms, digestive system, blood and the heart, coronary heart disease, health and diseases, cancer, plant biology, photosynthesis, respiration, and metabolism.

Cell Structure

Animal Cells

• Cell Membrane: Controls entry/exit of substances.
• Cytoplasm: Site of chemical reactions.
• Ribosomes: Protein synthesis.
• Nucleus: Controls cell activities.
• Mitochondria: Site of aerobic respiration, energy provider.

Plant Cells

• Chloroplasts: Absorb light energy for photosynthesis.
• Permanent Vacuole: Supports cell structure.
• Cell Wall: Made of cellulose, provides structure.

Cell Comparison

• Differences: Cell wall, vacuole, chloroplasts (only in plant cells).
• Eukaryotic Cells: Have a nucleus, e.g., plant and animal cells.
• Prokaryotic Cells: No nucleus, e.g., bacterial cells.

Specialized Cells

• Plant Cells: Root hair cells, xylem, phloem.
• Animal Cells: Sperm, nerve, muscle cells.

Microscopes

• Light Microscopes: Used to view cell structures.
• Electron Microscopes: Higher resolution and magnification.

Culturing Microorganisms

• Bacteria divide by binary fission, grown in broth or agar.
• Aseptic Technique: Essential to prevent contamination.

DNA & Chromosomes

• DNA: Double helix, genes on chromosomes.
• Humans: 23 pairs of chromosomes.

Mitosis & Cell Cycle

• Interphase: Cell prepares by replicating DNA and growing.
• Mitosis: Division into two identical daughter cells.

Stem Cells

• Types: Embryonic, adult, plant (meristems).
• Therapeutic Cloning: Produces patient-identical embryonic stem cells.

Transport Mechanisms

Diffusion

• Net movement from high to low concentration, passive.

Osmosis

• Water movement through a semi-permeable membrane, passive.

Active Transport

• Movement against concentration gradient, requires energy.

Human Physiology

Digestive System

• Enzymes: Amylase, protease, lipase; break down carbohydrates, proteins, lipids.
• Bile: Produced by liver, neutralizes stomach acid, aids digestion.

Blood & Circulatory System

• Arteries: Transport blood away; high pressure.
• Veins: Transport blood to heart; low pressure.
• Capillaries: Exchange of substances.
• Heart: Double circulatory system.

Coronary Heart Disease

• Risk Factors: Diet, exercise, smoking.
• Treatments: Statins, stents, heart transplant.

Health & Diseases

• Communicable Diseases: Spread via pathogens.
• Non-communicable Diseases: Long-term, not spreadable.
• Cancer: Uncontrolled cell division.

Plant Biology

Photosynthesis

• Requires light energy, carbon dioxide, water.
• Produces glucose and oxygen.

Plant Transport Systems

• Xylem: Water/mineral ion transport.
• Phloem: Transport sugars from photosynthesis.

Respiration

• Aerobic: Uses oxygen, produces CO2 and water.
• Anaerobic: Without oxygen, produces lactic acid or ethanol.

Metabolism

• Sum of all chemical reactions in organisms.
• Involves synthesis and breakdown of molecules.

These notes cover the key concepts and details discussed in the lecture. They provide a comprehensive overview for students preparing for their exams in GCSE Biology Paper 1.