week 6-ch.6

If one human protein contains 400 amino acids, how many nucleotides need to be in the exons of the corresponding gene to properly code for it?

1200

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

frameshift

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

A mutation in DNA that does not change the protein produced is known as a _____________ Mutation.

synonymous

Which position in a codon shows the greatest degeneracy? In other words, if a change occurs in this codon position, it is less likely to change the amino acid that is specified relative to the other positions.

third position

A mutation that results in a replacement of a purine with a pyrimidine is known as a __________ mutation.

transversion

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

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

deleterious

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.

Which of the following is TRUE regarding the difference between a DNA molecule and an RNA molecule?

DNA is a double-stranded molecule, whereas RNA is a single-stranded molecule.