Q24 (c)

Criteria	Marks
Identifies a type of chromosomal mutation; explains the cause of the mutation	3
Outlines the cause of a chromosomal mutation	2
Provides some relevant information about a chromosomal mutation	1

Sample answer:

One type of chromosomal mutation is a numerical abnormality. This is where there are more or fewer chromosomes than the normal diploid cell. These abnormalities can be caused during meiosis due to non-disjunction. Non-disjunction means that a pair of homologous chromosomes fails to separate/segregate during meiosis so that some of the gametes have one chromosome too many and some of the gametes have one chromosome too few.

Answers could include:

Chromosomal alterations such as deletions, duplications, inversions or translocations.