Question 1

List five levels at which control of gene activity can take place in eukaryotes.

Accepted Answer

In eukaryotic cells, gene activity is re

Question 2

Explain how the poly(A)-binding protein that binds to the poly(A) tails located in the 3' end of an mRNA can play a key role in an mRNA degradation pathway that proceeds from the 5'end of an mRNA in a 5'$\rightarrow$  3' direction.

Accepted Answer

The poly(A)-binding protein plays a key

Question 3

Histone methylation can have many different effects on gene expression. In some cases, histone methylation is associated with activation of transcription, whereas in other cases it can trigger the formation of heterochromatin and a decrease in transcription. If histone methylation has been detected in the region of gene X in yeast, describe an experiment that could distinguish whether the methylation is important to activate or repress transcription of gene X.

Accepted Answer

One possible experiment to distinguish w

Question 4

Proteins that affect the structure of DNA bound to histones without altering histone chemical structure are called:

Accepted Answer

A)  RISCs. 
B)  chromatin-remodeling complexes. 
C)  splicing complexes. 
D)  MRE activator proteins. 
E)  dicers. 
A)  RISCs. 
B)  chromatin-remodeling complexes. 
C)  splicing complexes. 
D)  MRE activator proteins. 
E)  dicers.

Question 5

Define RNA silencing (or interference). Explain how siRNAs arise and how they potentially affect gene expression. How are siRNAs different from the antisense RNA mechanism?

Accepted Answer

RNA silencing, also known as RNA interfe

Question 6

If a deacetylase inhibitor were injected into a mouse brain, which of the following would you expect to occur?

Accepted Answer

A)  A general increase in gene expression would occur. 
B)  A general decrease in gene expression would occur. 
C)  A general increase or decrease in gene expression, depending on the gene, would occur. 
D)  Acetyl groups would be removed from histones. 
E)  Methyl groups would be removed from the DNA. 
A)  A general increase in gene expression would occur. 
B)  A general decrease in gene expression would occur. 
C)  A general increase or decrease in gene expression, depending on the gene, would occur. 
D)  Acetyl groups would be removed from histones. 
E)  Methyl groups would be removed from the DNA.

Question 7

Which type of control is illustrated by GAL4 in the control of genes for yeast galactose-metabolizing enzymes?

Accepted Answer

A)  negative inducible 
B)  negative repressible 
C)  positive inducible 
D)  positive repressible 
A)  negative inducible 
B)  negative repressible 
C)  positive inducible 
D)  positive repressible

Question 8

The SUC2 gene in yeast encodes an enzyme to convert the sugar, sucrose, into glucose and fructose, which is necessary for yeast to use sucrose as a source of food. In the presence of glucose, SUC2 expression is switched off. But in the absence of glucose, SUC2 expression increases 100-fold. The expression of SUC2 in wild-type yeast and two mutant yeast strains is shown below. The mutations occur in two genes other than SUC2: SNF1 and SSN6. $$\begin{array} { | l | c c } 
\hline \text { Genotype } & { \text { SUC2 Expression } } \
\hline & + \text { glucose } & - \text { glucose } \
\hline \text { Wild type } & 1 & 100 \
\hline \text { snf1 } & < 1 & < 1 \
\hline \text { ssn } 6 & 100 & 100 \
\hline
\end{array}$$ a. Is the SNF1 gene normally important for activation or repression of SUC2 expression?
b. Is the SSN6 gene normally important for activation or repression of SUC2 expression?
c. If SNF1 and SSN6 work in the same pathway to regulate SUC2 expression, the order in which the genes acts can be one of two possibilities (where $\rightarrow$ indicates activation and $\perp$indicates inhibition): (1) SNF1 $\quad$ SSN6 $\quad$ SUC2
SSN6 acts to repress SUC2 expression, and SNF1 activates SUC2 by inhibiting the inhibitor, SSN6.
$\quad\quad\quad-\quad\quad\quad-$
(2) SSN6 $\quad$ SNF1 $\rightarrow$ SUC2
SNF1 activates $S U C 2$ expression, and SSN6 represses $S U C 2$ by inhibiting the action of SNF1. Design an experiment to distinguish between these two possible orders. What would you expect the outcome of your experiment to be in each of the two possible cases?

Accepted Answer

a. The SNF1 gene is normally important f

Question 9

A scientist has discovered a new gene that she believes encodes a transcriptional activator protein. She is trying to determine where this protein binds. Which of the following describes a technique she could use to answer her question?

