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Biology GCSE like any other requires a basic level of understanding, but in addition it requires you to use scientific terminology. By using specific words or descriptions in your answers you make it easi...

They can engulf and ingest pathogens; this is essentially the white blood 'eats' the pathogen. They secrete (release) antitoxins which counteract the toxins released by pathogens. The toxins they release ...

Another proposed model is induced fit. This suggests that the substrate and active site are not a perfect match to each other. So inorder to fit together both the substrate and active site must change sha...

The lock and key model:

Only substrates of a specific shape that is complementary to the active site of an enzyme can fit into the active site, in a way that is analagous to a key fitting...

Very thin walls result in a short diffusion distance which makes gas exchange particularly favourable.

Lots of branches and sacs result in a large surface area so gas exchange can be maxi...