Brainscape's Knowledge GenomeTM

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


See full index

Biology > Gene Transcription & RNA modification part 3 > Flashcards

Gene Transcription & RNA modification part 3 Flashcards

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

What are the 3 types of proteins needed for basal transcription at the core promoter?

A
  1. RNA polymerase 2
  2. General transcription factors (5 GTF)
  3. Mediator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Basal transcription

A

Baseline expression which has many genes & doesn’t have regulatory proteins

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

_____ are always need for RNA polymerase 2 to initiate transcription of genes

A

5 GTF

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

Describe the first 3 steps to form a open complex & start transcription?

A
  1. TFIID binds to TATA box
  2. TFIIB binds to TFIID
  3. TFIIB binds TFIIF & RNA polymerase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the last 3 steps to form a open complex & start transcription?

A
  1. TFIIE & TFIIH bind to RNA polymerase 2 to form a preinitiation complex (closed complex)(PIC)
  2. TFIIH acts as a helicase to form an open complex by unwinding the DNA & it also acts as as kinase
  3. TFIIB, TFIIE, & TFIIH released to form an open complex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Kinase

A

Adds phosphate & it then phosphorylates the tail of RNA polymerase 2

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

TFIID

A

Is a complex of proteins that includes the TATA binding protein (TBP) & severally TBP associated factors (TAFs)

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

Mediator

A

Medicates interactions between RNA polymerase 2 & regulatory transcription factors that bind to enhancers or silencers

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

Transcriptional termination of __________ occurs after the 3’ end of the transcript is cleaved near the polyadenylation signal sequence

A

RNA polymerase

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

What are the 2 models in termination

A
  1. Allosteric Model

2. Torpedo Model

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

Allosteric Model

A

After transcribing the polyadenylation signal sequence, RNA polymerase 2 is destabilized & falls off from the DNA (cause a change in its shape)

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

Torpedo Model

A

An exonuclease binds to the 5’ end of the RNA that is still transcribed & degrades it in the 5’ to 3’ direction & polymerase falls off

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

Describe termination process

A
  1. RNA polymerase 2 transcribed a gene past the polyadenylation signal sequence
  2. The RNA is cleaved just past the polyadenylation signal sequence
  3. Either the allosteric model is occurs or the torpedo model occurs to end termination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

___________ occurs after transcription where rRNA remove spacers, tRNA adds CCA & mRNA cap, spliced, & polyadenylated

A

RNA modifications

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

________ formed in the nucleolus & it is transcribed, processed & bound to ribosomes where its modification makes mRNA short

A

rRNA

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

Exon

A

Contain coding sequences that are translated into proteins & found in mature mRNA

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

Introns

A

Found between exons & contain coding sequences that aren’t translated into proteins

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

What happens with tRNA?

A

Makes mRNA go from long to short where both ends are digested, CCA to 3’ end & modifies nucleotides

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

The production of tRNA molecules require what two things?

A
  1. Exonuclease

2. Endonuclease

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

Exonuclease (RNaseD)

A

Cleaves a covalent bond between two nucleotides at one end of a strand & digest a strand

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

Endonuclease (RNaseP)

A

Cleaves the bond between two adjacent nucleotides within a strand

22
Q

What are the modified bases in tRNA?

A
  1. mG=methylguanosine
  2. P=pseudourine
  3. T= 4 - throuridine
  4. IP= 2-Isopentenyladensosine
23
Q

Ribozyme

A

An RNA with catalytic activity (ex. RNaseP)

24
Q

_______ is modified in the nucleus, spliced, capped, at the 5’ end, & poly-A at the 3’ end

A

mRNA

25
Q

Prokaryotes has a _________

A

Co-linear info - same info from gene to protein (Eukaryotes are not always co-linear)

26
Q

During transcription _______ contains introns & exons where the introns are removed & exons are connected to make a mature mRNA

A

pre-mRNA

27
Q

________ removes all introns & some exons & links exons by phosphodiester bonds)

A

Splicing

28
Q

What are the 3 mechanisms of splicing ?

