BIO 200 EXAM 3 UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Question:
1. gene
Answer:
a nucleotide sequence that allows the production of one or morle related RNAs
or polypeptides
Question:
2. constitutive expression
Answer:
gene is always on
Question:
3. gene expression
Answer:
To transcribe it into a functional RNA molecule
occurs when a protein or other gene product becomes active
Question:
4. differential gene expression
Answer:
cells with the same genome express different sets of genes
results largely from the production or activation of specific transcription factors.
turned on by enhancers and off by silencers. Also turned off when a transcription
factor is not present or chromatin is condensed)
Question:
5. general transcription factors
Answer:
interact with the core promoter
not restricted to a particular gene (ex: TBP)
,Question:
6. large complex of proteins
bridge between regulatory transcription factos, general transcription factors, and
RNA pol II. Delivers a signal to RNA pol to initiate transcription.
Answer:
mediator
Question:
7. affinity of a protein
Answer:
strength of binding to a target. binds to a specific enhancer sequence because of
complementary interactions between amino acids and base pairs in DNA.
Question:
8. transcription initiation in eukaryotes
Answer:
1) transcriptional activators bind to DNA and recruit chromatin remodeling and
HATs
2) open chromatin to expose region with core promoter, promoter proximal
elements, and enhancers
3)transcriptional activators bind to enhancers the proximals. DNA is looped.
Mediator and activators come together
4) general transcription factors and RNA pol II assemble on mediator and
associate with core promoter. Transcription begins.
Question:
9. If a presence of a cofactor tends to slow the ribosome,
then this is best characterized as an example of...
Answer:
translational regulation
, Question:
10. If the absence of a protein tends to transcribe a gene
more frequently, then this is best characterized as an
example of...
Answer:
transcriptional regulation
Question:
11. If a response to sunlight tends to alter an existing protein
structure to be more active, then this is best
characterized as an example of...
Answer:
post-translational regualtion
Question:
12. Why are some genes constitutively expressed while the
expression of others is regulated?
Answer:
Some gene products are needed at all times, and other gene products are only
produced under some conditions to avoid waste and respond to stimuli.
While there are some genes that should be 'on' as much as possible, most genes
are used only when the situation is correct. This helps avoid wastefully producing
mRNA and protein when unnecessary (both mRNA and protein require many ATP
to make a single molecule). This also allows the cell to respond appropriately to
changing conditions.
Question:
13. operator
Answer:
Polymerase-blocking proteins, such as the LacI (repressor) protein, bind at these
sites to physically block movement of the transcribing RNA polymerase.
The repressor protein can physically block transcription by binding at the
operator (between the transcriptional starting point and the mRNA sequence).
CORRECT ANSWERS
Question:
1. gene
Answer:
a nucleotide sequence that allows the production of one or morle related RNAs
or polypeptides
Question:
2. constitutive expression
Answer:
gene is always on
Question:
3. gene expression
Answer:
To transcribe it into a functional RNA molecule
occurs when a protein or other gene product becomes active
Question:
4. differential gene expression
Answer:
cells with the same genome express different sets of genes
results largely from the production or activation of specific transcription factors.
turned on by enhancers and off by silencers. Also turned off when a transcription
factor is not present or chromatin is condensed)
Question:
5. general transcription factors
Answer:
interact with the core promoter
not restricted to a particular gene (ex: TBP)
,Question:
6. large complex of proteins
bridge between regulatory transcription factos, general transcription factors, and
RNA pol II. Delivers a signal to RNA pol to initiate transcription.
Answer:
mediator
Question:
7. affinity of a protein
Answer:
strength of binding to a target. binds to a specific enhancer sequence because of
complementary interactions between amino acids and base pairs in DNA.
Question:
8. transcription initiation in eukaryotes
Answer:
1) transcriptional activators bind to DNA and recruit chromatin remodeling and
HATs
2) open chromatin to expose region with core promoter, promoter proximal
elements, and enhancers
3)transcriptional activators bind to enhancers the proximals. DNA is looped.
Mediator and activators come together
4) general transcription factors and RNA pol II assemble on mediator and
associate with core promoter. Transcription begins.
Question:
9. If a presence of a cofactor tends to slow the ribosome,
then this is best characterized as an example of...
Answer:
translational regulation
, Question:
10. If the absence of a protein tends to transcribe a gene
more frequently, then this is best characterized as an
example of...
Answer:
transcriptional regulation
Question:
11. If a response to sunlight tends to alter an existing protein
structure to be more active, then this is best
characterized as an example of...
Answer:
post-translational regualtion
Question:
12. Why are some genes constitutively expressed while the
expression of others is regulated?
Answer:
Some gene products are needed at all times, and other gene products are only
produced under some conditions to avoid waste and respond to stimuli.
While there are some genes that should be 'on' as much as possible, most genes
are used only when the situation is correct. This helps avoid wastefully producing
mRNA and protein when unnecessary (both mRNA and protein require many ATP
to make a single molecule). This also allows the cell to respond appropriately to
changing conditions.
Question:
13. operator
Answer:
Polymerase-blocking proteins, such as the LacI (repressor) protein, bind at these
sites to physically block movement of the transcribing RNA polymerase.
The repressor protein can physically block transcription by binding at the
operator (between the transcriptional starting point and the mRNA sequence).
