chp 13 hw

Question 1

Which statements about the modification of chromatin structure in eukaryotes are​ true?

Answer 1

everything besides
- Deacetylation of histone tails in chromatin loosens the association between nucleosomes and DNA.

Question 2

The diagram below shows a segment of DNA containing an imaginary gene ​(Z​) and the primary RNA transcript that results from the transcription of gene Z. Exons are represented in green and introns are represented in blue.

Answer 2

the ones where the genes are green only
should be three correct answers

Question 3

Which of the following best describes the mechanism by which steroid hormones control gene​ expression?

a. Steroid hormones enter a​ cell, bind directly to hormone response elements​ (HREs), and enhance transcription.
b. Steroid hormones that enter the cell activate receptors. These​ hormone-receptor complexes then bind HREs and influence gene expression.
c. Steroid hormones transport mRNA from the nucleus into the​ cytoplasm, where it is translated into protein.
d. Chaperone proteins transport steroid hormones into the cell and guide them to their target genes.

Answer 3

Steroid hormones that enter the cell activate receptors. These​ hormone-receptor complexes then bind HREs and influence gene expression.

Question 4

Which of the following best describes the role of chaperone proteins in the regulation of gene expression by steroid​ hormones?

a. Chaperone proteins maintain functionality of the receptor.
b. Chaperone proteins directly enhance transcription.
c. Chaperone proteins enter the cell and bind receptor molecules.
d. Chaperone proteins activate receptor proteins.

Answer 4

Chaperone proteins maintain functionality of the receptor.

Question 5

The reason some cells respond to the presence of a steroid hormone while others do not is that​ _______.
a. the specific HRE is present only in certain cells
b. the receptors necessary for regulation differ among cells of various types
c. chaperone proteins block the hormone response elements​ (HREs) in some cells
d. only certain cells contain the gene that is targeted by a given steroid hormone

Answer 5

the receptors necessary for regulation differ among cells of various types

Question 6

__________ is a DNA sequence where RNA polymerase binds and begins the process of transcription.

Answer 6

promoters

Question 7

________ is a DNA sequence that binds regulatory proteins that interact with​ promoter-bound proteins to activate transcription.

Answer 7

enhancer

Question 8

______ is a DNA sequence that binds regulatory proteins that inhibit transcription.

Answer 8

silencer

Question 9

______ is the protein complex that is part of the RNA interference ​(RNAi​) mechanism. It denatures short​ double-stranded RNAs to single strands that carry out RNAi.

Answer 9

RISC

Question 10

________ is the enzyme complex that is active in RNA​i, where it cuts​ double-stranded regulatory RNAs into ​21-bp to ​26-bp segments that are subsequently denatured by RISC.

Answer 10

DICER

Question 11

What general role does acetylation of histone protein amino acids play in the transcription of eukaryotic​ genes?
a. Histone acetylation events are most often associated with transcription repression.
b. Histone acetylation events are most often associated with transcription activation.
Your answer is correct.
c. Histone acetylation events are most often associated with transcription termination.
d. Histone acetylation events are most often associated with transcription proofreading.

Answer 11

Histone acetylation events are most often associated with transcription activation.

Question 12

promoter sequence is likely to​ be:
Check all that apply.
a. located within a few dozens nucleotides of the gene it controls
b. located either nearby or at great distance from the gene it controls
c. located upstream of the gene it controls
d. located downstream of the gene it controls
e. orientation independent
f. orientation dependent

Answer 12

located within a few dozens nucleotides of the gene it controls

located upstream of the gene it controls

orientation dependent

Question 13

enhancer sequence is likely to​ be:
Check all that apply.
a. located either nearby or at great distance from the gene it controls
b. located upstream of the gene it controls
c. located within a few dozens nucleotides of the gene it controls
d. located downstream of the gene it controls
e. orientation independent
f. orientation dependent

Answer 13

located either nearby or at great distance from the gene it controls

located upstream of the gene it controls

located downstream of the gene it controls

orientation independent

Question 14

Choose the correct definition of epigenetics.
a. Epigenetic refers to heritable patterns of a​ gene’s transcription activity.
b. Epigenetic refers to heritable​ traits, the expression of which is strongly dependent on environmental factors.
c. Epigenetic refers to heritable traits encoded by extrachromosomal genes​ (such as those of mitochondrial​ genes).
d. Epigenetic refers to heritable states of chromatin structure.

