Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIOL 0280 UNIT 4 > Lecture 20: Transcription & RNA Metabolism > Flashcards

Lecture 20: Transcription & RNA Metabolism Flashcards

(75 cards)

Start Studying
1
Q

Intro Facts

Where does Transcription and Translation occur in prokaryotic cells?

Eukaryotic cells?

A

Prokaryotic - everything occurs in the cytoplasm

Eukaryotic
- Transcription & Processing/Transportation
= Nucleus

  • Translation = in the Cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Intro Facts

What is transcription?

What is the purpose of transcription?

A
  • Transcription is the process of copying a segment of DNA into RNA
  • The purpose of transcription is to make RNA copies of genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Intro Facts

How many DNA serve as a template in transcription?

A

Only one DNA will serve as a template

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

Intro facts

What is the template strand?

What is the non template/coding strand?

A

Template: The strand that is complimentary to RNA transcript

Non template: the same sequence as RNA (with T instead of U)

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

Transcription vs. DNA replication

How much of the genome is copied in Transcription vs. DNA replication?

A

Transcription: One/particular group of genes

DNA replication: whole genome

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

Transcription vs. DNA replication

What is the template used in Transcription vs. DNA replication?

A

Transcription: only one strand serves as the template

DNA replication: both strands will serve as template

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

Transcription vs. DNA replication

Which processes use primers?

A

Transcription does not use primers

DNA replication uses primers

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

Transcription Basics

Are polymers built continuously?

A

Yes, polymers are built continuously (processive)

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

Transcription Basics

In what direction is RNA synthesized?

Describe the relationship between the template and RNA strand

A

5’ -> 3’

  • They are anti-parallell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Transcription Basics

What is RNA Polymerase?

A

Enzymes that catalyzes the synthesis of RNA by reading the template strand

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

Transcription Basics

Does RNA polymerase require a primer?

What does RNA polymerase use?

A
  • Does not require a primer
  • Uses ribonucleotides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Essential Components of a Gene

What are the 4 essential components of a gene?

A

1) Promoter
2) Transcription factors
3) RNA Polymerase
4) Terminator

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

Essential Components of a Gene

What is the promotor region?

A

Sequence of DNA where transcription proteins assemble

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

Essential Components of a Gene

What specific machinery do we need at the promoter?

A
  • Transcription factors
  • RNA Polymerase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Essential Components of a Gene

What do transcription factors do?

A

They are proteins that bind to promoters to direct RNA synthesis

MAIN PURPOSE: Increase affinity of RNA polymerase at the promoter region

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

Essential Components of a Gene

What is the terminator region?

A

Sequence of DNA where transcription ends

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

Transcription Phases

What are the 4 phases of transcription?

What is its nemonic?

A

1) Assemble
2) Initiation
3) Elongation
4) Termination

Aliens Invade Earth Tonight

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

Transcription Phases

Which phases of transcription are very different in prokaryotes vs. eukaryotes?

A

Initiation & termination

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

Transcription Phases

What are transcription factors typically referred to as in prokaryotes?

A

Sigma factors

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

Transcription Phases

What are sigma factors?

A

Proteins that bind to specific DNA sequences in the promoter and increase affinity for RNA polymerase

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

Transcription Phases

What are consensus sequences?

A

DNA sequences that transcription factors and polymerases repeatedly assemble at

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

Transcription Phases

Where do transcription factors, sigma factors, and polymerases assemble?

A

They assemble at the promoter

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

Transcription Phases

What are the steps of initiation?

A

1) Initiation occurs at the promotor sequence

2) Transcription factors, sigma 70 & RNAPs assemble at the promoter region and forms a closed complex

3) Transcription bubble forms and RNAP forms open complex

4) Transcription is initiated

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

Transcription Phases

What are the main things that occur during elongation?

What are the steps of elongation?

