Genetics : Central Dogma of Biology
Study concepts, example questions & explanations for Genetics
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Example Questions
Example Question #21 : Central Dogma Of Biology
Which of the following occurs during the initiation phase of transcription?
mRNA, initiator tRNA, and ribosome subunits associate to form a complex.
RNA polymerase joins the ribonucleoside triphosphates to form an mRNA strand.
RNA polymerase continues to enlogate until it reaches the terminator sequence.
RNA polymerase binds to DNA at the promoter sequence.
The DNA double helix reforms.
RNA polymerase binds to DNA at the promoter sequence.
While many of the answer choices deal with the process of transcription, only one corresponds to the initiation stage. The joining of ribonucleotides, the reformation of the double helix, and elongation until the termination sequence occur during the elongation and termination stages of transcription. During the initiation stage of transcription, the RNA polymerase enzyme binds to DNA at the promoter sequence and then begins to unwind the DNA. The only answer choice that fits this definition is "RNA polymerase binds to DNA at the promoter sequence."
Example Question #22 : Central Dogma Of Biology
Where is the Shine-Dalgarno sequence found?
On mRNA, downstream of the start codon
On the small ribosomal subunit
On mRNA, upstream of the start codon
On the large ribosomal subunit
On the initiator tRNA
On mRNA, upstream of the start codon
The Shine-Dalgarno sequence is a ribosomal binding site in prokaryotic mRNA located upstream of the start codon. The role of the Shine-Dalgarno sequence is to help recruit the ribosome to the mRNA to initiate protein synthesis. The only answer that matches the proper location of the Shine-Dalgarno sequence is "On mRNA upstream of the start codon."
Example Question #23 : Central Dogma Of Biology
Which of the following does NOT play a role in the initiation of translation?
RNA polymerase
All of the above are involved
mRNA
Ribosomal subunits
Initiator RNA
RNA polymerase
During translation initiation, mRNA, initiator tRNA, and both small and large ribosomal subunits associate with each other to form a translation complex. RNA polymerase acts to produce RNA using DNA as a template and does not play any role in the process of translation initiation. Therefore, the correct answer is "RNA polymerase."
Example Question #24 : Central Dogma Of Biology
Which of the following is not part of the central dogma of biology?
Protein --> RNA
All of the other answers are correct.
RNA --> DNA
RNA --> Protein
DNA --> RNA
Protein --> RNA
The central dogma of biology can be summarized as "DNA --> RNA --> Protein"; however, one can also go from RNA to DNA using reverse transcriptase. This is also part of the central dogma.
Example Question #181 : Genetics
In what direction is RNA transcribed?
by base-pair size
5' to 5' direction
3' to 5' direction
5' to 3' direction
3' to 3' direction
5' to 3' direction
RNA is transcribed 5' to 3' ALWAYS, meaning that the template DNA strand is read from the 3' to 5' direction.
Example Question #25 : Central Dogma Of Biology
What are the 3 primary elements of eukaryotic mRNAs in order?
5’ UTR region, 3’ UTR region, coding sequence
3’ UTR region, 5’ UTR region, coding sequence
3’ UTR region, coding sequence, 5’ UTR region
5’ UTR region, coding sequence, 3’ UTR region
coding sequence, 3’ UTR region, 5’ UTR region
5’ UTR region, coding sequence, 3’ UTR region
The 5’ UTR region is known as the leader sequence and runs upstream from the coding sequence. The 3’ UTR region is the trailer sequence and runs downstream to the coding sequence. The start codon runs after the 5’ UTR region and the stop codon is seen prior to the 3’ UTR region.
Example Question #182 : Genetics
Eukaryotic mRNA processing requires what steps?
adding poly A tail
removal of introns (splicing)
adding the 5’ cap
all steps listed
none of the answers
all steps listed
mRNA processing includes capping (5’ cap), polyadenylation (3’ Poly A tail), and splicing (removal of introns).
Example Question #182 : Genetics
Prokaryotic and eukaryotic cells have how many RNA polymerases, respectively?
1,1
1,3
0,1
3,1
3,3
1,3
Eukaryotes are more complex cells than prokaryotes and have 3 different polymerases for the different RNA classes, while prokaryotes only have one RNA polymerase that handles RNA transcription for the whole cell.
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