AQA · Biology · 8461
GCSE Biology: Maintaining water and nitrogen balance in the body
Homeostasis and response · AQA GCSE Biology (8461), specification point 4.5.3.3. Cards are generated from the exam board's own specification for "Maintaining water and nitrogen balance in the body", and every card links back to the page it came from. Separate science only. Specification © AQA — used with attribution.
12 flashcards · Free to study · No account needed
Study this deck
Preparing your cards…
All questions and answers
Read through the full deck, or practise recalling each answer above.
Which three substances are lost from the skin in sweat?
Show answer
Water, ions and urea.
Can the body control water loss via the lungs and skin?
Show answer
No — there is no control over water, ion or urea loss by the lungs or skin. Only the kidneys regulate it.
Which organ removes excess water, ions and urea from the body?
Show answer
The kidneys, which remove them in the urine.
What happens to body cells that lose or gain too much water by osmosis?
Show answer
They do not function efficiently.
In the liver, excess amino acids are ? to form ammonia.
Show answer
deaminated
Why is ammonia in the liver immediately converted to urea?
Show answer
Ammonia is toxic; urea can be excreted safely.
Which two processes do the kidneys use to produce urine?
Show answer
Filtration of the blood, then selective reabsorption of useful substances (glucose, some ions and water).
Which gland releases the hormone ADH?
Show answer
The pituitary gland.
Under what condition is ADH released into the blood?
Show answer
When the blood is too concentrated (water level too low).
What effect does ADH have on the kidney tubules?
Show answer
It increases their permeability to water, so more water is reabsorbed back into the blood.
What type of control mechanism regulates water level via ADH?
Show answer
Negative feedback.
Name the two treatments for kidney failure.
Show answer
Kidney transplant or kidney dialysis.
Want to create your own cards? Create a free account. AI generation uses credits.