Accepted Answer

A)  Chromatin immunoprecipitation to determine the DNA sequences to which the putative transcriptional activator protein binds 
B)  RNA interference to determine the RNA sequences to which the putative transcriptional activator protein binds 
C)  Crosslinking to determine the interactions the putative transcriptional activator protein has with other proteins 
D)  Chromative immunoprecipitation to determine the proteins to which the putative transcriptional activator protein binds 
E)  RNA interference combined with crosslinking to determine all DNA and RNA sequences to which the putative transcriptional activator protein binds 
A)  Chromatin immunoprecipitation to determine the DNA sequences to which the putative transcriptional activator protein binds 
B)  RNA interference to determine the RNA sequences to which the putative transcriptional activator protein binds 
C)  Crosslinking to determine the interactions the putative transcriptional activator protein has with other proteins 
D)  Chromative immunoprecipitation to determine the proteins to which the putative transcriptional activator protein binds 
E)  RNA interference combined with crosslinking to determine all DNA and RNA sequences to which the putative transcriptional activator protein binds

Question 10

What is the consequence of methylation of DNA sequences called CpG islands?

Accepted Answer

A)  active transcription 
B)  transcription repression 
C)  recruitment of chromosome-remodeling complex 
D)  transcriptional stalling 
E)  insulator sequence formation 
A)  active transcription 
B)  transcription repression 
C)  recruitment of chromosome-remodeling complex 
D)  transcriptional stalling 
E)  insulator sequence formation

Question 11

A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n):

Accepted Answer

A)  insulator. 
B)  silencer. 
C)  mediator. 
D)  enhancer. 
E)  repressor. 
A)  insulator. 
B)  silencer. 
C)  mediator. 
D)  enhancer. 
E)  repressor.

Question 12

Which of the following molecules is capable of targeting chromatin-remodeling complexes to specific DNA sequences to modify chromatin structure and activate gene expression?

Accepted Answer

A)  transcriptional repressor 
B)  enhancer 
C)  DNAse I 
D)  transcriptional activator 
E)  histone deacetylase 
A)  transcriptional repressor 
B)  enhancer 
C)  DNAse I 
D)  transcriptional activator 
E)  histone deacetylase

Question 13

Which gene-control mechanisms from the previous question are not used in prokaryotes, and why?

Accepted Answer

As the previous question is not provided

Question 14

Choose the CORRECT order of procedure in performing chromatin immunoprecipitation (ChIP). 1. DNA sequencing and fragment identification
2) Removal of crosslinking and separation of DNA and proteins
3) Crosslinking proteins and chromosomes via UV
4) Antibody incubation for immunoprecipitation
5) Protein degradation via proteases
6) Cell lysis and chromosome fragmentation

Accepted Answer

A)  1, 3, 2, 4, 5, 6 
B)  2, 6, 5, 1, 3, 4 
C)  4, 3, 2, 5, 1, 5 
D)  3, 6, 4, 2, 5, 1 
E)  5, 1, 3, 6, 4, 2 
A)  1, 3, 2, 4, 5, 6 
B)  2, 6, 5, 1, 3, 4 
C)  4, 3, 2, 5, 1, 5 
D)  3, 6, 4, 2, 5, 1 
E)  5, 1, 3, 6, 4, 2

Question 15

After translation, eukaryotic proteins can be modified by:

Accepted Answer

A)  acetylation. 
B)  the addition of phosphate groups. 
C)  the removal of amino acids. 
D)  the addition of methyl groups. 
E)  acetylation, addition of phosphate and methyl groups, or the removal of amino acids. 
A)  acetylation. 
B)  the addition of phosphate groups. 
C)  the removal of amino acids. 
D)  the addition of methyl groups. 
E)  acetylation, addition of phosphate and methyl groups, or the removal of amino acids.

Question 16

Which of the following statements about response elements is INCORRECT?

Accepted Answer

A)  A single eukaryotic gene is regulated by only one unique response element. 
B)  Response elements are composed of specific consensus sequences that are unique from one another. 
C)  Different genes can possess a common regulatory element upstream of their start site. 
D)  Multiple response elements allow the same gene to be activated by different stimuli. 
E)  Response elements allow complex biochemical responses in eukaryotic cells. 
A)  A single eukaryotic gene is regulated by only one unique response element. 
B)  Response elements are composed of specific consensus sequences that are unique from one another. 
C)  Different genes can possess a common regulatory element upstream of their start site. 
D)  Multiple response elements allow the same gene to be activated by different stimuli. 
E)  Response elements allow complex biochemical responses in eukaryotic cells.

