Brainscape's Knowledge GenomeTM

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


See full index

Block Two Cell Bio > Transcription and RNA II > Flashcards

Transcription and RNA II Flashcards

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

RNA in the cell

A

always found in the cell associated with proteins as ribonucleotideprotein complex; proteins are required for RNA to function (RNA cap Pol A binding proteins) and are protect RNA from degradation

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

Large ribonucelotideprotein complexes

A

can act as molecular machines to perform repetitive tasks such as RNA splicing and protein synth

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

mRNA

A

messenger RNA, codes for proteins

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

rRNA

A

ribosomal RNA form basic structure of ribosome and catalyze protein synth

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

tRNA

A

transfer RNA central to protein synth as adaptors between mRNA and amino acids

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

snRNA

A

small nuclear RNA; function in a variety of nuclear functions including splicing of pre-mRNA

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

snoRNA

A

small nucleolar RNA; help to process and chemically modify rRNAs

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

miRNA

A

microRNAs regulate gene expression by blocking translation of specific mRNA and cause their degredation (inhibit expression of specific mRNAs); 1st identified in nematode C.elegans; double stranded

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

siRNA

A

small interfering RNA; turn off gene expression by directing the degradation of selective mRNAs and the establishment of compact chromatin structures; first identified in plants; response triggered by dsRNA (double stranded); use for gene silencing and knockdown; double stranded

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

piRNA

A

piwi-interacting RNAs; bind to piwi proteins and protect germ line from transposable elements;

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

lncRNA

A

long non-coding RNA; serve as scaffolds, regulate diverse cell population, including X chromosome inactivation

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

primary transcript of protein coding gene

A

undergoes premRNA processing in nucleus to make mature mRNA; mRNA directs synthesis of protein once in cytoplasm

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

types RNA broadly

A

mRNA and non coding RNA which can be house keeping or regulatory

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

housekeeping ncRNA

A

tRNA rRNA

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

regulatory ncRNA

A

lncRNA and small ncRNA (microRNA, snoRNA, siRNA, snRNA, and piRNA)

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

Pre-mRNA processing

A

RNA capping RNA splicing RNA cleavage and polyadenylation

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

C-terminal tail of RNA Pol II

A

many of the processing factors bind to phosphorylated C terminal tail of RNA pol II and travel with the enzyme as RNA is synthesized

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

RNA capping

A

7’methyguanisin cap attached to 5’end nascent RNA by 5’ 5’ linkage; cap structure needed for RNA splicing, mRNA transport out of nucleus, mRNA stabilization, and translation of most mRNA

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

nuclear cap binding complex

A

mediates role of cap in nucleus

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

cytoplasmic eucaryotic initiation factor 4E

A

mediates role of cap in cytoplasm; targeted by viruses and misrelated in many cancers

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

RNA splicing

A

introns removed exons spliced together occurs in several steps uses lots ATP

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

narcolepsy in doberman

A

caused by splicing deffect insertion of repetitive element (SINE) w in intron 3 of hypocretin receptor2 gene leads to exon 4 not being retained bc 3’ splice site adjacent to exon 4 not recognized bc splice some not positioned correctly so 3’ splice site adjacent to exon 5 used instead

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

splicesome

A

large ribonucleoprotein complex that does RNA splicing

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

cis-splicing

A

splicing exons in same pre-mRNA molecule (usually this)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

trans-splicing

A

splicing exons of different pre-mRNA molecules (happens under certain conditions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Requirements for normal splicing

A

conserved RNA sequence at 5’ splice site, branch sequence, 3’ splice site, polypyrimadine tract located between branch sequence and 3’ splice site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

splicing steps

A
  1. begins with 2’ hydroxyl of adenine nucleotide in branch sequence attacking upstream intron/exon junction
  2. New phosphodiester bond formed leading to lariat structure; generating reactive hydroxyl group at 3’ end of exon
  3. 3’ hydroxyl attacks downstream intron/exon junction
  4. new phosphodiester bond created btwn 2 exons and releasing intron
28
Q

alternative splicing

A

different exons included in final transcript resulting in production of different mRNAs from same gene (90% primary transcripts from spliced genes alternatively spliced)

29
Q

increasing proteome complexity

A

spliced mRNA can encode proteins with distinct functional, structural, and regulatory properties

30
Q

splice variants in tumor

A

often promote proliferation, survival, and metastasis of cancer cells

31
Q

exons included in transcript

A

regulated by protein factors that bind to intronic and exonic sequences in RNA which promote or inhibit activation and assembly of splicsosome at specific site controlling whether exon is included in mature mRNA

32
Q

final step of pre-mRNA processing

A

occurs when RNA cleavage and poly A signals encoded in DNA are transcribed and recognized in RNA by proteins which cleave mRNA and add poly A tail

33
Q

poly A polymerase

A

post transcriptionally adds poly A tail to 3’ end processed RNA

34
Q

poly A tail

A

protects mRNA from degradation, tail shortens with each round of transcription

35
Q

poly A binding protein

A

required for mRNA to exit nucleus and to be efficiently translated

36
Q

stable mRNA

A

in general capped mRNA with poly a tail protected from degradation until poly A tail shortened as mRNA is translated; stability also regulated by specific nucleotide sequences and structural elements; these mRNA specific features bound to protein complexes that promote or inhibit mRNA degradation

37
Q

microRNA and small interfering RNA

A

regulate gene expression by promoting degradation of mRNA containing specific recognition sequence

