Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 335 Genetics > Exam 3 Prep > Flashcards

Exam 3 Prep Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Genetic regulatory proteins bind to the DNA.

A

Transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Repressor proteins bind to an mRNA and prevent ribosome binding.

A

Translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A transcription terminator forms in the RNA.

A

Transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Riboswitches produce an RNA conformation that prevents ribosome binding.

A

Translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Antisense RNA binds to the mRNA.

A

translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The product of a metabolic pathway inhibits the first enzyme in a pathway.

A

Post-translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A protein is covalently modified.

A

Post-translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which gene is responsible for producing the protein that converts lactose to allolactose?

A

lacZ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which of the following would NOT be considered a reversible post-translational modification?

Proteolytic processing
Acetylation
Methylation
Phosphorylation

A

Proteolytic processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The trpR gene encodes a _____.

A

Repressor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The trp repressor is bound to the operator when tryptophan levels are _____.

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The trp operon is also regulated by _____ attenuation.

A

transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Attenuation is similar to rho _____ termination.

A

independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The mRNA from the trpL gene forms stem loops as it is being _____.

A

transcribed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

An inducer binds to an activator protein and inhibits transcription. True or False

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can antisense RNA inhibit translation?

A

An antisense RNA binds to a transcript and inhibits translation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

An inhibitor regulates an inducible gene. True or False

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T/F The lacI gene makes a repressor protein.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

T/F The structural proteins encoded by the lac operon are involved in lactose synthesis.

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

T/F The CAP protein is an activator that binds to the operator.

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

T/F The product of lacI is an allosteric protein that can undergo a conformational change when allolactose binds to it.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T/F CAP binding causes the DNA to bend facilitating RNA polymerase binding.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which of the following sets of conditions would result in high levels of gene transcription from the lac operon?

Low glucose, low lactose
High glucose, high lactose
Low glucose, high lactose
High glucose, low lactose
A

Low glucose, high lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

You identify a CAP mutant protein that is constituitively bound to the CAP site.

Under which conditions will the lac operon be transcribed at high levels in cells that contain this mutant protein?

Lactose is present, glucose is not 
Neither lactose nor glucose is present 
Lactose and glucose are both present 
Glucose is present, lactose is not
A

Lactose is present, glucose is not

Lactose and glucose are both present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

If a cell has a mutation in the lacY gene that produces a non-functional product, how is regulation of the lac operon affected?
Multiple Choice

Expression of the lac operon is normal because lacY is not required to produce allolactose.
The lac repressor cannot bind to the operator.
The lac operon cannot be induced, because lactose cannot enter the cell.
The lac operon cannot be transcribed by RNA polymerase because of the lacY mutation.
A

The lac operon cannot be induced, because lactose cannot enter the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How is the lac operon regulated?
Multiple Choice

It is inducible, under positive control.

It is repressible, under negative and positive control.

It is repressible, under negative control.

It is inducible, under negative and positive control
A

It is inducible, under negative and positive control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The absence of lactose results in the lac repressor protein _________blank.
Multiple Choice

binding both the DNA and allolactose

binding to DNA

binding to other lac repressors

binding to allolactose
A

binding to DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Transcription of the lac operon results in the production of how many different mRNA transcripts?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Attenuation of the trp operon requires which conditions to be met?
Multiple Choice

Tryptophan levels must be low and regions 3 and 4 must pair.
Tryptophan levels must be high and regions 2 and 3 must pair.

Tryptophan levels must be high, and regions 3 and 4 must pair.
Tryptophan levels must be low and regions 2 and 3 must pair.
A

Tryptophan levels must be high, and regions 3 and 4 must pair.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Translation of mRNA transcribed from the trp operon can be regulated by formation of a secondary structure within the mRNA.

The mRNA that forms this secondary structure is transcribed from which gene in the trp operon?
Multiple Choice

operator

trpE

trpA

trpL
A

trpL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

The presence of a small effector molecule may inhibit transcription. True or False

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

You identify a CAP protein mutant that is unable to bind cAMP.

How will this mutant affect transcription of the lac operon?
Multiple Choice

The lac operon will always be transcribed at a high rate.
The lac operon will only be transcribed at a high rate when lactose is present and glucose is not.
The lac operon will only be transcribed at a high rate when glucose is present and lactose is not.
The lac operon will never be transcribed at a high rate.
A

The lac operon will never be transcribed at a high rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

One form of gene expression control found frequently in prokaryotes involves a _____, which occurs when an RNA can exist in two different secondary conformations.

A

riboswitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

One conformation of the RNA requires a small molecule binding which stabilizes the _____ structure.

A

secondary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

In Bacillus subtilis, a riboswitch controls the _____ of the thi operon involved in thiamin pyrophosphate synthesis.

A

transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Riboswitches can regulate transcription, _____, and RNA stability.

A

translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Bacteria use riboswitches extensively; about _____ of bacterial genes are regulated this way.

A

4%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

T/F DNA binding proteins involved in the regulation of gene expression bind covalently and irreversibly to specific DNA sequences.

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Which of the following interact with DNA in a non-sequence specific manner?

