5 Steps to a 5 AP Biology, 2014-2015 Edition
Molecular Genetics ❮ 131
- Which of the following is the correct sequence of
events that must occur for translation to begin?
A. Transfer RNA binds to the small ribosomal
subunit, which leads to the attachment of the
large ribosomal subunit. This signals to the
mRNA molecule that it should now bind,
with its first codon in the correct site, to the
protein synthesis machinery, and translation
begins.
B. Messenger RNA attaches to the small riboso-
mal subunit, with its first codon in the cor-
rect site, thus attracting a tRNA molecule to
attach to the codon. This signals to the large
subunit that it should now bind to the pro-
tein synthesis machinery, and translation can
begin.
C. Messenger RNA attaches to the large riboso-
mal subunit with its first codon in the correct
site, attracting a tRNA molecule to attach to
the codon. This signals to the small subunit
that it should now bind to the protein synthe-
sis machinery, and translation can begin.
D. Transfer RNA binds to the large ribosomal
subunit, which leads to the attachment of
the small ribosomal subunit. This signals to
the mRNA molecule that it should now
bind with its first codon in the correct site to
the protein synthesis machinery, and transla-
tion begins.
E. Transfer RNA attaches to the large ribosomal
subunit, which attracts the mRNA molecule
to attach with its first codon in the correct
site to the large ribosomal subunit. This sig-
nals to the small subunit that it should now
bind to the protein synthesis machinery, and
translation can begin.
7. All the following are players involved in the con-
trol of gene expression except
A. episomes.
B. repressors.
C. operons.
D. methylation.
E. hormones.
8. Which of the following does notoccur during
RNA processing in the nucleus of eukaryotes?
A. The removal of introns from the RNA
molecule
B. The addition of a string of adenine nucleotides
to the 3′end of the RNA molecule
C. The addition of a guanine cap to the 5′end
of the RNA molecule
D. The ligation of exons of the RNA molecule
E. The addition of methyl groups to certain
nucleotides of the RNA molecules
9. Which of the following statements is nottrue of
a tRNA molecule?
A. The job of transfer RNA is to carry amino
acids to the ribosomes.
B. At the attachment site of each tRNA, there
is a region called the anticodon, which is a
three-nucleotide sequence that is perfectly
complementary to a particular codon.
C. Each tRNA molecule has a short lifespan
and is used only once during translation.
D. The enzyme responsible for ensuring that a
tRNA molecule is carrying the appropriate
amino acid is aminoacyl tRNA synthase.
E. Transfer RNA is transcribed from DNA
templates within the nucleus of eukaryotic
cells.
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