Edexcel GCSE Biology Topic 7: Animal Coordination, Control and Homeostasis Exam Questions

About Edexcel GCSE Biology Topic 7: Animal Coordination, Control and Homeostasis

Topic 7 of Edexcel GCSE Biology is assessed on Paper 2. It covers the endocrine system and how hormones such as adrenaline and thyroxine act, the hormonal control of the menstrual cycle, contraception and assisted reproductive technology, and homeostasis including blood glucose control and diabetes. GCSE Biology students also study thermoregulation and osmoregulation, including the structure and function of the kidney and ADH. Examiners commonly test hormone graphs for the menstrual cycle, negative feedback (Higher tier), differences between type 1 and type 2 diabetes, and the stages of urine formation in the nephron.

What you need to know

• Hormones and glands Hormones are chemical messengers carried in the blood to target organs. Know the pituitary, thyroid, pancreas, adrenal glands, ovaries and testes. Adrenaline prepares the body for fight or flight by increasing heart rate, blood pressure and blood flow to muscles and raising blood glucose.
• Thyroxine (Higher tier only) Thyroxine regulates metabolic rate. Its level is controlled by negative feedback involving TRH from the hypothalamus and TSH from the pituitary gland.
• Menstrual cycle Oestrogen and progesterone control the cycle: oestrogen builds the uterus lining and progesterone maintains it. Higher tier: FSH stimulates follicle development, LH triggers ovulation, and the hormones interact through feedback.
• Contraception and ART Hormonal contraception (pill, implant, injection) prevents ovulation or thickens cervical mucus; barrier methods such as condoms prevent sperm reaching the egg and condoms also reduce STI spread. Higher tier: clomifene therapy stimulates ovulation and IVF fertilises eggs outside the body.
• Thermoregulation (Biology only) The hypothalamus detects blood temperature. If too hot: sweating and vasodilation. If too cold: shivering, vasoconstriction and reduced sweating.
• Blood glucose and diabetes Insulin from the pancreas causes body cells to take up glucose and the liver and muscles to store it as glycogen. Higher tier: glucagon converts glycogen back to glucose. Type 1 diabetes is treated with insulin; type 2 is treated with diet, exercise and medication and is linked to obesity, measured by BMI or waist to hip ratio.
• Osmoregulation and the kidney (Biology only) The nephron filters blood under pressure (ultrafiltration), selectively reabsorbs glucose in the proximal tubule and reabsorbs water in the collecting duct under the control of ADH. Urea is made in the liver from excess amino acids. Kidney failure is treated by dialysis or transplant.

Common mistakes in Topic 7: Animal Coordination, Control and Homeostasis

• Confusing glucagon and glycogen. Glucagon is a hormone; glycogen is the stored carbohydrate.
• Saying adrenaline is controlled by negative feedback in the same way as thyroxine. Adrenaline is released in response to fear or stress and acts quickly.
• Saying blood vessels move towards the skin when hot. Arterioles supplying skin capillaries dilate, increasing blood flow near the surface.
• Saying ADH makes more urine. ADH increases the permeability of the collecting duct, so more water is reabsorbed and less, more concentrated urine is produced.
• Saying people with type 2 diabetes produce no insulin. Their cells do not respond properly to insulin.

Try three Topic 7: Animal Coordination, Control and Homeostasis exam-style questions