WJEC A Level Biology
WJEC A Level Biology 3.7 Homeostasis and the Kidney Exam Questions
Free WJEC A Level Biology exam questions on 3.7 Homeostasis and the Kidney, with mark schemes. Covers negative feedback, kidney structure, ultrafiltration, selective reabsorption, ADH and osmoregulation.
3.7 Homeostasis and the Kidney exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
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WJEC A Level Biology Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About WJEC A Level Biology 3.7 Homeostasis and the Kidney
This topic explains how the kidney controls blood composition. Expect nephron diagrams and ADH questions.
What you need to know
- Homeostasis Maintaining internal conditions using negative feedback.
- Nephron Glomerulus and Bowman's capsule for ultrafiltration; proximal convoluted tubule for selective reabsorption; loop of Henle creates a gradient.
- ADH Released by the posterior pituitary when water potential is low; makes collecting duct walls more permeable to water.
- Kidney failure Dialysis and transplants, and adaptations of desert animals.
Common mistakes in 3.7 Homeostasis and the Kidney
- Saying ADH makes urine more dilute.
- Forgetting glucose is fully reabsorbed in the proximal tubule.
- Confusing ultrafiltration with reabsorption.
Try three 3.7 Homeostasis and the Kidney exam-style questions
1. Explain how ultrafiltration occurs. (2 marks)
Show the mark scheme answer
High hydrostatic pressure in the glomerulus (1) forces small molecules through the basement membrane into the Bowman's capsule (1).
2. Explain the effect of ADH on urine. (3 marks)
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ADH increases permeability of the collecting duct (1) so more water is reabsorbed (1), producing a smaller volume of concentrated urine (1).
3. Explain why desert animals have long loops of Henle. (2 marks)
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A longer loop creates a steeper sodium ion gradient in the medulla (1), so more water can be reabsorbed (1).
3.7 Homeostasis and the Kidney FAQs
What does Homeostasis and the Kidney cover?
Negative feedback, the nephron, osmoregulation and kidney failure.
Which practical links here?
Dissection of a kidney or examining kidney tissue.
Where is ADH released?
From the posterior pituitary gland.
Revise this topic with flashcards: WJEC A Level Biology Flashcards, with mark scheme answers for Anki and Quizlet.