A

Main Occurrences
- Clearing the promoter
- RNA polymerase builds the RNA strand by complementing the template strand

Steps
1) Sigma 70 disassociates
2) Sigma 70 is replaced by NusA
3) Transcription terminates and NusA disassociates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
*Transcription Phases* Super coils form during the elongation process In what direction do they form? What kind form?
Positive supercoils in the direction of transcription Negative supercoils in the opposite direction of transcription
26
*Transcription Phases* What is the cost of putting in a new nucleotide during elongation?
2 ATP equivalents
27
*Transcription Phases* What is the main thing that occurs during termination?
RNA polymerase dissociates from DNA strand, releasing newly synthesized RNA polymer
28
*Transcription Phases* What are the two different termination methods that occur in prokaryotes
- ρ-independent - ρ-dependent
29
*Transcription Phases* Describe the difference between ρ-independent and ρ-dependent
ρ-independent - relies on a repeating palindromic sequences at the termination sequence - RNA transcribed from these sequences fold onto itself ρ-dependent - relies on ρ helicase, a hexamer protein that binds to the rut element and travels fowards, disassociating the elongation machinery
30
*Eukaryotic vs. Prokaryotic Transcription* What are the 3 key differences between the two transcription methods?
1) There are many MORE transcription factors called general transcription factors in assembly, not one signal sigma factor - However their job is still to increase affinity of promoter to RNA polymerase 2) C-terminal Domain (CTD) on RNA polymerase is phosphorylated to start elongation 3) In the same vein, elongation is terminated by dephosphorylation of RNA polymerase by termination factors 12
31
*Eukaryotic vs. Prokaryotic Transcription* What are the RNAPs present in Bacteria/Archea?
only one form of RNAP
32
*Eukaryotic vs. Prokaryotic Transcription* What are the RNAPs present in Eukaryotes? List them
Multiple different types - RNAP I - RNAP II - RNAP III - RNAP IV/RNAP V
33
*Eukaryotic vs. Prokaryotic Transcription* What are the each specific RNA polymerase responsible for?
For producing different types of RNAs
34
*Eukaryotic vs. Prokaryotic Transcription* What RNA(s) does RNAP I produce?
rRNA
35
*Eukaryotic vs. Prokaryotic Transcription* What RNA(s) does RNAP II produce?
mRNA, snRNA, miRNA
36
*Eukaryotic vs. Prokaryotic Transcription* What RNA(s) does RNAP II produce?
mRNA, snRNA, miRNA
37
*Eukaryotic vs. Prokaryotic Transcription* What RNA(s) does RNAP III produce?
tRNA
38
*Eukaryotic vs. Prokaryotic Transcription* What RNA(s) does RNAP IV/V produce?
siRNA (plants)
39
*Eukaryotic vs. Prokaryotic Transcription* How many genes are transcribed in Prokaryotes?
polycistronic - Transcribe multiple genes at once - Genes are transcribed as operons
40
*Eukaryotic vs. Prokaryotic Transcription* How many genes are transcribed in Eukaryotes?
Monocistronic (ONE gene at a time)
41
*Eukaryotic vs. Prokaryotic Transcription* What is unique about RNA polymerase II?
Phosphorylation state of the C-terminal domain (CTD) changes with each stage of transcription
42
*Post Translational Processing* What are the 3 Steps to Process RNA? When do these steps occur?
1) 5' end is capped 2) Exon sequences are spliced together 3) Poly-adenylated tail (Poly-A) is added to the 3' end These steps occur alongside transcription, they are co-transcriptional
43
*Post Translational Processing* Why are Eukaryotic mRNAs capped?
1) To protect from ribonuclease 2) Enable binding to cap-binding proteins and ribosomes
44
*Post Translational Processing* What occurs during the capping of the 5' end? What are the results?
- Add 7-methylguanosine to 5' end - Enhanced stability - Roles in processing/translation
45
*Post Translational Processing* What do Poly (A) tails contribute to?
Roles in stability and translation
46
*Post Translational Processing* What are primary transcripts spliced into?
a continuous coding sequence
47
*Post Translational Processing* What are introns?
Sequences of RNA in between expressed regions of the transcript
48
*Post Translational Processing* What are exons?
Sequences of RNA transcript that code for protein
49
*Post Translational Processing* How do introns and exons vary in length?
Introns vary widely between 50-700,00 nucleotides ~1800 nucleotides on average Exons are relatively short less than 1000 nucleotides ~100-200 on average
50
*Post Translational Processing* What are the 2 splicing mechanisms?
