Mutations

Question 1

what is a mutation?

Answer 1

a change in the sequence of DNA

Question 2

what causes mutations?

Answer 2

• this can be due to the replacement of a single base pair with a different pair, or an addition or deletion of one or more base pairs
• this gives a change in the DNA sequence which in turn changes the sequence of amino acids in the protein - this will normally alter the shape and function of the protein

Question 3

what is a chromosomal mutation?

Answer 3

when a cell gains an extra chromosome or one part of a chromosome is stuck onto another chromosome

Question 4

why are mutations rare in eukaryotes?

Answer 4

because our cells can detect and correct many mistakes in the DNA sequence

Question 5

are chromosomal mutations harmful?

Answer 5

they are almost always harmful, as they result in over or underproduction of proteins

Question 6

what type of changes to the DNA sequence are there?

Answer 6

neutral, positive (increase variation and may be beneficial if the environmental changes) or negative (the protein fails to work properly)

Question 7

what happens if mutation occurs during meiosis in a gamete?

Answer 7

it will affect all of the cells in the individual that develops from the gamete - this means that the mutation is inherited

Question 8

what happens if mutation occurs in a body cell?

Answer 8

it will affect only those cells produced by mitosis from the affected cell - mutations in the body cell give rise to caners of the cells that are affected - this type of mutation is not inherited

Question 9

what are mutagens?

Answer 9

chemicals which cause more frequent mutations - they include:
- ionising radiations
- some chemicals

Question 10

do mutations increase or decrease genetic variation in a population?

Answer 10

increase