Protein and Protein Functions
Transcription vs Replication
Transcription Mechanism
DNA Replication Mechanism
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100
What are the two polymerases (RNA polymerase and DNA polymerase) main functions?
Elongates the 3' end of the growing strand.
100
State and define the three steps shared by the mechanisms of DNA replication and Transcription
Initiation, elongation, termination.
Please take a look at the explanations in the "Questions and Answers" document.
100
What regions are included in an RNA transcript?
The transcription start site, the gene, and the terminator.
100
The lagging strand is slower than the leading strand, why?
The lagging strand performs more tasks than the leading strand.
100
True or false? In transcription, only the top strand of the DNA is the template strand in eukaryotes, and in prokaryotes, only the bottom strand is the template strand.
False
200
True or false? Sigma factor binds to the DNA through PD-PD non-covalent interactions
False
200
State and compare the possible products of DNA replication and transcription, respectively
Replication: 2 identical daughter strands
Transcription: mRNA transcripts, non coding mRNA, (pre-tRNA, pre-rRNA)
200
What problems can the cell encounter while replicating or transcribing DNA? Why are these issues critical, and how does the cell get around them?
Directionality of the lagging strand, breaking apart the DNA strands, the commencement of transcription.
Please look at the "Questions and Answers" document for more information.
200
What bond or interaction does DNA Ligase create between Okazaki fragments? What is the significance of it?
Phosphodiester bonds. Without DNA Ligase, the daughter DNA molecule arising from the lagging strand would not be structurally sound.
200
In which phases of the bacterial growth curve do replication and transcription occur?
Replication occurs in the log and stationary phases while DNA replication occurs in the log, lag, and stationary phases.
300
Compare and contrast the proteins that are involved in Replication and Transcription:
Topoisomerase, Sigma factor (bacterial transcription) / TATA Binding Protein and transcription factors (eukaryotic transcription), Helicase, RNA Polymerase, RNA Primase, Single-Stranded Binding Proteins, DNA Polymerase III, DNA Polymerase I, and DNA Ligase.
Please look at the "Questions and Answers" document for more detail.
300
True or false? In DNA replication, the DNA is the template, but in transcription, the RNA is the template.
False.
300
Prokaryotes and eukaryotes have different transcription initiation processes. What are the differences between the two?
Prokaryotic cells need sigma factors while eukaryotic cells need enhancers and transcriptional activator proteins.
300
True or false? DNA ligase links the Okazaki fragments together and also checks if the complementary base pairing was correct.
False
300
In what way does replication of circular DNA differ from replicating linear DNA?
There is only one origin of replication.
400
If the gene for Single-Stranded Binding proteins was mutated, what effect would this have on DNA Replication and Transcription?
This mutation would complicate or stop DNA replication and transcription.
400
True or false? it is more likely for a mutation to occur during transcription compared to DNA replication.
True.
400
Which way is transcription going? Explain your thought process.
To the right.
400
If the topoisomerase were to disappear, what effect would this have on the DNA?
The DNA would be supercoiled.
400
RNA nucleotides are responsible for a part of DNA replication. Why?
Required for DNA Polymerase III to start synthesis.
500
How might the absence of DNA Ligase affect DNA replication and transcription and their products?
In the absence of DNA Ligase, the daughter strands would be completely fragmented.
500
Why do nucleotides only grow in the 3’-5’ direction?
Due to the polarity of the DNA strand, the incoming nucleotides must attach to the 3’ end where there is a hydroxyl group.
500
If in an experiment, the RNA transcript degraded and became shorter after it left the nucleus, which step did the transcript miss when modifying the RNA transcript?
Polyadenylation.
500
In which phase of mitosis do cells undergo DNA replication?
Interphase
500
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