Chapter 15 Flashcards
Which of the following statements about proteins is incorrect?
a. All proteins are made up of some combination of 20 essential amino acids.
b. Like nucleic acids, polypeptides have polarity.
c. A single polypeptide has primary, secondary and tertiary structures.
d. α-helix and β-pleated sheets do not require specific sequence of amino acids to form.
e. Some proteins contain more than one polypeptide chain.
a
During initiation of translation, ________.
a. the initiator tRNAmet binds to the A site of a ribosome.
b. specific rRNA base pairs with a sequence in mRNA to position a ribosome at the start codon.
c. IF-3 must be recruited to the 30S ribosome in order for the 70S initiation complex to assemble.
d. there is no energy expenditure as the tRNA binding to mRNA is via complementary base pairing.
e. Both 70S and 30S ribosome subunits must simultaneously recognize an mRNA to bind.
b
Which of the following statements about translation is correct?
a. A special tRNA that does not have an attached amino acid binds to stop codons to terminate translation.
b. The first three bases at the 5 end of an mRNA are the AUG at which translation begins.
c. The codon for methionine appears only at the beginning of the mRNA for a protein, not in the middle or in the end.
d. In eukaryotes, the 5 cap and the 3 poly(A) tail are involved in translation initiation.
e. Ribosomes move along an mRNA in the 3 to 5 direction.
d
Which of the following is observed in prokaryotes but not in eukaryotes?
a. UGG is an example of a stop codon only found in prokaryotes.
b. An mRNA can be translated by only one ribosome at a time in prokaryotes.
c. The 5’ end of a prokaryotic mRNA can be translated while the 3 end is still being transcribed.
d. Translation does not require any protein factors in prokaryotes.
e. In prokaryotes, ribosomes move along an mRNA in the 3’ to 5’ direction.
c
Which of the following codon codes different amino acid from the rest?
a. CUU
b. CUC
c. UUA
d. UUU
e. CUA
d
Which of the following statement describes the ‘wobble’ rules correctly?
a. There is a flexible pairing between tRNA and amino acid as there are more tRNAs than the number of amino acids.
b. The number of genetic code exceeds the number of amino acids available in the cell.
c. There are multiple tRNA that may bind to the same amino acids.
d. There are multiple codons that may code for the same amino acids.
e. The third base pairing between the tRNA and mRNA is relaxed.
e
For a sequence of nucleotide, how many reading frame is possible?
a. One
b. Two
c. Three
d. Five
e. Ten
c
Which amino acid is coded by the stop codons in most organisms?
a. met
b. pro
c. trp
d. cys
e. none
e
Which of the following is not required during the process of tRNA charging?
a. amino acid
b. tRNA
c. GTP
d. ATP
e. aminoacyl-tRNA synthetase
c
Which of the following does not enhance the biding of the ribosome to the 5’ end of the mRNA?
a. 5’ cap
b. 3’ poly-A tail
c. cap binding proteins
d. poly(A) proteins
e. enhancer
e
Process 2 represents ___________.
a. replication
b. transcription
c. translation
d. RNA processing
e. RNA interference
c
If the bottom strand of the DNA from the diagram above serves as the template strand, the RNA sequence, left to right 5 to 3, is
a. AUAGGCAGU
b. UCCCAGGUG
c. CACCUGGGA
d. AGGGUCCAC
e. GACAUUAGA
a
If the bottom strand of the DNA serves as the template, the amino acid sequence of the protein produced from the RNA would be
a. met-leu-ser.
b. arg-val-his.
c. thr-ile-phe
d. pro-gly-trp
e. lys-val-his
b
If the bottom strand of the DNA is the template, the tRNA anticodon sequence, left to right 5 to 3, for the first RNA codon is
a. GGA
b. AUG
c. CAC
d. UCC
e. CCU
e
During initiation, the _____subunit is the first part of the ribosome to associate with the mRNA.
a. small
b. large
c. intermediary
d. secondary
e. tertiary
a
During elongation, an incoming charged tRNA enters at the __ site of the ribosome.
a. peptidyl (P)
b. aminoacyl (A)
c. Exit (E)
d. Shine-Delgarno
e. Kozak
b
Codons that specify the same amino acid are said to be
a. wobbly
b. isoaccepting
c. hypothetical
d. synonymous
e. anonymous
d