Q6: Mutations

Question 1

Mutation

Answer 1

Any change to the quantity or the base sequence of the DNA of an organism.

Question 2

Gene mutation

Answer 2

Any change to one or more of the nucleotide bases, or a change in the sequence of the bases in DNA.

Question 3

Chromosome mutations

Answer 3

Changes in the structure or number of whole chromosomes.

Question 4

Two types of chromosome mutations

Answer 4

• changes in whole sets of chromosomes

- changes in the number of individual chromosomes

Question 5

Changes in whole sets of chromosomes

Answer 5

Occur when organisms have three or more sets of chromosomes rather than the usual two, eg: polyploidy in plants

Question 6

Changes in the number of individual chromosomes

Answer 6

Non-disjunction occurs and results in a gamete having one more or one less chromosome. Then during fertilisation with a normal gamete, the resultant offspring have more or fewer chromosomes than normal in all their body cells.

Question 7

Non-disjunction

Answer 7

Individual homologous pairs of chromosomes fail to separate during meiosis.