Histones
Sigma factors
both

A

Histones

40
Q

T/F Two genes in a bacterial cell may be expressed at different levels, but each individual gene is expressed at the same level under all environmental conditions.

A

F

41
Q

A

A

Regulatory Gene

42
Q

B

A

Lac promoter (lac P)

43
Q

C

A

LacZ

44
Q

D

A

LacY

45
Q

E

A

LacA

46
Q

F

A

I promoter

47
Q

G

A

CAP site

48
Q

H

A

Operator site (lac O)

49
Q

The selection of which chromosome is inactivated is a _____ process.

A

random

50
Q

The inactive X chromosome in a human female somatic cell is called a _____.

A

barr body

51
Q

Although the Tsix transcript is produced by both X chromosomes the Xist transcript is only produced from the _____ chromosome.

A

inactive

52
Q

The symmetry break that occurs is due to localization of _____ to one X chromosome.

A

CTCFs

53
Q

Presence of the Xist transcript on the Xi chromosome results in the recruitment of _____.

A

macro H2A

54
Q

At least some genes are silenced on inactive X chromosomes by _____.

A

methylation

55
Q

Select the functional roles of heterochromatin.
Check All That Apply

Gene silencing Gene silencing
Preventing transposition Preventing transposition
Preventing viral proliferation Preventing viral proliferation
Preventing X-inactivation
A

Gene silencing Gene silencing
Preventing transposition Preventing transposition
Preventing viral proliferation Preventing viral proliferation

56
Q

What is a property of a bidirectional enhancer?
Multiple Choice

It can enhance transcription independently of its orientation to the gene.
It binds directly to mediator proteins.
It is located in the core promoter.
It is bound by TFIID.
A

It can enhance transcription independently of its orientation to the gene

57
Q

A transcriptional repressor that controls the transcription of gene A is not normally active unless bound by an effector molecule X. In a certain cell, the domain of the repressor that binds X is mutated so that X can no longer be bound.

With all other factors being the same, what effect do you predict on the transcription of gene A if X is added to the cell when it is already transcribing gene A?

A

The transcription of gene A will not be affected

58
Q

T/F Maintenance methylation of DNA is rare and highly regulated.

A

F

59
Q

If a drug was developed that could inhibit TFIID binding to the core promoter, what would its effect on transcription be?

A

Transcription that was currently occurring would be finished but there would be no new initiation.

60
Q

T/F DNA methylation in eukaryotes, which is associated with transcription inhibition, occurs on A residues at GATC sites.

A

F

61
Q

The inheritance of traits is sometimes the direct result of specific alleles being present or absent, but it can also be due to the ability of an allele to be _____.

A

Expressed

62
Q

The definition of epigenetics is the study of mechanisms of heritable traits that _____ the result of changes in DNA sequence.

A

are not

63
Q

In _____ inheritance the transmission of the trait may be based not on the allele but on which parent the allele comes from.

A

epigenetic

64
Q

The modifications made to DNA in epigenetics results in changes in _____ association with the DNA.

A

protein

65
Q

In epigenetics, change can be due to _____ of DNA.

A

methylation

66
Q

Which of the following bonds would mediate the interaction between a regulatory DNA binding protein and the double-stranded DNA?

Non-covalent bonds
Covalent bonds
Both

A

Non-Covalent bonds

67
Q

Which of the following is TRUE of alternative sigma factors in E. Coli?

A) Alternative sigma factors bind to promoters with a different -35 sequence element than the main sigma factor (sigma 70)
B) Alternative sigma factors regulate the expression of genes under specific environmental conditions or stresses
C) Alternative sigma factors are always abundant in the cell and bind to the sigma 70 promoter with high affinity.
D) A and B
E) B and C

A

D

68
Q

Which of the following sequences does a bacterial depressor bind to ?

Promoter
Operator
Activator
Terminator

A

Operator

69
Q

T/F Genes controlled by an activator protein typically have a promoter sequence that has a weak affinity for binding sigma factors.

A

T

70
Q

T/F In bacteria, small effector molecules control whether or not repressors and activators bind to DNA

A

T

71
Q

When considering gene regulation in bacteria which of the following is TRUE of inducible genes:

A) An inducer will bind to a repressor putting it in a conformation that can bind to the operator
B) Inducible genes are typically involved in catabolic pathways
C) Inducibe genes are only under negative controle
D) A and B
E) B and C

A

B

72
Q

If a bacteria gene is regulated by both positive and negative controle which of the following sites would you find the DNA?

A0 Operator site
B) Activator site
C) Effector site
D) A and B
E) A, B, and C

A

D

73
Q

In the lac operon consists of three genes: lacZ, lacY, and lac A. How many promoters are required to express these three genes?

A

1

74
Q

Which of the following is TRUE of the lac operon when lactose is present?

A) Lactose is converted to allolactose by beta-galactosidase
B) Allolactoswe binds to the repressor protein
C) The repressor protein is in a conformation that binds to the operon
D) A and B
E) A, B, and C

A

D

75
Q

Which of the following is true of the positive control when considering the regulation of the lac operon?

