Topic 3 - Mutation & Variation

Question 1

What are genetic variants?

Answer 1

Small changes in the order of bases that make up a strand of DNA

Question 2

What do genetic variants on coding DNA cause?

Answer 2

1. Alters the sequence of bases
2. Changes the sequence of amino acids and the shape of the final protein’s structure

Question 3

What do genetic variants on non-coding DNA cause?

Answer 3

1. Affects how much RNA polymerase can bind to the DNA
2. Affects which genes are expressed
3. Alters the quantity of protein that can be synthesised

Question 4

What are the types of mutation?

Answer 4

• Insertion - a base is inserted into the code, altering the sequence of bases/codons after
• Deletion - a base is deleted from the code, altering the sequence of bases/codons after
• Substitution - a base is substituted for another, altering a maximum of one amino acid produced

Question 5

True or False: Most mutations in DNA are silent mutations (don’t affect the individual’s corresponding phenotype)

Answer 5

True

Question 6

What is genetic variation?

Answer 6

Different characteristics arise as a result of both random mutation and sexual reproduction. Random mutation occurs in gametes to produce offspring with brand new phenotypic features. Sexual reproduction results in offspring having a combination of their parents’ phenotypic features

Question 7

What is environmental variation?

Answer 7

Different characteristics arise from external factors that don’t affect the genes of the individual