Chapter 6 quiz questions

A type of mutation in which a region of one chromosome is moved to a different chromosome is called __________.

translocation

In sickle cell anemia, a point mutation leads to a replacement of one amino acid in a hemoglobin molecule, in a unit responsible for transportation of oxygen. This and any other mutation in a gene that causes a change in the amino acid sequence in a polypeptide chain is known as a __________ mutation.

Missense

If an mRNA sequence in the 5'-3' direction usually begins UGG AUG UCG CCC AUA, what would you expect to happen if the guanine in the third position is deleted from the mRNA sequence?

The mRNA will not be translated into a protein at all.

The graph shows the distribution of fitness effects of Bacteriophage f1 mutants. Note that values greater than 1.0 indicate beneficial mutations, whereas values less than 1.0 indicate deleterious mutations. What is the best conclusion from this study?

The vast majority of the mutations had a deleterious effect, but some were beneficial.

Gene expression in eukaryotes is strongly influenced by the local structure of the chromosome. In which of the following regions of a DNA molecule would you expect to find the highest levels of gene expression?

decondensed chromatin

One of the important facts learned from experiments in molecular genetics is that most amino acids can be encoded by more than one nucleotide triplet. For this reason, we say that the genetic code is __________.

degenerate

In their experiment in 1943 using E. coli, Salvador Luria and Max Delbrück tested two alternative hypotheses. The random mutation hypothesis and the acquired inherited resistance hypothesis make different predictions about the distribution of resistant mutants that will be observed upon exposure to bacteriophage (viruses that can infect and kill E. coli). Which of the following predictions, if proven, would support the acquired inherited resistance hypothesis?

At the time of exposure to the phage, all E. coli cells will be phage-sensitive. The process of exposure to the phage will induce phage resistance in a small fraction of the bacterial cells.

A mutation resulting in deletion of a protein-coding gene will most likely have a ___________ effect on fitness.

Deleterious

An addition or deletion of one or two base pairs in a gene sequence results in a __________ mutation.

Frameshift