38
Q

mRNA half lives

A

30min-15hrs; those encoding regulatory proteins (if TF) 30min those encoding structural protein (actin) 15hrs

39
Q

mRNA surveliance

A

cells assess mRNA quality as it is being translated and those that are abnormal get degraded before translation into protein complete

40
Q

nonsense mediated decay

A

mRNAs containing premature stop codons are recognized and degraded

41
Q

regulation of mRNA translation effect on cell

A

by regulating mRNA translation cells can rapidly change protein levels and consequently cell behavior in response to changes in internal and external envionrment

42
Q

4 phases of translation

A

initiation, elongation, termination, and recycling

43
Q

rate- limiting for protein synthesis

A

40S ribosome recruitment to mRNA during intiaiton important bc rate limiting for protein synth and frequently misregulated in disease

44
Q

circularization of mRNA

A

critical step required for ribosome recruitment and efficient translation of mRNA, required for initiation; circularization regulated by mTOR

45
Q

Steps of circularization of mRNA

A

in cytoplasm cap binding protein eIF4E interacts with eIF4G (initiation factor) once exit nucleus this complex displaces nuclear cap binding complex and binds to 5’ cap of mRNA eIF4G binds to poly a tail binding protein and brings 5’ and 3’ ends together to form circular structure

46
Q

mTOR

A

mechanisitic target of rapamycin; master regulator of cell metabolism and growth; this is a protein kinase; coordinates environmental input with cell metabolism and growth; works by controlling eIF4E which is inactive when bound to inhibitory protein 4EBP, mTOR phosphorylates and inactivates 4EBP which allows eIF4E to promote circularization and translation of capped mRNA

47
Q

mTOR in abundant nutrients

A

is activated and phosphorylates specific substrates that stimulate synthesis of lipids, nucleotides, proteins needed for cell growth and proliferation

48
Q

mTOR in nutrient starvation and energy depletion

A

is inhibited and consequently translation is inhibited

49
Q

mTOR and cancer

A

mTOR being activated stimulates cell growth and proliferation and may be hyper activated in cancer cases where mTOR leads to translation of proteins that promote specific tumor cell behaviors such as cell proliferation and survival, angiogenesis, tissue invasion, and metastasis

50
Q

viruses and cell replication

A

many viruses use virally encoded proteins to disrupt cell translational machinery and preferentially translate viral proteins

51
Q

disregulation of ncRNA

A

associated with neurodegeneration, immune disorders, cancer

52
Q

lncRNA

A

long non coding RNA; these have ability to regulate cellular processes via hybridization (base pairing) with specific DNA and RNA sequences; can also fold into 3D structures capable of binding specific proteins

53
Q

what do lncRNA regulate

A

nuclear architecture, transcription, post transcriptional processing, mRNA stability, and protein synthesis

54
Q

interfering RNA (RNAi)

A

both miRNA and siRNA inhibit gene expression and are considered interfering RNA; can use term RNA interference, gene silencing or gene knockdown; BOTH miRNA and siRNA are double stranded, recognize specific mRNA targets by base pairing

55
Q

dsRNA

A

usually siRNA perfect complement to target sequence while miRNA partially complimentary; both inhibit target mRNAs by stimulating degradation or blocking translation

56
Q

endogenous gene transcripts

A

miRNA derived from this; miRNA precursors transcribed by RNA pol II, capped, and polyadenylated in the nucleus

57
Q

miRNA vs siRNA

A

since miRNA only partially complimentary it has ability to target transcripts of 100s of genes simultaneously

58
Q

miRNA production

A

derived from dsRNA precursor; transcribed and processed in nucleus to produce double stranded miRNA precursor (pre-miRNA) which is exported to cytoplasm

59
Q

dicer

A

cleaves dsRNA progenitor of siRNA and the pre-miRNA in cytoplasm to produce mature versions

60
Q

RNA induced silencing complex (RISC)

A

miRNA and siRNA both associate with an argonuate protein as part of this; one strand of mi or si RNA used to direct RISC to mRNA target; w/ siRNA argonuate cleaves mRNA and promotes its degradation; miRNAs inhibit or promote degradation

61
Q

what does miRNA regulate

A

differentiation, proliferation, apoptosis; specific miRNAs for cardiac development, stem cell differentiation and regeneration

62
Q

altered miRNA

A

associated with cardiovascular disease, endocrine disorders, and cancer

63
Q

oncogene miRNA

A

over expressed in cancer; can act as oncogenes by inhibiting expression of genes that block tumorigenesis (tumor suppressor genes)

64
Q

tumor supressor miRNAs

A

inhibit the expression of oncogene mRNAs; often underexpressed or inactive in tumors

65
Q

RNAi in lab

A

used to silence genes to see what their function is; SIRT1 which is associated with pancreatic cancer is down regulated by RNAi making cells undergo apoptosis; RNAi against hair growth inhibitor makes long hair mouse; siRNA can be used to perform genome wide screening to ID novel signaling pathways and ID drug targets

66
Q

RNAi in clinic

A

being tested for metabolic, cardiovascular disorders, viral diseases and cancer with some success and some failure most recently was used to treat hereditary transthyretin amyloidosis (drug name is onpattro); some success in clinical trails treating cardiovascular disease and hemophilia

67
Q

Onpattro

A

FIRST RNAi drug to be FDA approved; lowers expression of mutant transthyretin gene

Block Two Cell Bio (9 decks)

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