Which of the following enzymes relieves the strain in DNA introduced by unwinding in E. coli?
A. gyrase
B. ligase
C. primase
D. helicase
E. SSB
Poliovirus is an RNA virus that uses host cell ribosomes to synthesize a polyprotein immediately after entering the cell. In order for functional viral proteins to be produced, one would expect to observe the mechanism of:
A. phosphorylation.
B. protein methylation.
C. autoinhibition.
D. ADP-ribosylation.
E. proteolytic cleavage.
A woman has breast cancer. Evaluating the tumor cells' transcriptome may reveal:
A. her prognosis.
B. her response to specific therapies.
C. changes in rRNA as the tumor grows.
D. both her prognosis and response to specific therapies.
E. both her response to specific therapies and changes in rRNA as the tumor grows.
Matsumara et al. showed that disulfide bonds create a more stable mutant T4 lysozyme. They inserted pairs of Cys residues into the T4 lysozyme sequence and observed that:
A. the reduction of cysteine residues created a protein that denatured at lower temperatures than wild-type lysozyme.
B. the reduction of cysteine residues created a protein that was stable at higher temperatures than wild-type lysozyme.
C. the oxidation of cysteine residues created a protein that denatured at lower temperatures than wild-type lysozyme.
D. the oxidation of cysteine residues created a protein that was stable at higher temperatures than wild-type lysozyme.
E. None of these choices is correct.
Which of the following enzymes unwinds the DNA helix during replication in E. coli?
A. primase
B. DNA Pol I
C. gyrase
D. helicase
E. SSB
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