Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Lecture 15 > Flashcards

Lecture 15 Flashcards

1
Q

What is produced during transcription?

A

A strand of messenger RNA (mRNA) is produced as a result of transcription.

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

What is the direction of transcription?

A

5’ to 3’

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

Why are molecular biologist always referring to the coding strand when they talk about a gene?

A

The non-template strand is referred to as the coding strand by the molecular biologist as it is the same as the RNA molecule produce except for the thymine bases.

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

What is the name of the protein that carries out DNA-directed RNA synthesis?

A

RNA polymerase

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

What molecules is chemically added to grow the mRNA? Which end is it added to? What molecule is released during the process?

A

NTP is added to grow mRNA. It is added to the 3’ end and releases two phosphate groups when it attaches to the mRNA.

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

What are the names of the two sequence that define the start of a gene in E. coli?

A

-35 and -10 sequence

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

What are the names of the three phases of transcription?

A

Initiation, Elongation and Termination

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

True or False: On a prokaryotic or eukaryotic chromosome there are genes on both strands of DNA.

A

TRUE

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

What are the roles of the three RNA polymerases in eukaryotes?

A

RNA Pol I - focus on rRNA, transcribes genes that encode rRNA, ribosomal RNA forms part of ribosome
RNA Pol II - produces the mRNA
RNA Pol III - transcribes that encode tRNA, one rRNA and other RNA

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

What is the main sequence that guides the RNA polymerase to the promoter?

A

TATA box

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

Where are the TATA box in the promoter sequences?

A

-30 region

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

True or False: RNA polymerase II is a large complex of many proteins.

A

TRUE

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

What is the difference between a general transcription factor and gene regulatory protein (transcription factor)?

A

General transcription factors are required for the expression of almost all genes whereas the gene regulatory proteins only regulate the expression of a subset of genes.

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

What is TBP and what is its role in transcription?

A

TBP is a TATA-binding protein that specifically recognises the TATA box.

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

What is TFIIB and what does it do?

A

It is a protein that binds to TBP and recruits Pol II-TFIIF complex. Bridge between pol II and TBP

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

What is TFIIH and what is its role?

A

It is a protein that unwinds RNA at promoter and phosphorylates Pol II wishing CTD. Also recruits nucleotide-excision repair proteins.

17
Q

What modification occurs to the CTD of RNA Pol II, and what does this achieve?

A

The CTD is phosphorylated by TFIIH which changes the conformation of Pol II that allows it to begin elongation.

18
Q

What do terminating factors achieve?

A

Terminating factors facilitate in the dephosphorylation of CTD.

19
Q

What three types of processing occur to the initial transcript to make a mature mRNA?

A

The addition of a 5’ cap and poly A tail as well as the cleavage and splicing of introns.

20
Q

What is added the 5’ end on an mRNA? What is this for?

A

7-methylguanosine is added to the 5’ end to prevent it from undergoing degradation due to instability.

21
Q

True or False: 7-methylguanosine is added to the 5’ end of an mRNA with a phosphodiester bond.

A

TRUE

22
Q

What does the spliceosome do? Where in the pre-mRNA are the sequences located that are recognised by this complex? What parts off the complex are binding to these sequences?

A

The spliceosome splices out the introns.

23
Q

True or False: The process of splicing regularly introduces small variation between each mRNA.

A

TRUE?

24
Q

True or False: The spliceosome contains both protein and RNAs.

A

TRUE

25
Q

True or False: There is a sequence at the end of the mRNA that signals for a polyA tail to be added, but this is not present in the original gene has been added by the RNA polymerase.

A

FALSE: There is a sequence in the original gene the transcribed onto mRNA as AAUAA which is read by the polyadenylation factors that trim off excess RNA sequences after this sequence and adds the polyA tail.

26
Q

How does the TATA box show which directionality?

A

The TATA box is a sequence (TATAAA) that has directionality because of the extra As on the end which on the complementary strand would be ATATTT

27
Q

RNA polymerase II

A

Responsible for the expression of most genes. It is a large and complex molecule that has 12 subunits- allows it more regulation of gene expression, allows for interaction between different proteins.

28
Q

What happens during initiation of transcription?

A

TBP binds to TATA box sequence, TFIIB binds to TBP and recruits Pol II and TFIIF. Then TFIIH binds to Pol II.
TFIIH phosphorylates CTD (C terminal domain) which changes conformation of Pol II.

29
Q

Termination of transcription

A

Termination factors

- phosphates removed.

Biochemistry (12 decks)

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