bio chap 14

Question 1

Generally speaking, a nucleotide substitution has less severe consequences than a nucleotide addition/deletion.

Answer 1

true

Question 2

Any DNA “damage” is considered to be a mutation, even if it is immediately correct by the action of DNA polymerase.

Answer 2

false

Question 3

Spontaneous mutations that occur in somatic cells will be transmitted to offspring.

Answer 3

false

Question 4

When comparing DNA sequences of similar genes for proteins in related species, you see that some of the sequences are longer in one species compared to the other. Which of the following would most likely represent the extra number of bases that you would see?

Answer 4

21

Question 5

Genetic risk factors:

Answer 5

can increase the likelihood of somatic mutations.
can increase the likelihood of germ-line mutations.
can work synergistically with environmental risk factors.
can be heritable.

Question 6

Any deviation in normal gene dosage is lethal.

Answer 6

false

Question 7

The amount of new mutations in living organisms following a round of genome replication:

Answer 7

generally increases with larger genomes.

Question 8

Imagine that a researcher is studying a mouse that carries a mutation in Pax7 ―a gene that is involved in muscle development. To his surprise, these Pax7 mutant mice appear relatively “normal.” What is a possible explanation for this?

Answer 8

Other members of the Pax gene family have redundant functions in muscle development (and can compensate for the Pax7 mutation).
The normal copy of Pax7 on the corresponding homologous chromosome is sufficient for mouse survival.
These Pax7 mutant mice may have a synonymous mutation.

Question 9

The use of antibiotics is creating the mutations in bacteria that make them resistant to these antibiotics.

Answer 9

false

Question 10

A trinucleotide of 5’CTC3’ or 5’TTC3’ is transcribed and then translated into the amino acid glutamic acid. A trinucleotide of 5’CAA3’ or 5’TAC3’ is transcribed and then translated into valine. In sickle-cell hemoglobin, valine is present instead of glutamic acid. Assuming a single base pair substitution has occurred, what is the mRNA code for valine in the affected mutant?

Answer 10

GUA

Question 11

What is one reason that RNA viruses and retroviruses have such a high rate of mutation?

Answer 11

because RNA is more fragile than DNA and because viral polymerases lack a proofreading mechanism.

Question 12

The fact that humans have a relatively large number of mutations per genome per generation when compared to other organisms can be explained by:

Answer 12

most of a human’s DNA is noncoding, so most of the mutations are neutral.

Question 13

Normally in corn, genes for waxy and virescent kernel appearance are linked. In a certain stock, however, it was found that these two genes assort independently. Which chromosomal aberration would explain this?

Answer 13

TRANSLOCATION

Question 14

_____ is the process where new genes evolve from duplicates of old ones.

Answer 14

Duplication and divergence

Question 15

Which of the following would best describe the results seen in a flower whose sectors have different pigmentation?

Answer 15

the result of transposable elements

Question 16

Which of the following statements concerning cancer and mutations is correct?

Answer 16

Usually multiple mutations are required in different genes to cause cancer.

Question 17

Mutation rates (of nucleotides):

Answer 17

are highest in viruses.

Question 18

Which of the following would you expect to have the lowest nucleotide mutation rate?

Answer 18

HUMANS

Question 19

The rates of evolutionary change in DNA:

Answer 19

are highly variable among different gene families.

Question 20

Consider a polyploid plant that has several copies of each of its genes. This plant will likely die prematurely, given this high gene dosage.

Answer 20

FALSE

Question 21

A researcher has carried out Giesma staining on a set of human chromosomes, and has arranged these chromosomes into a karyotype. She notices that in a homologous pair, a band is missing from one of the chromosomes. This likely resulted from:

Answer 21

either a deletion or a reciprocal translocation.

Question 22

Even though the chance of a mutation for one given nucleotide is rare, mutations are rather common when looking at the whole genome.

Answer 22

TRUE

Question 23

Spontaneous mutations that occur in somatic cells will be transmitted to offspring.

Answer 23

FALSE