A
  1. Group 1
  2. Group 2
  3. Spliceosome
29
Q

______ & ______ occur via self splicing where the splicing doesn’t need the addition of a catalyst instead the mRNA features as its own ribozyme (catalyst)

A

Group 1 & Group 2

30
Q

Describe group 1 splicing

A
  1. The guanosine break the bond bewteen the 1st exon & the intron where it becomes attached to the 5’ end of the intron
  2. The 3’- OH group of exon 1 then breaks the bond next to a different nucleotide that lies at the boundary between the end of the intron & exon 1 forms a phosphodiester bond with the 5’ end of exon 2
  3. The intron RNA is degraded
31
Q

Maturases

A

Proteins that enhance the rate of self-splicing

32
Q

pre-mRNA splicing occurs by __________

A

Spliceosome

33
Q

Spliceosome

A

A large complex that spliced pre-mRNA in eukaryotes & contain several subunits call small riboproteins (snRNPs)(“snurps”)(Contaisn RNA & proteins)

34
Q

Describe the splicing process

A
  1. The snRNPs designated U1 binds to the 5’ splice site & U2 binds to the branch site
  2. U4/U6 & U5trimer binds. The intron loops out & exons are brought closer together
  3. 5’ splice site is cut (1st splice site) & the 5’ end of intron is connected to the branch site to form a lariat where U1 & U4 are released
  4. 3’ splice site is cut (2nd splice site). Exon 1 is connected to exon 2 & the intron is released along with U2, U5, & U6. The intron will be degraded
  5. End up having two connected exons
35
Q

_________ binds intron-exon boundary & correct orientation by catalyze reaction

A

Spliceosome

36
Q

__________ regulates which exons occur in an RNA transcript, allowing different polypeptides to be made from the same protein-encoding gene

A

Alternative Splicing

37
Q

Alernative Splicing

A

Phenomenon that pre-mRNA can be spliced in more than one way

38
Q

What is an advatange of alternative splicing?

A

Since it allows two or more different polypeptides sequences to be derived from a single gene it can allow organisms to carry fewer genes it its genome

39
Q

The ends of eukaryotic pre-mRNA have a ________ & ________

A

5’ cap & 3’ polyA tail

40
Q

At their 5’ end most mature mature mRNA have a __________ covalently attached through capping

A

7-methylguanosine

41
Q

_________ adds methylguanosine

A

Capping

42
Q

Describe the process of capping

A
  1. Nucleotide at the 5’ end of the transcript has phosphate groups
  2. Guanyltransferase uses guanosine triphosphate (GTP) to attach a guanosine monophosphate (GMP) to the 5’ end
  3. Finally a methyltransferase attached a methyl group to the base guanine
43
Q

Describe the 5’ Cap function

A
  1. Cap-binding proteins are requires for the proper exist of most mRNA from the nucleous
  2. The cap structure is recognized by initation factors that are needed during the early stages of translation
  3. The cap structure is needed in efficient splicing of intron (closes to the 5’ end)
44
Q

At the 3’ end most mature mRNA have a string of adenine nucleotides called ______ which is important for mRNA stability, the exit out of the nucleus, & in synthesis of polypeptides

A

Poly A tail

45
Q

A poly A tail is added to mature mRNA through __________

A

Polyadenylation

46
Q

Describe polyadenlylation process

A
  1. The pre-mRNA contains a polyadenylation signal sequence near its 3’ end (usually AAUAAA)
  2. Anednoclease recognize the signal sequence & cleaves the pre-mRNA at a location 20 nucleotides before the 3’ end
  3. Poly-A polymerase enzyme attaches many adenine containing nucleotides
47
Q

The nucleotide sequence of RNA can be modified by _________

A

RNA editing

48
Q

RNA editing

A

Process of making a change in the nucleotide sequence of an RNA molecule that involves addition or deletions of particular nucleotides or substitution

49
Q

Describe RNA editing by deamination

A
  1. A cytidine deaminase can remove an amino group from cytosine thereby creating uracil
  2. An adenosine deaminase can remove an amino group from adenine to make hypoxanthine ( I = G in translation)
50
Q

_______ is important because it changes mRNA sequence which changed protein sequence which changes the way protein functions

A

mRNA editing

Biology (64 decks)

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