Genetic Diversity + Adaptation

Question 1

What is a mutation?

Answer 1

A change in the quantity or base sequence on the DNA

Question 2

What is a gene mutation?

Answer 2

A change to one or more of the nucleotide bases/a change in the sequence of bases.

Question 3

What is substitution of bases?

Answer 3

A type of gene mutation in which a nucleotide in a DNA molecule is replaced by another nucleotide which has a different base

Question 4

What is deletion?

Answer 4

When a nucleotide is lost from the normal DNA sequence

All triplets in a sequence will be read differently as each will be shifted to the left by one base.

Question 5

What is a chromosome mutation?
+When do they happen
+What are the two forms

Answer 5

Changes in the structure of number of whole chromosomes.

Happen spontaneously

1. Changes in whole sets of chromosomes - Organisms have 3+ sets of chromosomes rather than 2, this is known as Polyploidy, which occurs mainly in plants
2. Changes in the number of individual chromosomes- Homologous pairs fail to separate during meiosis, this is called Non-disjunction, so a gamete will have one extra or one less chromosome -> an example is Down’s Syndrome (additional chromosome 21)