Brainscape's Knowledge GenomeTM

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


See full index

College Biology > Lecture 12 > Flashcards

Lecture 12 Flashcards

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

What is controlling gene expression?

A

when you control the production of a protein.

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

What is a way to control gene expression?

A

By controlling transcription initiation.

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

What is a way to control transcription initiation?

A

A regulatory proteins binding to DNA, which blocks or stimulates transcription.

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

How is gene expression controlled in prokaryotes?

A

Through control of transcription initiation.

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

What is positive control?

A

When the frequency of initiation of a transcript increases.

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

What does positive control do?

A

Activators enhance binding of RNA polymerase to promoter.

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

What is negative control?

A

When the frequency of initiation of a transcript decreases.

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

What does negative control do?

A

Repressors bind to operators in DNA.

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

How do prokaryotic cells often respond to their environment?

A

By changes in the gene expression.

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

What is an operon?

A

Blocks of genes controlled together. They are transcribed together on 1 mRNA and under the same regulation.

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

Where are operons used?

A

In bacteria and prokaryotes.

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

What are inducible operons?

A

When the transcription is usually off and needs to be turned on. (light switch down)

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

What are repressible operons?

A

When the transcription is usually on and needs to be turned off. (light switch up)

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

What are parts of an operon?

A
  1. Promoter
  2. Operator
  3. Regulator
  4. Genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does a promoter do?

A

It recruits the RNA polymerase for transcription.

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

What does an operator do?

A

It controls whether transcription occurs, by either blocking or not the progress of the RNA polymerase.

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

What does a regulator do?

A

It is a protein that alters the state of the operon. Either for or against transcription.

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

What does a gene do?

A

It is the sequence that is transcribed to make proteins.

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

What is a lac operon?

A

An operon that contains genes for the use of lactose as an energy source.

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

What are 3 types of lac operons?

A
  1. lacZ
  2. lacY
  3. lacA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Is the lac operon inducible or repressible?

A

Inducible.

22
Q

What is the lac operon negatively regulated by?

A

A repressor protein.

23
Q

How is the lac operon negatively regulated by a repressor protein?

A

The lac repressor binds to the operator to block the transcription.

24
Q

How is the lac operon activated?

A

In the presence of lactose, an inducer molecule binds to the repressor protein, so the repressor can no longer bind to the operator and transcription proceeds.

25
Q

What energy is easier to use than lactose?

A

Glucose.

26
Q

What is the preferred sugar to use?

A

Glucose, then lactose.

27
Q

How is glucose repressed?

A

An activator protein stimulates transcription. Catabolic activator protein (CAP) is an allosteric protein with cAMP as effector. The level of cAMP in cells is reduced in the presence of glucose so that no stimulation of transcription from CAP responsive operons takes place.

28
Q

What is inducer exclusion?

A

When the presence of glucose inhibits the transport of lactose into the cell.

29
Q

What is trp operon?

A

The genes for the biosynthesis of tryptophan.

30
Q

When is the trp operon not expressed?

A

When the cell contains sufficient amounts of tryptophan.

31
Q

When is the trp operon expressed?

A

When levels of tryptophan are low.

32
Q

Is the trp operon repressible or inducible?

A

Repressible.

33
Q

How is the trp operon negatively regulated by the trp repressor protein?

A

The trp repressor binds to the operator to block transcription. The binding of the repressor to the operator requires a corepressor which is tryptophan. When tryptophan levels fall, the repressor cannot bind to the operator.

34
Q

What are major differences of gene expression control in prokaryotes and eukaryotes?

A
  1. Eukaryotes have DNA organized into chromatin, which complicates protein-DNA interaction
  2. Eukaryotic transcription occurs in the nucleus.
  3. The amount of DNA regulating eukaryotic genes is much larger
35
Q

What are transcription factors and regulators?

A

Proteins that regulate transcription. They can be activators or repressors.

36
Q

What are general transcription factors?

A

The regular machinery of transcription.

37
Q

What is a specific transcription factor?

A

An act in a tissue or time dependant manner to stimulate higher or lower levels than the basal level.

38
Q

What are specifice transcription factors made of?

A

A DNA-binding domain and a separate activating or repressing domain that interacts with the transcription apparatus.

39
Q

What are types of transcription factors/regulators?

A
  1. Transcriptional activator proteins
  2. Coactivators
  3. Transcriptional repressor proteins
  4. Corepressors
40
Q

What is transcriptional activator proteins?

A

They activate and bind DNA.

41
Q

What are coactivators?

A

They activate and bind activators.

42
Q

What are transcriptional repressor proteins?

A

They repress and bind DNA.

43
Q

What are corepressors?

A

They repress and bind repressors.

44
Q

What is a promoter?

A

A sequence that binds the RNA polymerase.

45
Q

What is an enhancer?

A

A sequence that activators bind.

46
Q

What are silencers?

A

A sequence that repressors bind.

47
Q

What are insulators?

A

A sequence that divides genes, boundary element, prevents activators, and repressors from affecting genes they are not intended to.

48
Q

Where are the promoters found?

A

Basal promoters have a defined position, but the rest can be in a 5’ gene, a 3’ gene, or in an intron.

49
Q

What are regulation processes within the DNA level?

A
  1. Chromatin structure
  2. Euchromatin v. heterochromatin
  3. histone modifications
  4. DNA methylation
50
Q

what are regulation processes within the RNA level?

A
  1. Alternative splicing
  2. RNA degradation
  3. mRNA
  4. siRNA
  5. RNA editing
51
Q

What are regulation processes within the protein level?

A
  1. Protein stability
  2. miRNA
52
Q
A

College Biology (24 decks)

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