5.1.6-7

Question 1

What are the male and female parental genotypes?

Answer 1

M - XY

F - XX

Question 2

Define mutation.

Answer 2

Alteration in DNA base sequence.

Question 3

What do mutations lead to?

Answer 3

Variation

Question 4

What are the possible outcomes when a mutation occurs? (In terms of phenotypes)

Answer 4

Position of mutation in DNA sequence affects the outcome:

1) No effect
2) Influence phenotype
3) Very few determine phenotypes

Question 5

Give examples of harmful mutations.

Answer 5

Ionising radiation can occur causing cancer (uncontrollable division of cells)

These produce abnormal protein channels that can’t function properly - cystic fibrosis

Cause different shaped proteins to be made - e.g. sickle cell anaemia.

Question 6

Give examples of neutral mutations.

Answer 6

Ear lobe shape, rolling tongue

Question 7

Give examples of beneficial mutations.

Answer 7

Antibiotic resistant bacteria.

Question 8

How can proteins be incorrectly produced/folded?

Answer 8

DNA bases are changed, the order of bases may be changed so that different amino acids and produced and in turn different proteins that are a different shape.

Question 9

How can incorrect protein formation affect enzymes?

Answer 9

If the protein is an enzyme, the incorrect active site shape means it can no longer bind to its former substrate leading to potential metabolic diseases, such as PKU. This results in the amino acid, phenalalynine not being broken down by the body leading to brain damage.

Question 10

What effect can mutations have of non-coding DNA?

Answer 10

Non-coding DNA (bases that don’t code for proteins), trigger transcription and translation, so the protein may not be coded for at all.