BCHM 307- EXAM 2 QUESTIONS
WITH REVISED ANSWERS
Describe the features and functions of transcription factors: - Answer- Found in
eukaryotes mostly.
Helps transcription, make RNA polymerase easier to bind.
Will unwind the DNA to form transcription bubble.
TF bind to consensus sequences.
Occurs on 1 strand.
Compare and contrast features of transcription and replication: - Answer- DNA
polymerase vs RNA polymerase.
Transcription: rna-dna hybrid.
-One strand is transcribed
Replication: dna-dna b -helix.
-Both strands copied
Describe the role of bromodomain containing transcription factors in activating DNA for
transcription: - Answer- Can hyperacetylated the histones to increase the
Positive feedback, so more and more acetylation
Describe the mechanism by which enhancer elements and mediator enhance
transcription: - Answer- Enhancer = part of DNA, further upstream on DNA 5'--.
Activator = protein bound to the enhancer.
Then activator associates with mediator.
To increase gene expression and bring more TF together.
List components of transcriptional machinery that are unique to prokaryotes: - Answer-
Yeast as it.
Prokaryote:
Operons are sets of genes under control of 1 promoter.
One type of RNA polymerase.
, List components of transcriptional machinery that are unique to eukaryotes: - Answer-
will have each a gene w each promoter.
Will go thru splicing and processing.
3 types of RNA polymerases.
Describe the functions of RNA polymerase I: - Answer- transcribes rRNA
Describe the functions of RNA polymerase II: - Answer- transcribes mRNA
Describe the functions of RNA polymerase III: - Answer- transcribes tRNA
Describe the different functions of the different RNA polymerases - Answer- Eukaryotic
RNA polymerase II: mRNA
Pulls the nucleotides get pulled in
A-DNA=bent
DNA-RNA hybrid= what is made while transcription occurs
B-DNA= normal
Define processivity: - Answer- clamping so that the RNA polymerase can hold on to the
DNA.
Identify the components found in the active site of RNA polymerase: - Answer- Active
site on bottom of positive charged cleft, between 2 largest subunits.
DNA enters the cleft of RNA polymerase.
DNA is separated in the transcription bubble.
The DNA is fed thru the RNA polymerase.
Describe why RNA polymerase has two different conformations during initiation and
elongation and what mediates this conformational change: - Answer- Switches from
binding to TF and mediates (initiation), then to an elongation (2nd conformation).
RNA polymerase can work around the DNA that's on histones.
RNA polymerase will phosphorylate it's C-terminal domain.
Describe three different post translational modifications of proteins found in this week's
videos - Answer- 5' cap: guanin7 methyl cap on 5' end of mRNA.
Splicing: cuts out introns and puts exons together
PolyA: log chain of Adosine.
WITH REVISED ANSWERS
Describe the features and functions of transcription factors: - Answer- Found in
eukaryotes mostly.
Helps transcription, make RNA polymerase easier to bind.
Will unwind the DNA to form transcription bubble.
TF bind to consensus sequences.
Occurs on 1 strand.
Compare and contrast features of transcription and replication: - Answer- DNA
polymerase vs RNA polymerase.
Transcription: rna-dna hybrid.
-One strand is transcribed
Replication: dna-dna b -helix.
-Both strands copied
Describe the role of bromodomain containing transcription factors in activating DNA for
transcription: - Answer- Can hyperacetylated the histones to increase the
Positive feedback, so more and more acetylation
Describe the mechanism by which enhancer elements and mediator enhance
transcription: - Answer- Enhancer = part of DNA, further upstream on DNA 5'--.
Activator = protein bound to the enhancer.
Then activator associates with mediator.
To increase gene expression and bring more TF together.
List components of transcriptional machinery that are unique to prokaryotes: - Answer-
Yeast as it.
Prokaryote:
Operons are sets of genes under control of 1 promoter.
One type of RNA polymerase.
, List components of transcriptional machinery that are unique to eukaryotes: - Answer-
will have each a gene w each promoter.
Will go thru splicing and processing.
3 types of RNA polymerases.
Describe the functions of RNA polymerase I: - Answer- transcribes rRNA
Describe the functions of RNA polymerase II: - Answer- transcribes mRNA
Describe the functions of RNA polymerase III: - Answer- transcribes tRNA
Describe the different functions of the different RNA polymerases - Answer- Eukaryotic
RNA polymerase II: mRNA
Pulls the nucleotides get pulled in
A-DNA=bent
DNA-RNA hybrid= what is made while transcription occurs
B-DNA= normal
Define processivity: - Answer- clamping so that the RNA polymerase can hold on to the
DNA.
Identify the components found in the active site of RNA polymerase: - Answer- Active
site on bottom of positive charged cleft, between 2 largest subunits.
DNA enters the cleft of RNA polymerase.
DNA is separated in the transcription bubble.
The DNA is fed thru the RNA polymerase.
Describe why RNA polymerase has two different conformations during initiation and
elongation and what mediates this conformational change: - Answer- Switches from
binding to TF and mediates (initiation), then to an elongation (2nd conformation).
RNA polymerase can work around the DNA that's on histones.
RNA polymerase will phosphorylate it's C-terminal domain.
Describe three different post translational modifications of proteins found in this week's
videos - Answer- 5' cap: guanin7 methyl cap on 5' end of mRNA.
Splicing: cuts out introns and puts exons together
PolyA: log chain of Adosine.
