Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Transcription > Flashcards

Transcription Flashcards

1
Q

What is transcription?

A

Synthesis of RNA from DNA template

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

What is transcription catalyzed by?

A

RNA polymerase

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

How many subunits if RNA polymerase made of?

A

multiple (alpha, beta, beta prime, omega, sigma70)

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

What does transcription require?

A

A template:

  1. RNA strand synthesized is complimentary to the “template strand” of DNA
  2. The other DNA strand has the same sequence of the RNA strand w/ exception of the thymine (which is replaced with Uracil)
  3. Ribonucleoside Triphosphate (ATP, cTP, UTP, and GTP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What direction does transcription occur in?

A

5’ to 3’ direction

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

What is base +1?

A

First base that gets initiated/incorporated, initiates mRNA strand

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

What is upstream of transcriptional start site?

A

The promotor

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

What is the the promotor?

A

Where RNA polymerase binds

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

What recognizes the promotor?

A

alpha subunit to facilitate initiation

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

What components of the promotor?

A

-10 sequence, “pribnow box”
-35 sequence
(both on coding strand)

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

TATAAT

A

-10 Sequence, “pribnow box”

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

TTGAcA

A

-35 sequence

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

What happens after RNA polymerase binds to promotor?

A
  1. 17 bp segment of DNA unwinds
  2. Results in an open “promotor complex”
  3. RNA synthesis proceeds in 5’ to 3’ direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

RNA synthesis can start without a ________.

A

Primer

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

In bacteria, most newly synthesized RNA have ___ or ____.

A

pppG, pppA (1st nucleotide still with phosphate attached)

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

Name two methods that can terminate RNA synthesis

A
  1. Formation of an RNA hairpin from the transcribed gc-rich stop signal. On the mRNA transcript, a sequence of 4 or more uracils follow the hairpin.
  2. Rho (p) protein activity: Uses ATP to “catch up” to RNA polymerase complex and then dislodge it.
17
Q

What is the Lac Operon?

A

Model system to examine transcriptional regulation (when transcription is turned on and of)

18
Q

What are the three components of the Lac Operon?

A

x, y, z, i-gene

19
Q

What is X in the lac operon?

A

B-Galactosidase

20
Q

What is the purpose of B-Galactosidase?

A

Breaks the glycosidic linkage in lactose between galactose and glucose (disaccharide into two monosaccharides)

21
Q

What is Y in the lac operon?

A

Permease

22
Q

What is the purpose of Permease?

A

allows lactose into bacterial wall (B/c lactose is very polar, making it difficult to pass through on its own)

23
Q

What is Z in the lac operon?

A

Transacetylase

24
Q

What is the purpose of Transacetylase ?

A
  1. Assists with the metabolism of sugars

2. Transfers acetyl groups

25
Q

What is the i-gene in the lac operon?

A

Responsible for synthesis of repressor protein

26
Q

What is the repressor protein responsible?

A

tells us when transcription is turned on/off

27
Q

How does the repressor protein turn transcription off?

A

When it binds downstream to the 3’ end of the promotor (prevent RNA polymerase from binding to the promotor)

28
Q

What turns transcription back on?

A

1, 6-Allolactose (Variation of Lactose, which is usually a 1,4 linkage)

29
Q

How does 1, 6-Allolactose turn transcription on?

A

By binding to repressor protein to inhibit repressor protein from binding to promotor

30
Q

What is another way transcriptional regulation can occur in the lac operon?

A

Via glucose regulation

31
Q

______ prefer to utilize _________ before breaking down _________.

A

e. coli, glucose, lactose

32
Q

What binds to cyclic AMP to for cAMP-cap complexes?

A

catabolite activator protein

33
Q

What is the function of cAMP-cap complexes?

A

To help recruit RNA polymerase to the promotor?

34
Q

When glucose is _______, cAMP levels are low.

A

abundant

35
Q

When glucose levels are abundant, cAMP levels are ___.

A

low

36
Q

What happens when cAMP levels are low and there are few cAMP-cap complexes?

A

Lac operon has low levels of transcription

37
Q

When _____ is scarce, cAMP levels are high.

A

glucose

38
Q

When glucose is scarce, cAMP levels are ____.

A

high

39
Q

What happens when cAMP levels are high and there are many cAMP-cap complexes?

A

Lac operon has high levels of transcription

Biochemistry (15 decks)

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