7.1 Mutations: Primary Tools of Genetic Analysis

Question 1

What are mutations

Answer 1

They are changes in the DNA base sequences

Question 2

What does a forward mutation do?

Answer 2

It changes the wild-type allele to a different allele.

Question 3

What does a reverse mutation (reversion) do?

Answer 3

It changes a mutant allele back to the wild-type allele

Question 4

What are the 3 classifications of mutations by effect on the DNA molecule? (point mutations)

Answer 4

substitution, insertion, Deletion

Question 5

What is a substitution mutation

Answer 5

It is when a specific base is replaced by another different base

Question 6

What are the two types of substitution mutations

Answer 6

Transition and transversion

Question 7

Explain what a transversion mutation is

Answer 7

It is when a purine is replaced by a pyrimidine or vice versa.

Question 8

Explain what a transition mutation is

Answer 8

It is when a purine is replaced by another purine or when a pyrimidine is replaced by a different pyrimidine

Question 9

What is a deletion mutation

Answer 9

It is when a block of 1 or more base pairs are lost from DNA

Question 10

What is an insertion mutation

Answer 10

It is when a block of 1 or more base pairs are added to DNA

Question 11

What are two facts about spontaneous mutations

Answer 11

They occurvat a very low rate and arise from random events

Question 12

true or false: different genes= different mutation rates

Answer 12

true

Question 13

Mutations are _________ per gene per gamete

Answer 13

<10^-9 to> 10^-3

Question 14

Why is it that different genes have different mutation rates? (2)

Answer 14

1. Differences in gene size
2. Some genes are more susceptible to mutations

Question 15

true or false: The average mutation rate in gamete producing eukaryotes is less than that of prokaryotes

Answer 15

false, it is higer

Question 16

why is the average mutation rate in gamete-producing eukaryotes is higher than that of prokaryotes?

Answer 16

Many cell divisions take place between zygote formation and meiosis in germ cells, which increases the chance of errors= higher chance of mutations

Question 17

Why can diploid organisms tolerate more mutations than haploid organisms

Answer 17

This is because diploid organisms have two copies of the genome while haploid organisms have one copy.

Question 18

Why is it that human sperm have higher mutation rates than human eggs

Answer 18

This is because male germ cells undergo mitosis continuously. Hence there are more mutations in the sperm of older men

Question 19

true or false: most mutations don’t influence phenotype

Answer 19

true

Question 20

true or false: revertants are more common than forward mutations

Answer 20

false, they are more rare. Many mutation disrupt gene function, only a few restore function

Question 21

define colony

Answer 21

a visible mass of microorganisms that are all genetically identical and come from a single mother cell