Genetics Exam 2 Questions

Frederick Griffith’s transformation experiment showed that

A chemical component of cells could introduce a new trait to a cell.

In Avery, MacLeod, and McCarty’s experiment, what enzyme was present in the mixture of R & S strain that when injected into the mice did not result in death?

DNase

In the Hershey and Chase phage experiment, what finding led to the conclusion that DNA is genetic material?

The presence of radioactivity in the bacteria when 32P was used

What would be the outcome of the Hershey Chase experiment if protein (and not DNA) was the carrier of genetic information?

The infected bacteria would be positive for 35S radioactive labeling, and not 32P

Which of the following is NOT consistent with Erwin Chargaff’s findings?

(C+G) = (A+T)

The virus phi X 174 infects Escherichia coli. Its base composition is as

follows:

A = 24.0 %

G = 23.3 %

C = 21.4 %

T = 31.3 %

What conclusions can you draw about phi X 174 ?

It has a singe-stranded DNA genome

In the Meselson–Stahl experiment, if DNA had been replicated conservatively,

after two rounds of replication, there would be _____.

One old, heavy band and one new, light band

All known bacterial DNA polymerase _____.

Have 5’ to 3’ polymerization activity

What ability provides DNA polymerase III the ability to proofread

Exonuclease activity in 3’ to 5’ direction

Okazaki fragments are a consequence of

The inability of DNA polymerase to polymerize in the 3’ to 5’ direction

What protein is functioning at the point marked with the arrow?

DNA polymerase III

What enzyme will replace RNA primers found in the newly synthesized strand?

DNA polymerase I

Is there any role for an RNA polymerase in DNA replication?

Yes, to generate primers.

What does the term “processive” mean in the context of DNA replication?

that length of DNA that is replicated by the core enzyme before it detaches from the template

How do bacteria package their DNA?

by supercoiling the DNA

If there were six bases in D N A and still only 20 amino acids, how long would a codon need to be in order to specify an amino acid?

Two bases

The wobble hypothesis predicts that codons coding for the same amino acid _____.

may differ at the third position

In humans, the phenylalanine hydroxylase gene is 90,000 (90 kb) bases long, yet the mRNA is only 2,400 (2.4 kb). What explains this difference?

Presence of introns in DNA

The sigma subunit of bacterial RNA polymerase _____.

binds to a bacterial gene’s promoter

An aminoacyl tRNA synthaseValine is mutated so that it now attaches the amino acid glycine to the tRNA Valine instead of valine. What will happen at translation?

There will be glycines at all glycine positions and at all valine positions.

During the elongation phase of translation, charged tRNAs enter the ribosome at the ______.

A site

Which of the following will most likely result in frameshift mutations?

Acridine orange dye

Which is NOT likely to result in double stranded breaks?

Tautomeric Shifts

Which is most likely to result in thymine dimer?

UV