IGCSE Biology Revision Notes


IGCSE Biology-Revision notes/Study notes0610 Biology Highly popular notes-with solved exam question examples designed by Cambridge expert teachers  with regular updates.

This section on biology revision notes  will be developed in a unique way. Not like the way it is normally done. Here We plan to pick random topics that we feel are  tougher  or challenging and then make them easier as much as possible.


Topic13:  excretion:

13.1-Excretion basics

13.2-Assimilation and deamination

13.3-Functions of liver


13.6-Kidney transplant-advantages-disadvantages

13.7-Structure of kidneys-Ultrafiltration


 Now here are a few questions taken from past papers[ answers provided below] to check your understanding of the above concepts that you studied from the past papers:

  1. Define excretion [3]
  2. How is urea transported in the blood to the kidney?[1]
  3. What happens to the amono acids in the liver cells?[3]
  4. Label the parts of the kidney tubule from A to D and  state one function of each[8]glomerulus labelled diagram



  1. Excretion is the removal of the waste products of metabolism and toxic   and harmful products and also products in excess of their  requirements.
  2. Urea gets dissolved in the blood and is then transported to the kidneys 
  3. The proteins are synthesised in the liver.Excess of the amino acids are broken down [ deaminated]. During deamination, amino group is removed from ammonia and is changed to urea.Rest of the molecule is respired to provide energy. The amine group can also be transferred via transamination to make new amino acids.
  4. The parts and their fuctions are as follows:
  • A-Glomerulus- Function: Filtration of blood
  • B-capsule-Function: To collect the filtrate
  • C-Tubule- Selective reabsorption of water/salts/minerals/ions
  • D-Collecting duct-reabsorbs water or passes urine to pelvis or ureter

More questions and topics comming up soon. Stay tuned.


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