8.1 Mutations

Question 1

what is a mutation

Answer 1

• a change in DNA base sequence of chromosomes
• happen spontaneously during DNA replication

Question 2

what is rate of mutation increased by

Answer 2

mutagenic agents e.g. ionising radiation and chemicals

Question 3

what is a substitution

Answer 3

change a single base (or more) for a different one

Question 4

what do substitutions do

Answer 4

• may have no effect due degenerate genetic code - so same amino acid
• change the amino acid. This will change tertiary structure unless the chemical properties are the same
• Introduce a stop triplet code and so shorten the polypeptide chain

Question 5

what do additions and deletions cause

Answer 5

a frameshift so causes a significant change in tertiary structure

Question 6

what is an inversion

Answer 6

• section of DNA is reversed
• Changes the triplets in this region, so amino acids will be different
• Changes tertiary structure of the protein

Question 7

what is a duplication

Answer 7

• adds additional triplet codes, so more amino acids in the primary structure of the protein
• changes the tertiary structure of the protein
• could result in a frameshift

Question 8

what is a translocation

Answer 8

moves a sequence of bases to a different part of the chromosome or to a different chromosome

Question 9

what does a translocation do

Answer 9

• adds additional triplet codes in the new location, so more amino acids in the primary structure of the protein
• removes triplet codes in the original location, so fewer amino acids in the primary structure of the protein
• changes in the tertiary structure of the proteins
• could result in frameshift