1. a) How are second messengers generated from phosphatidylinositol (Pl)?
b) What are the main function(s) of the second messengers derived from Pl?

2. a) In the context of tumourigenesis, what is a gain-of-funtion mutation?
b) List two effects that gain-of-function mutations may have on encoded protein.
c) Briefly describe two different mechanisms that may lead to gain of function mutations in tumour cells, and give one ex of each.

3. a) describe what is meant by the term 'extracellular matrix' and five two ex of proteins that may be found in the extracellular matrix.
b) Name and describe the processes by which tumour cells:
i. move from their site of origin
ii. spread within the body
c) Give two exs of how changes in protein expression by the tumour cells can affect their ability to spread within the body.

4. a) What are free radicals? Give one ex of a free radical and briefly outline the process by which it is produced.
b) What particular characteristics of mitochondrial DNA make it more susceptible to damage than nuclear DNA? Give three reasons.
c) Give two exs of molecules that protect cells against reactive oxygen species and describe how tey do so.