Question 17

When siRNAs are present, the rate of mRNA degradation _____ and the rate of protein production _____.

Accepted Answer

A)  increases; increases 
B)  increases; decreases 
C)  decreases; decreases 
D)  decreases; increases 
E)  stays constant; decreases 
A)  increases; increases 
B)  increases; decreases 
C)  decreases; decreases 
D)  decreases; increases 
E)  stays constant; decreases

Question 18

What are two distinct functions that transcriptional activator proteins perform in order to regulate gene transcription?

Accepted Answer

Transcriptional activator proteins are c

Question 19

Insulators can block the effects of enhancers only when they lie:

Accepted Answer

A)  between an enhancer and a promoter. 
B)  upstream of a promoter. 
C)  adjacent to a promoter. 
D)  within the structural genes. 
E)  within a consensus sequence. 
A)  between an enhancer and a promoter. 
B)  upstream of a promoter. 
C)  adjacent to a promoter. 
D)  within the structural genes. 
E)  within a consensus sequence.

Question 20

Regulation of gene expression using siRNAs is found in:

Accepted Answer

A)  prokaryotes only. 
B)  eukaryotes only. 
C)  prokaryotes and eukaryotes. 
A)  prokaryotes only. 
B)  eukaryotes only. 
C)  prokaryotes and eukaryotes.

Exam 17: Control of Gene Expression in Eukaryotes

List five levels at which control of gene activity can take place in eukaryotes.

Explain how the poly(A)-binding protein that binds to the poly(A) tails located in the 3' end of an mRNA can play a key role in an mRNA degradation pathway that proceeds from the 5'end of an mRNA in a 5' →\rightarrow→ 3' direction.

Proteins that affect the structure of DNA bound to histones without altering histone chemical structure are called:

Define RNA silencing (or interference). Explain how siRNAs arise and how they potentially affect gene expression. How are siRNAs different from the antisense RNA mechanism?

If a deacetylase inhibitor were injected into a mouse brain, which of the following would you expect to occur?

Which type of control is illustrated by GAL4 in the control of genes for yeast galactose-metabolizing enzymes?

A scientist has discovered a new gene that she believes encodes a transcriptional activator protein. She is trying to determine where this protein binds. Which of the following describes a technique she could use to answer her question?

What is the consequence of methylation of DNA sequences called CpG islands?

A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n):

Which of the following molecules is capable of targeting chromatin-remodeling complexes to specific DNA sequences to modify chromatin structure and activate gene expression?

Which gene-control mechanisms from the previous question are not used in prokaryotes, and why?

After translation, eukaryotic proteins can be modified by:

Which of the following statements about response elements is INCORRECT?

When siRNAs are present, the rate of mRNA degradation _____ and the rate of protein production _____.

What are two distinct functions that transcriptional activator proteins perform in order to regulate gene transcription?

Insulators can block the effects of enhancers only when they lie:

Regulation of gene expression using siRNAs is found in:

Introduction to Genetics

Chromosomes and Cellular Reproduction

Basic Principles of Heredity

Sex Determination and Sex-Linked Characteristics

Extensions and Modifications of Basic Principles

Pedigree Analysis, Applications, and Genetic Testing

Linkage, Recombination, and Eukaryotic Gene Mapping

Chromosome Variation

Bacterial and Viral Genetic Systems

DNA: the Chemical Nature of the Gene

Chromosome Structure and Organelle Dna

DNA Replication and Recombination

Transcription

Rna Molecules and Rna Processing

The Genetic Code and Translation

Control of Gene Expression in Prokaryotes

Gene Mutations and Dna Repair

Molecular Genetic Analysis and Biotechnology

Genomics and Proteomics

Epigenetics

Developmental Genetics and Immunogenetics

Cancer Genetics

Quantitative Genetics

Population Genetics

Evolutionary Genetics

Filters

Explain how the poly(A)-binding protein that binds to the poly(A) tails located in the 3' end of an mRNA can play a key role in an mRNA degradation pathway that proceeds from the 5'end of an mRNA in a 5' $\rightarrow$ 3' direction.

When siRNAs are present, the rate of mRNA degradation _ and the rate of protein production _.