A) Adenylyl cyclase is inhibited by glucose
B) If cAMP levels are high the CAP protein will bind to the CAP site in the DNA
C) CAP protein binding to the CAP site in the DNA stabilizes the RNA polymerase at the promotoer
D) A and B
E) A, B, and C

A

E

76
Q

Considering the regulation of the lac operon in E. coli which of the following is true when the cell is in the presence of both glucos and lactose?

A) The repressor is not bound to the operator in the DNA
B) CAP is not bound to the CAP site in the DNA
C) There is a high level of transcription of lacZYA
D) A and B
E) A, B, and C

A

D

77
Q

Consider and E. coli cell with not lactose present, How many beta-galactosidase molecules are in this E. coli cell?

None
a little
a lot

A

a little

78
Q

T/F The trp operon is a repressible operon regulated by both negative and positive controle

A

F

79
Q

Which of the following is true when there is an excessive amount of tyrptophan present in the cell?

A) Charged tRNA serves as the corepressor and binds to the repressor protein
B) Free tryptophan serves as the corepressor and binds to the repressor protein
C) The repressor is bound to the corepressor, putting it in a conformation that does NOT bind to the operator
D) A and C
E) B and C

A

B

80
Q

What is the purpose of the attenuation mechanism for regulation the trp operon?

A

To sense the amount of tRNA charged with tryptophan in the cell

81
Q

Which of the following is involved in the attenuation mechanism in the regulation of the trp operon?

A) A leader region in the mRNA containing codons for Tryptophan
B) Anintrinsic termination signal
C) Coupled transcription-translation
D) A and B
E) A, B, and C

A

E

82
Q

Consider the regulation of the trp operon. Which of the following is true when there is not tryptophan present and coupled transcrition-translation is occurring?

A) The repressor is not bound to the operator
B) The ribosome stalls at the Trp-Trp codons in the mRNA molecule
C) An intrinsic termination signal forms in the mRNA
D) A and B
E) A, B, and C

A

D

83
Q

Which of the following is a mechanism for modulation the activity of eukaryotic transcription factors?

A) Binding of small molecules
B) Formation of homodimers
C) Covalent modification
E) All of the above

A

E

84
Q

What type of genes are constitutive genes?

A

Genes that are expressed continuously in all cells of an organism, regardless of environmental conditions or the cell’s stage in the cell cycle.

85
Q

What type of genes are regulated?

A

Specific metabolic pathways

86
Q

What would be the most efficient way to regulate a bacterial gene?

A

Regulate transcription, translation, and post translation

87
Q

Which of the following is true with regards to enhancer sequences?

A) They are orientation-dependent
B) They may be located either upstream or downstream of the promoter
C) Repressor proteins bind to them
D) They cannot be downstream of the start of transcription

A

B) They may be located either upstream or downstream of the promoter

88
Q

What can increase transcription?

A

Acetylation of histone
Recruitment of SWI/SNF complex
Decreased methylation of DNA
Creation of an NFR

89
Q

What can decrease transcription?

A

Removal of core promoter
Increased methylation of DNA
Increased nucleosome density

90
Q

What are some characteristics of heterochromation?

A

Stained throughout the entire cell cycle
Attached to nuclear lamina
Inhibits gee expression
More compacted

91
Q

What are some characteristics of euchromatin?

A

Not stained during interphase
Central position in the nucleus
Promotes gene expression
Less compacted

92
Q

Consider the regulation of the lac operon in E. coli. Which of the following is TRUE when the cell is in the presence of glucose but no lactose?

A) the repressor protein is not bound to the operator
B) CAP is not bound to the CAP site in the DNA
C) Adenylyl Cyclase is active
D) The operon is transcribed at high levels
E) All of the above

A

B) CAP is not bound to the CAP site in the DNA

93
Q

Consider the regulation of the trp operon in E.coli. Transcription of the leader region has occurred, but there is no translation. Which of the following if TRUE?

A) The RNA polymerase will continue transcribing the operon
B) The repressor protein will block the RNA polymerase after the leader region
C) Region 1 of the leader region pairs with region 2 and region 3 pairs with region 4
D) Region 2 of the leader region pairs with region 3

A

C) Region 1 of the leader region pairs with region 2 and region 3 pairs with region 4

94
Q

Which of the following is TRUE of DNA methylation in eukaryotes?

A) DNA methylation occurs at CpG
B) Methylation typically inhibits transcription by inhibiting initiation of transcription
C) de novo methylation is highly regulated
D) A and B
E) A, B and C

A

E) A, B and C

95
Q

Which of the following is TRUE of epigenetic changes in gene expression?

A) Epigenetic changes can be heritable, meaning these changes can be passed to daughter cells following cell division
B) Epigenetic changes may involve changes in chromatin structure
C) Epigenetic changes result in a change in the DNA sequence
D) A and B
E) A, B and C

A

D) A and B

96
Q

The maltose operon contains three genes: malE, malF, and malG. Transcription of this operon would result in ___ mRNA transcript(s) which encodes ___ stop codon(s).

A

1:3

Chapter 14
Slides 21-30

97
Q
A

BIO 335 Genetics (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions