Edexcel GCSE Biology Paper 2 Overview

Topics Covered

• Topic 6: Plants
• Topic 7: Coordination and Control & Homeostasis
• Topic 8: Exchange and Transport
• Topic 9: Ecosystems

Topic 6: Plants

Plant Organs and Functions

• Leaves: Photosynthesis and transpiration.
• Roots: Water and mineral ion absorption; site of new cell production.
• Xylem: Transports water unidirectionally.
• Phloem: Transports sugars bidirectionally (translocation).

Factors Affecting Transpiration

• Increased by high temperatures, low humidity, and high air movement.

Leaf Structure

• Waxy Cuticle: Waterproof to prevent evaporation.
• Upper Epidermis: Transparent for light passage.
• Palisade Mesophyll: Photosynthesis center with chloroplasts.
• Spongy Mesophyll: Facilitates gas exchange.
• Lower Epidermis: Contains stomata for gas exchange.

Photosynthesis

• Equation: 6CO2 + 6H2O + light → C6H12O6 + 6O2
• Factors Affecting Rate: Temperature, light intensity, CO2 concentration.

Plant Hormones

• Gibberellins: Seed germination, flowering.
• Ethene: Fruit ripening.
• Auxins: Growth direction (phototropism and geotropism).

Topic 7: Coordination, Control, and Homeostasis

Homeostasis

• Maintains internal conditions (e.g., temperature, water balance).

Thermoregulation

• Sweating and Vasodilation: Cools the body.
• Shivering and Vasoconstriction: Warms the body.

Endocrine System

• Pituitary Gland: Master gland; regulates others.
• Pancreas: Insulin and glucagon production.
• Adrenal Glands: Produce adrenaline.

Blood Glucose Regulation

• Insulin: Lowers blood glucose.
• Glucagon: Raises blood glucose.

Diabetes

• Type 1: Lack of insulin production.
• Type 2: Cells resist insulin.

Kidneys and Water Balance

• ADH: Regulates water reabsorption in kidneys.
• Dialysis: Mimics kidney function.

Menstruation and Reproduction

• Hormonal control of egg maturation and release.
• Contraception Methods: Pills, barriers, surgical methods.
• IVF: Fertility treatment.

Topic 8: Exchange and Transport

Circulatory System

• Heart Structure: Double circulatory system; pathways of blood flow.
• Blood Vessels: Arteries, veins, capillaries.

Respiratory System

• Components: Trachea, bronchi, alveoli.
• Gas Exchange: Oxygen diffuses into blood; carbon dioxide out.

Respiration

• Aerobic: Glucose + oxygen → carbon dioxide + water + energy
• Anaerobic: Glucose → lactic acid + energy

Topic 9: Ecosystems

Ecosystem Dynamics

• Abiotic and Biotic Factors: Affect population distribution.
• Food Chains: Energy flow through trophic levels.
• Carbon and Water Cycles: Natural recycling processes.

Human Impact and Conservation

• Biodiversity: Importance and threats.
• Food Security: Challenges and solutions.

Environmental Issues

• Deforestation and Peat Bogs: Impact on ecosystems.
• Climate Change: CO2 and methane contributions.

Sustainable Practices

• Fishing and Farming: Methods to ensure resource availability.

These notes cover the key points and concepts discussed in the Edexcel GCSE Biology Paper 2 lecture. Use these as a guide for further study and review of each topic.