GENETIC MUTATIONS
Open and read the document “Genes are made of DNA”.
Answer the following questions.
Once completed, print it out and stick it in your book for future reference.
1. Define ‘mutation’.
2. Explain what a mutagen is. Give some examples of mutagens and how they act to cause mutations.
3. Compare a gene mutation and chromosome mutation.
4. Explain why mutations can result in a change in protein function.
5. Complete the following table:
Type of mutation
Point mutation
Frameshift mutation
Explanation
Example
Read the article “Disadvantages of mutations”, then complete the following:
1. Complete the summary using words from the wordlist:
caused
mutations
defects
treat
occur
invade
cell
increases
function
fertility
cancer
lifetime
ability
chemicals
daughter
age
low
Changes in a cell’s DNA are called ____________. Most mutations don’t harm the __________ but
some cause significant problems by interfering with the cell’s ability to ______________ normally.
Mutations normally occur throughout an organism’s ___________. They are passed on to
_____________ cells when cell division takes place. As an organism gets older, the number of
cells with mutations ____________ and its cells don’t function as well.
Cancer is _________ by mutations. A tumour is a mass of mutated cells that have lost the
____________ to function. Sometimes cells break away from the tumour, to __________ other
parts of the body and grow into secondary tumours. Once cancer reaches this stage it can be
difficult to __________.
Mutations in eggs and sperm can cause birth ____________ and miscarriages. The risk of these
cells containing mutations increases with ___________ and can cause __________ problems in
couples who wait too long before having children. Mutations occur at a ______________ rate
throughout life but some __________ and some forms of radiation increase the rate at which
mutations ______________. This is why smoking and sunbaking can cause ____________.
2. The risk of getting cancer increases as you get older. Suggest a reason why.
3. Explain why older couples have more fertility problems than younger couples.
4. X-rays cause mutations. If you need an X-ray, the radiologist taking it:
a. will stand behind a protective screen. Why?
b. may place a protective covering over your lap if there is a danger of X-rays reaching your
ovaries or testes. Why?