1) Self-Catalyzed splicing 2) Spliceosome Mediated Splicing
51
*Post Translational Processing* Describe self catalyzed splicing - Where does it occur? - What are the 4 steps?
Occurs in RNA but NOT DNA 1) Driven by the higher reactivity of RNA given by the 2' OH 2) 2' OH specific Adenosine performs a nucleophile attack of the 5' splice site, forming lariat 3) Exposed 3' OH of 5' exon (the base at the 5' splice site was "stolen") now attacks the other side of the lariat 4) The lariat disassociated and the two ends of the exon are ligated together
52
*Post Translational Processing* What do Eukaryotes utilize on order to splice transcripts?
Spliceosome
53
*Post Translational Processing* What is a Spliceosome?
A large complex made up of small nuclear ribonucleo Proteins (snRNPs)
54
*Post Translational Processing* What do snRNPs contain?
specific small nuclear RNA to interact with specific sequences within pre-mRNA
55
*Post Translational Processing* What do snRNPs do?
Binds to intron and assemble to entire spliceosome to cut that region out
56
*Post Translational Processing* What do poly-A binding proteins regulate?
They regulate RNA export, breakdown, and aid in translation to protein
57
*Post Translational Processing* What 2 steps occur during the poly a tail addition?
1) Primary transcript is trimmed, leaving a consensus sequence at the 3' end 2) Polyadenylate polymerase adds 30 (yeast) to 100 (animals) A residues
58
*Post Translational Processing* What is alternate splicing? What does it result in?
the same "raw" transcript can result in two different mature transcripts these two different transcripts translate into two different protein sequences with different downstream effects
59
*Post Translational Processing* What does alternative splicing allow for?
Usually allows for tissue specific responses of a gene Allows more possible "outputs"
60
*Post Translational Processing* How is alternative splicing used to treat Spinal Muscular Atrophy?
- SMN1 protein is produced to mainatin motor neurons - SMA patients have a mutation in SMN1 gene - no protein produced leads to degeneration of neurons - Nusinersen effectively hides SMN2 RNA, affecting alternative splicing, producing a functional protein
61
*Different forms of RNA* Why is rRNA processed?
Ribosomal RNA is processed to produce proper ribosome structure
62
*Different forms of RNA* How is rRNA formed?
1) Modify many RNA nucleotides 2) Cut it into smaller pieces 1) Pieces come together to form 3 dimensional structure
63
*Different forms of RNA* Why is tRNA processed?
tRNA is processed to produce specific structures
64
*Different forms of RNA* How is tRNA formed?
A single strand of RNA forms intramolecular base pairs to fold into specific shapes
65
*Different forms of RNA* What helps govern the level of gene expression?
the cellular concentration of mRNA
66
*Different forms of RNA* Describe the relationship between the rate of mRNA synthesis and the rate of mRNA degredation
When synthesis = degradation, mRNA remains constant (steady state)
67
*Different forms of RNA* What
68
*Different forms of RNA* What does miRNA do? What is it utilized for?
Fine tunes gene expression Utilized to target specific sequences for either silencing or actual degradation
69
*Different forms of RNA* What is miRNA made of? Who utilizes miRNA?
22 nucleotide RNA oligomers Plants and Animals
70
*Different forms of RNA* What is unique about the structure of miRNA?
Near perfect complement mRNA sequences and can inhibit translation or degrade mRNA
71
*RNA Degradation* How is mRNA degraded in prokaryotes?
It is degraded by ribonuclease. Essentially: Individual proteins responsible for cleaving the RNA backbone and chewing up the polymer - They utilize enzymes known as endonuclease - They cut in the middle portion of the mRNA - Exonuclease's can come from the end and completely digest these particles themselves
72
*RNA Degradation* How is mRNA degraded in Eukaryotes? What enzyme do they utilize?
They utilize a very specific enzyme - endonuclease
73
*RNA Degradation* What is endonuclease? What does it do?
It's a large protein complex It unwinds and feeds mRNA through a nuclease for cleavage
74
*RNA and the origins of life* What is a Ribozyme? What does it suggest?
RNAs that fold into highly specific 3D shapes and catalyze reactions Suggests that perhaps there was an old version of enzymes made of RNA
75
*RNA and the origins of life* What is in the catalytic core of ribosomes composed of?
The catalytic core is composed of RNA

BIOL 0280 UNIT 4 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions