Molecular Biology test exam
questions and answers graded A+
What are the three steps of Translation? - ANS✅✅initiation, elongation, termination
What occurs in Translational Initiation? - ANS✅✅1. Small subunit binds to the 5' cap and scans
towards the 3' end until it hits an AUG codon.
2. tRNA (with methionine) locks into the P-site of the ribosome as the larger subunit comes and
binds to the smaller subunit
What occurs in Translational Elongation? - ANS✅✅1. A second tRNA with an amino acid binds to
the vacant A-site.
2. The methionine from tRNA on the P-site transfers to the tRNA on the A-site, causing the formation
of a tRNA with a dipeptide attached.
3. The ribosome moves down three nucleotides, shifting the empty tRNA into the E-site, and the
dipeptide tRNA to the P-site
4. The tRNA in the E-site leaves to find another Methionine, the tRNA in the P-site gives its two
amino acids to the next tRNA in the A-site.
5. This repeats until the Ribosome reaches a stop codon
What occurs in Translational Termination? - ANS✅✅1. The Release Factor Protein binds to the
stop codon in the A-site.
2. tRNA at P-site dissociate, breaking the phosphoester bond, releasing the amino acid sequence.
3. The subunits dissociate.
What is the size of a large ribosomal subunit in Eukaryotes? - ANS✅✅60s
, What is the size of a small ribosomal subunit in Eukaryotes? - ANS✅✅40s
What is the size of a Ribosomal dimer in Eukaryotes? - ANS✅✅80s
What is the size of a large ribosomal subunit in Prokaryotes? - ANS✅✅50s
What is the size of a small ribosomal subunit in Prokaryotes? - ANS✅✅30s
What is the size of a Ribosomal Dimer in Prokaryotes? - ANS✅✅70s
Where is the tataaa box located? - ANS✅✅Promoter region
What is the start codon sequence? - ANS✅✅ATG
What is the name of the region that encompasses everything from the start codon, to the end of
translation? - ANS✅✅Open Reading Frame
What happens in Eukaryotic Transcriptional Initiation? - ANS✅✅General transcription factor
(gnTF) recognize the promoter region and bind to it.
Those gnTF's recruit more of themselves, and recruit RNA polymerase.
The gnTF's determine which strand is the template strand by identifying the tataaa box
What happens in Prokaryotic Transcriptional Initiation? - ANS✅✅Sigma factors bind to the
promoter region (Prokaryotes do not have tataaa boxes)
What happens in Eukaryotic Transcriptional Elongation? - ANS✅✅1. RNA Polymerase unwinds
DNA and detects the template strand, where is then starts to create a complimentary RNA strand.
2. The RNA strand is then capped at the 5' end with 7-methyl-guanosine to prevent degradation
questions and answers graded A+
What are the three steps of Translation? - ANS✅✅initiation, elongation, termination
What occurs in Translational Initiation? - ANS✅✅1. Small subunit binds to the 5' cap and scans
towards the 3' end until it hits an AUG codon.
2. tRNA (with methionine) locks into the P-site of the ribosome as the larger subunit comes and
binds to the smaller subunit
What occurs in Translational Elongation? - ANS✅✅1. A second tRNA with an amino acid binds to
the vacant A-site.
2. The methionine from tRNA on the P-site transfers to the tRNA on the A-site, causing the formation
of a tRNA with a dipeptide attached.
3. The ribosome moves down three nucleotides, shifting the empty tRNA into the E-site, and the
dipeptide tRNA to the P-site
4. The tRNA in the E-site leaves to find another Methionine, the tRNA in the P-site gives its two
amino acids to the next tRNA in the A-site.
5. This repeats until the Ribosome reaches a stop codon
What occurs in Translational Termination? - ANS✅✅1. The Release Factor Protein binds to the
stop codon in the A-site.
2. tRNA at P-site dissociate, breaking the phosphoester bond, releasing the amino acid sequence.
3. The subunits dissociate.
What is the size of a large ribosomal subunit in Eukaryotes? - ANS✅✅60s
, What is the size of a small ribosomal subunit in Eukaryotes? - ANS✅✅40s
What is the size of a Ribosomal dimer in Eukaryotes? - ANS✅✅80s
What is the size of a large ribosomal subunit in Prokaryotes? - ANS✅✅50s
What is the size of a small ribosomal subunit in Prokaryotes? - ANS✅✅30s
What is the size of a Ribosomal Dimer in Prokaryotes? - ANS✅✅70s
Where is the tataaa box located? - ANS✅✅Promoter region
What is the start codon sequence? - ANS✅✅ATG
What is the name of the region that encompasses everything from the start codon, to the end of
translation? - ANS✅✅Open Reading Frame
What happens in Eukaryotic Transcriptional Initiation? - ANS✅✅General transcription factor
(gnTF) recognize the promoter region and bind to it.
Those gnTF's recruit more of themselves, and recruit RNA polymerase.
The gnTF's determine which strand is the template strand by identifying the tataaa box
What happens in Prokaryotic Transcriptional Initiation? - ANS✅✅Sigma factors bind to the
promoter region (Prokaryotes do not have tataaa boxes)
What happens in Eukaryotic Transcriptional Elongation? - ANS✅✅1. RNA Polymerase unwinds
DNA and detects the template strand, where is then starts to create a complimentary RNA strand.
2. The RNA strand is then capped at the 5' end with 7-methyl-guanosine to prevent degradation
