CMB Final PASSED Exam Questions and
CORRECT Answers
What is the genetic code? - Correct Answer- The genetic code is the instructions contained in
a gene that tell a cell how to make a specific protein.
What is a codon? - Correct Answer- A codon is a DNA or RNA sequence of three nucleotides
that encodes for a specific amino acid.
What is a synonymous mutation? - Correct Answer- A synonymous mutation is a change in
one base pair that still codes for the same animo acid as the wild-type allele.
What is a nonsynonymous mutation? - Correct Answer- A single base substitution causes the
amino acid to change. An example is sickle cell anemia.
What is a frameshift mutation? - Correct Answer- A mutation caused by the insertion or
deletion in a DNA sequence that shifts the way the sequence is read.
Describe the structure of tRNA. - Correct Answer- tRNA has a distinctive folded structure
with three hairpin loops that form the shape of a three leaf clover. One of the hairpins
contains the anticodon which matches with the codon on mRNA.
Explain the process of how a tRNA is charged using tRNA synthase. - Correct Answer- tRNA
synthase adds amino acids to tRNA. This occurs in a two step process. In the first step, an
amino acid and ATP are bound and form an aminoacyl-AMP intermediate and phosphate. In
the second step, the aminoacyl-AMP and tRNA are bonded and AMP is another product.
What is an anticodon? - Correct Answer- A sequence of three nucleotides forming a unit of
genetic code in a tRNA. The anticodon corresponds to compementary codon on mRNA.
Explain the wobble hypothesis. - Correct Answer- This states that the first two positions of
the codon-anticodon interactions will have normal watson-crick basepair interactions but the
third position has more leeway. Example, if CUU were misread as CUC, CUA, or CUG
during transcription, the codon would still be translated as Leu.
, Translate a stretch of DNA or RNA into amino acids using a codon table. - Correct Answer-
...
What is the start codon? - Correct Answer- AUG (Methionine)
What codons signal termination? - Correct Answer- UAA, UAG, UGA
What is the purpose of translation? - Correct Answer- The purpose of translation is to use the
information encoded in mRNA to direct the addition of amino acids during protein synthesis.
Where does translation happen in prokaryotes? Eukaryotes? - Correct Answer- In prokaryotes
both transcription and translation occur in the cytoplasm. In eukaryotes transcription occurs
in the nucleus and translation in the cytoplasm.
Identify the three stages of translation. - Correct Answer- Initiation, elongation, and
termination
Initiation in prokaryotes - Correct Answer- The small subunit of the ribosome associates with
mRNA. The initiation sequence is AUG. The Shine-Dalgarno sequence (5-10 bps upstream).
Initiations factos keep the subunit open and include IFI and IF3.
Initiation in eukaryotes - Correct Answer- Eukaryotic initiation factors bind to mRNa, the 5'
cap, and the poly-A tail and they make mRNA into a loop. Initiation involves 3 steps: small
subunit binding, aminoacyl tRNA recruitment, and assembly of the initiation complex.
rRNAs are involved by selecting tRNA, catalyzing the reactions forming the peptide bond,
and ensure accurate translation.
Elongation in prokaryotes - Correct Answer- tRNA enters the A site using EF-Tu which is an
elongation factor. Peptidyl transferase causes movement from the A to P site. Then,
hydrolysis of the GTP on EF-G+GTP causes movement into the E site.
Elongation in eukaryotes - Correct Answer- The process is the same as prokaryotic elongation
besides more elongation factors (EF-Ialpha), proteins, and it is more complex.
Termination in prokaryotes and eukaryotes - Correct Answer- The stop codons cause
termination. Release factors bind leading to disassociation of the mRNA from the ribosome.
CORRECT Answers
What is the genetic code? - Correct Answer- The genetic code is the instructions contained in
a gene that tell a cell how to make a specific protein.
What is a codon? - Correct Answer- A codon is a DNA or RNA sequence of three nucleotides
that encodes for a specific amino acid.
What is a synonymous mutation? - Correct Answer- A synonymous mutation is a change in
one base pair that still codes for the same animo acid as the wild-type allele.
What is a nonsynonymous mutation? - Correct Answer- A single base substitution causes the
amino acid to change. An example is sickle cell anemia.
What is a frameshift mutation? - Correct Answer- A mutation caused by the insertion or
deletion in a DNA sequence that shifts the way the sequence is read.
Describe the structure of tRNA. - Correct Answer- tRNA has a distinctive folded structure
with three hairpin loops that form the shape of a three leaf clover. One of the hairpins
contains the anticodon which matches with the codon on mRNA.
Explain the process of how a tRNA is charged using tRNA synthase. - Correct Answer- tRNA
synthase adds amino acids to tRNA. This occurs in a two step process. In the first step, an
amino acid and ATP are bound and form an aminoacyl-AMP intermediate and phosphate. In
the second step, the aminoacyl-AMP and tRNA are bonded and AMP is another product.
What is an anticodon? - Correct Answer- A sequence of three nucleotides forming a unit of
genetic code in a tRNA. The anticodon corresponds to compementary codon on mRNA.
Explain the wobble hypothesis. - Correct Answer- This states that the first two positions of
the codon-anticodon interactions will have normal watson-crick basepair interactions but the
third position has more leeway. Example, if CUU were misread as CUC, CUA, or CUG
during transcription, the codon would still be translated as Leu.
, Translate a stretch of DNA or RNA into amino acids using a codon table. - Correct Answer-
...
What is the start codon? - Correct Answer- AUG (Methionine)
What codons signal termination? - Correct Answer- UAA, UAG, UGA
What is the purpose of translation? - Correct Answer- The purpose of translation is to use the
information encoded in mRNA to direct the addition of amino acids during protein synthesis.
Where does translation happen in prokaryotes? Eukaryotes? - Correct Answer- In prokaryotes
both transcription and translation occur in the cytoplasm. In eukaryotes transcription occurs
in the nucleus and translation in the cytoplasm.
Identify the three stages of translation. - Correct Answer- Initiation, elongation, and
termination
Initiation in prokaryotes - Correct Answer- The small subunit of the ribosome associates with
mRNA. The initiation sequence is AUG. The Shine-Dalgarno sequence (5-10 bps upstream).
Initiations factos keep the subunit open and include IFI and IF3.
Initiation in eukaryotes - Correct Answer- Eukaryotic initiation factors bind to mRNa, the 5'
cap, and the poly-A tail and they make mRNA into a loop. Initiation involves 3 steps: small
subunit binding, aminoacyl tRNA recruitment, and assembly of the initiation complex.
rRNAs are involved by selecting tRNA, catalyzing the reactions forming the peptide bond,
and ensure accurate translation.
Elongation in prokaryotes - Correct Answer- tRNA enters the A site using EF-Tu which is an
elongation factor. Peptidyl transferase causes movement from the A to P site. Then,
hydrolysis of the GTP on EF-G+GTP causes movement into the E site.
Elongation in eukaryotes - Correct Answer- The process is the same as prokaryotic elongation
besides more elongation factors (EF-Ialpha), proteins, and it is more complex.
Termination in prokaryotes and eukaryotes - Correct Answer- The stop codons cause
termination. Release factors bind leading to disassociation of the mRNA from the ribosome.