Answer 14

d. Epigenetic refers to heritable states of chromatin structure.

Question 15

List examples illustrating the phenomenon.
Select all that apply.
a. Klinefelter syndrome
​b. Prader-Willi syndrome
c. Down syndrome
d. Angelman syndrome
e. Turner syndrome

Answer 15

​b. Prader-Willi syndrome
d. Angelman syndrome

Question 16

Based on your​ analysis, what is the most likely molecular abnormality causing the disease​ allele?
a. A​ pre-mRNA spicing mutation causes a deletion of exon 1.
b. A​ pre-mRNA spicing mutation causes a deletion of exon 2.
c. A​ pre-mRNA spicing mutation causes a deletion of exon 3.
d. A​ pre-mRNA spicing mutation causes a deletion of exon 4.

Answer 16

A​ pre-mRNA spicing mutation causes a deletion of exon 3.

Question 17

Does this information indicate the presence of enhancer​ and/or silencer sequences in the ME1 upstream​ sequence?
yes
noe

Answer 17

yes

Question 18

Where is the enhancer sequence​ located?

Answer 18

6

Question 19

Where is the silencer sequence​ located?

Answer 19

9

Question 20

Why does deletion D effectively eliminate transcription of lacZ​?
a. the deletion removes a silencer
b. the deletion removes a part of coding region
c. the deletion removes the promoter
d. the deletion removes an enhancer element

Answer 20

c. the deletion removes the promoter

Question 21

Given the information available from deletion​ analysis, can you give a molecular explanation for the observation that ME 1 expression appears to turn on and turn off at various times during normal mouse​ development?

a. Expression of ME 1 is regulated by an enhancer and a​ silencer, which can be regulated such that ME 1 expression is activated at some developmental stages and then repressed at others.

b. Expression of ME 1 is regulated by a promoter and an​ inhibitor, which can be regulated such that ME 1 expression is activated at some developmental stages and then repressed at others.

c. Expression of ME 1 is a​ non-regulated process which is turned on and turned off randomly.

d. None of the above.

Answer 21

a. Expression of ME 1 is regulated by an enhancer and a​ silencer, which can be regulated such that ME 1 expression is activated at some developmental stages and then repressed at others.

Question 22

How many regions in the DNA sequences have been conserved among all three​ species?

Answer 22

three

Question 23

In​ general, DNA regions that are conserved between​ distantly-related species provide evidence of conserved _______

Answer 23

function

Question 24

Regulatory DNA that is conserved between​ distantly-related species may function as regions that bind ______ ______

Answer 24

regulatory proteins

Question 25

From these​ results, you hypothesize that the sequence you have examined contains a promoter for gene 1 ​(P Subscript 1​), an enhancer that controls antennal expression ​(E Subscript A​), an enhancer that controls leg and wing expression ​(E Subscript WL​), and an insulator region​ (I).

Answer 25

A. P1
B. EA
C. I
D. EWL

Question 26

For which gene or genes does the insulator region act as an​ insulator?

Answer 26

gene 1 & 2

Question 27

How many enhancers control the expression of Gene 2 in wing and leg​ discs?

Answer 27

two enhancers, one for each disc type

Question 28

Use the expression data for constructs 8​ - 13 from Part B​ (repeated below) to determine the locations of E Subscript W and E Subscript L​, as well as the promoter for Gene 2 ​(P Subscript 2​).

Answer 28

A. EW
B. EL
C. P2