Define health

Why is health difficult to define?

Define disease

What are the issues with defining disease?

What is a difficulty in defining health and disease in terms of the way the words are used in different contexts?

What is the function of genes in the maintenance of health?

What is the function of mitosis in the maintenance of health?

What are the two types of genes which control mitosis?

In terms of proto-oncogenes and tumour suppressors, for a healthy organism, what should be the ratio of these genes present? What are the implications of damage to these genes?

Define cell differentiation and cell specialisation.

What type of organisms need specialised cells, for what purposes? Provide examples of specialised cells.

> Syllabus dot point: Use available evidence to analyse the links between gene expression and maintenance and repair of body tissues

What do enzymes control?

True or false: Enzymes are a type of protein

What are proteins (specifically enzymes) made up of?

What is responsible for the production of polypeptides?

Therefore if enzymes control cellular metabolism, and enzymes are proteins made of polypeptides. Genes produce these polypeptides. Now, what would happen if the information in a gene is damaged or not expressed?

Again, to refresh your memory: What are the two types of genes which control mitosis (cell division, growth and repair)?

What do proto-oncogenes do (in some detail)?

What are mutated proto-oncogenes called?

What do tumour suppressor genes do? (in some detail?

What happens if tumour suppressor genes are mutated?

True or false: A mutation in the proto-oncogene can cause cancer.

Provide an example of a cancer due to mutation:

What happens without DNA repair genes, or if they are damaged? When can DNA repair genes be damaged?

Suggest some requirements then, for a healthy body in terms of genes and cell division: