A triplet of bases on an mRNA molecule is known as a(n)
A) amino acid.
B) anticodon.
C) codon.
D) ribosome-binding sequence.
During DNA replication Okazaki fragments are linked together by________, an enzyme that creates phosphodiester bonds between nicked fragments of DNA.
A) exopolymerase
B) DNA gyrase
C) topoisomerase
D) DNA ligase
You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein.
One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that
A) there are two termination sites in the mRNA.
B) the protein requires chaperonins to fold properly.
C) the protein is secreted and folds outside of the cell.
D) you need to re-do the experiment because there should only be one form.
In ________ several ribosomes can simultaneously translate a single mRNA molecule in a complex called a(n) ________.
A) prokaryotes / polysome
B) eukaryotes / polysome
C) prokaryotes / initiation complex
D) eukaryotes / splicing complex
You experimentally change the DNA sequence directly upstream of a start codon of an operon in E. coli to investigate the function of this region of DNA.
Analysis reveals that after the change the same amount of mRNA is made from the operon, but there are very few proteins made from the operon. What is the most likely function of the DNA sequence that you changed?
A) The DNA sequence likely functions as a ribosome-binding site.
B) The DNA sequence likely functions as a promoter.
C) The DNA sequence likely functions as a termination sequence.
D) The DNA sequence likely functions as in transcriptional regulation.
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