Unit 7

Which of the following sequences of nucleotides are possible in the template strand of DNA that would code for the polypeptide sequence Phe-Leu-Ile-Val

A - 3'-AAA-GAA-TAA-CAA-5'

Sickle-cell anemia is associated with a mutation in the gene encoding the beta subunit of hemoglobin that results in a change from glutamic acid to valine in position 6. All other amino acids are identical to a normal hemoglobin molecules. Bases on the info above, which of the following mutations is the most likely cause of sickle-cell anemia?

A - A single base-pair substitution in the gene encoding the beta subunit.

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

A - Eukaryotic exons may be spliced in alternative patterns

Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following?

A - Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides attach.

The tryptophan operon is a repressible operon that is

A - Turned off whenever tryptophan is added to the growth medium

Which of the following removes the RNA nucleotides from the primer and adds the equivalent DNA nucleotides to the 3' end of the Okazaki fragments?

B - DNA polymerase III

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

B - Join Okazaki fragments together

Based on the bacteriophage experiment, which of the following types of molecules did the bacteriophages most likely inject into bacterial cells?

C - DNA

For a repressible operon to be transcribed, which of the following must occur?

C - RNA polymerase cannot be present, and the repressor must be inactive

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

D - 12

Insulin is a protein that is made up of 51 amino acids. It would have been translated from an mRNA transcript that had at least:

D - 153 nucleotides

The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except?

D - DNA was the first genetic material

In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?

D - RNA polymerase II

The following DNA sequence is a small part of the coding (nontemplate) strand from the open reading frame of the B-hemoglobin gene. Given the codon chart, which would be an effect of a mutation that deletes the G at the beginning of the DNA sequence?

D - The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point.

From the following list, which is the first event in translation in eukaryotes?

D - The small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA

Muscle cells and nerve cells in one species of animal owe their differences in structure to?

E - Having different genes expressed

Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?

INCORRECT

In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of?

INCORRECT

Which of the following best describes an event during step 2 (in between pre-mRNA and mRNA).?

INCORRECT