8.1 DNA and The Structure Of Proteins

Question 1

What is a mutation?

Answer 1

An alteration to the DNA base sequence. Often arise spontaneously during DNA replication

Question 2

What are addition and delation mutations?

Answer 2

Where one or more nucleotides (bases) are either inserted or deleted from the DNA sequence

Question 3

What is a substitution mutation

Answer 3

Where one nucleotide (base) in the DNA sequence is replaced by another

Question 4

What is a duplication mutation

Answer 4

Where one or more nucleotides (bases) duplicate and repeat

Question 5

What is an inversion mutation

Answer 5

Where a group of nucleotides (bases) become separated from the DNA sequence, then rejoin in the reverse order I.e. they have flipped

Question 6

What is a translocation mutation

Answer 6

Where a group of nucleotides (bases) become separated from the DNA sequence, and are then inserted into the DNA of a different chromosome

Question 7

Which mutation are most likely to have a significant impact and why?

Answer 7

Insertion, deletion, duplication, translocation. Because they produce a frameshift, meaning the

Question 8

Is a mutation resulting in a change to the amino acid sequence always harmful?

Answer 8

No; may be neutral if the resulting change in protein has no effect on the organism. Also may be beneficial, which is the basis for evolution and natural selection

Question 9

What is a mutagenic agent? Give examples of this?

Answer 9

Factors that increase the rate of gene mutation. Chemical mutagens such as alcohol and benzene. Ionising radiation such as UV and X-Ray

Question 10

Which mutation are less likely to have a significant impact and why

Answer 10

Substitution, inversion. Because they only alter one or very few triplets. The amino acid sequence might not be affected due to the degenerate nature of the genetic code