AQA GCSE Biology Paper 2 Overview

Homeostasis and Response

• Homeostasis: Regulation of internal conditions to maintain optimum function.
  • Controlled by negative feedback loops.
  • Key examples: Blood glucose concentration, body temperature, water levels.
• Pathways:
  • Receptors detect stimuli, coordination center decides response (brain, spinal cord, pancreas), effectors carry out response (muscle, gland).
• Systems:
  • Endocrine: Hormones in bloodstream, slow and long-lasting.
  • Nervous: Electrical impulses, rapid but short-lived.
• Nervous System Details:
  • Central Nervous System (CNS): Brain and spinal cord.
  • Reflex reactions: Fast, automatic responses not involving the brain.

Required Practical: Measuring Reaction Times

• Test reaction times using a ruler drop or computer program.
• Factors: Effects of caffeine, tiredness.

Brain and Eye

• Brain Structure:
  • Cerebrum, cerebellum, medulla, pituitary gland, hypothalamus.
• Eye Structure:
  • Sclera, cornea, pupil, iris, lens, retina.
  • Accommodation and response to light intensity.

Thermoregulatory System

• Temperature Control:
  • Vasodilation and vasoconstriction.
  • Sweating and shivering.

Endocrine System

• Glands: Pituitary, pancreas, thyroid, adrenal, ovaries/testes.
• Hormones: Thyroxine, adrenaline, insulin, glucagon.
• Diabetes:
  • Type 1: Genetic, treated with insulin injections.
  • Type 2: Lifestyle-related, treated with diet and exercise.

Water and Waste Control

• Osmoregulation: Balance of water and removal of waste.
• Kidney Functions:
  • Filtration, selective reabsorption, production of urine.
  • Kidney failure treatments: Dialysis, transplant.

Reproduction and Hormones

• Menstrual Cycle: FSH, LH, estrogen, progesterone.
• Contraceptive Methods: Hormonal and non-hormonal.
• Fertility Treatments: Use of hormones and IVF.

Plant Hormones

• Responses: Phototropism, geotropism.
• Hormones: Auxin, gibberellins, ethene.

Inheritance, Variation, and Evolution

• Reproduction Types: Sexual and asexual.
• Cell Division: Mitosis and meiosis.
• Genetics Basics: Genes, alleles, genotype, phenotype.
• Genetic Disorders: Cystic fibrosis, polydactyly.
• DNA Structure: Double helix, nucleotides, bases.

Genetic Engineering

• Process: Use of restriction enzymes, vectors.
• Applications: GM crops, insulin production.
• Cloning: Techniques for plants and animals.

Ecology

• Ecosystems: Biotic and abiotic factors, interdependence.
• Food Chains/Webs: Trophic levels, pyramids of biomass.
• Population Studies: Use of quadrats, transects.
• Biogeochemical Cycles: Water, carbon.

Human Impact on Environment

• Pollution: Water, air, land.
• Deforestation and Land Use: Effects on biodiversity.
• Global Warming: Greenhouse gases, consequences.

Food Security

• Challenges: Disease, environmental change, agricultural inputs.
• Solutions: Sustainable practices, biotechnology.

Biotechnology in Food Production

• Microprotein and Golden Rice: Nutrient enhancement.
• Genetic Engineering: Insulin production.