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Questions involving processes in respiration and photosynthesis usually give high marks in the Biology A level AQA unit 4 papers. By understanding and learning key parts of the processes, you can ensure y...

To start with, let’s just quickly define an enzyme. An enzyme is a biological molecule that is able to speed up a reaction. Without the presence of enzymes, certain reactions just wouldn’t be able to take...

There are four key points to natural selection:

• first, that individuals in all species show variation
• second, that this variation is genetic and therefore heritable
• third, t...

Neurotransmission is a mechanism of propagating an electrical signal between neurons via the movement of charged particles. It is initiated when the arrival of an action potential at the axon terminal tri...

The mutation alters the base sequence which therefore changes the sequence of Amino Acids coded for (the primary structure). Now the sequence of Amino Acids has been changed when bonds form and folding oc...