Practice Questions

1.What is meant by a mutation?

A mutation is a change in the sequence of bases in DNA.

2.Explain why many mutations have no effect on an organism.

Many mutations have no effect on an organism because:

They do not change the amino acid sequence (due to the genetic code being redundant), so the same protein is made.
They only cause a small change in the protein, which does not affect its shape or function.

3. Explain why mutations in non-coding regions can be important even though they do not code for proteins.

Mutations in non-coding regions can still be important because these regions often control gene expression.

Non-coding DNA can act as switches that turn genes on or off.
A mutation in these regions may cause a gene to be turned on at the wrong time, in the wrong place, or not at all.
This changes the amount or timing of protein produced, which can affect the organism’s characteristics.

So, even though they do not code for proteins, they can still have a significant effect on how genes are used.