Inq. 4

Question 1

Define mutagens

Answer 1

• environmental agents alter DNA and cause mutations
• the process of inducing a mutation is called mutagenesis
• carcinogens are cancer-causing mutagens

Question 2

Chemical mutagens

Answer 2

• chemicals that cause mutations are usually structurally similar to normal bases in DNA and so they become incorporated by mistake during replication
• their insertion results in a change in the DNA and therefore the mRNA so a non-functional protein can result.
• Chemicals can insert themselves in between bases and cause a frame shift.

Question 3

Naturally-occurring mutagens

Answer 3

• agents that are present in the environment at normal levels and may cause mutations
• can be biological or non-biological

Question 4

example of naturally-occurring mutagens

Answer 4

human papillomavirus (HPV) can cause cervical cancer

Question 5

Biological/non-biological mutagens

Answer 5

Biological:
- end products of metabolism
- transposons (sections in DNA that relocate themselves)
- microbes
Non-biological:
- naturally occurring substances (mercury, cadmium, etc.)

Question 6

Physical mutagens

Answer 6

• substances including heat and ionising radiation
• they can physically interact with the DNA molecule

Question 7

Example of physical mutagens

Answer 7

Electromagnetic radiation (ultraviolet, etc.)

Question 8

What are the criteria that distinguish mutations?

Answer 8

1. Origin (cause) of mutation
2. Amount of material changed
3. Effect of mutation on genotype
4. Effect of mutation on phenotype
5. Heritability