Brainscape's Knowledge GenomeTM

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


See full index

Y2S2 - Adv. Molecular Biology > MolBio9-10 - 52 > Flashcards

MolBio9-10 - 52 Flashcards

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

What are the 6 points of protein expression control?

A

Transcriptional control, processing control, RNA transport and localisation, translation control, mRNA degradation control, protein activity control

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

What is the primary purpose of gene control?

A

The execution of precise developmental descisions so that the proper gene is expressed in the proper cell at a proper time

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

What is the main mode of transcriptional control?

A

Transcriptional initiation control

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

How do transcriptional activator exert their effect?

A

Either directly, by recruiting one of the components of the transcriptional machinery, or indirectly, by modulating the chromatin structure

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

What are transcriptional activators and repressors?

A

Modular proteins containing separate DNA-binding and activation/repression domains

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

What are the 4 most common DNA binding motifs?

A

Homeodomain, Zn finger, leucine-zipper and bHLH

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

What do cooperative binding and combinatorial control achieve?

A

Transcriptional efficiency, specificity and yet diversity of responses

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

Describe transcriptional activators

A

Modular proteins with an activation domain and a DNA-binding domain

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

Give an example of a homeodomain protein

A

Hox

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

Describe the homeodomain protein

A

60 aminoacid domain, 3 helices

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

Give an example of a zinc finger protein

A

Ci (in Hh signalling)

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

Describe the zinc finger

A

23-26 aminoacid motif (C2H2), 2 cys and 2 his bind to Zn

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

Give an example of a leucine zipper

A

Fos

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

Describe the leucine zipper

A

Leu separated by 7aa in a helix, two major grooves separated by 1/2 turn

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

Give an example of a basic helix-loop-helix protein

A

MyoD

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

What are the two activation effects?

A

Cooperative binding - increased affinity of RNA polymerase for promoter; allostery - transition from closed to open complex

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

What is the advantage of cooperativity?

A

Greater specificity

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

What are the four methods of repression?

A

Competition, inhibition, direct, and indirect

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

What is EMSA?

A

Electrophoretic mobility shift assay

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

Outline EMSA

A

Tagged DNA, probe washed through DNA that will bind to regulatory sequences, gel retardation to find where bound

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

What is ChIP?

A

Chromatin immunoprecipitation assay

22
Q

Outline ChIP

A

Antibody for specific activator/repressor added in to in vivo sample, and DNA that has formed a complex with that activator/repressor will be precipitated out, and the sequence subsequently identified

23
Q

What does epigenetic mean?

A

Systems that sit on top of genetic mechanisms

24
Q

What is special about epigenetic alterations to the genome?

A

Erased in germ cells

25
Q

Where are nucleosomal modifications made?

A

Termini of lysine, arginine and serine side chains

26
Q

What is a condition of nucleosomal modifications?

A

Mutually exclusive of one another

27
Q

What are the main 3 nucleosomal modifications?

A

Acetylation, methylation and phosphorylation

28
Q

What are the main two nucleosomal modification enzymes?

A

Acetyltransferase and methyltransferase

29
Q

What to acetyltransferases do?

A

Indeterminately acetylate any lysine residue

30
Q

What do methyltransferases do?

A

Very specifically methylate specific residues

31
Q

What does acetylation of core hostones do?

A

Creates binding sites for transcriptional activation factors that contain a bromodomain

32
Q

What does methylation of core histones do?

A

Creates binding sites for transcriptional repressors that contain a chromodomain, or activators that contain a PHD zinc finger domain

33
Q

What reads the histone modifications?

A

Histone Code Reader proteins

34
Q

What is the function of histone code reader proteins?

A

To facilitate attachment to other components in nucleus, leading to gene expression, gene silencing, or other biological functions

35
Q

What is the relationship between histone code readers and code writers?

A

They can recruit each other, helping spread histone code in chromatin, which impacts on gene expression

36
Q

In what 4 ways do transcription activator proteins work?

A

Selective nucleosome remodelling, selective histone removal, selective histone replacement or selectin histone modification

37
Q

What does PRC stand for?

A

Polycomb Repressive Complexes

38
Q

What are PRCs?

A

Histone Code Writers/Readers that can generate or recognise repressive chromatin modifications

39
Q

Name one example of repressive chromatin modification

A

H3-K27 methylation by Ezh2 of PRC2

40
Q

Name one example of respressive chromatin modification identification

A

Pc chromodomain identification and subsequent recruitment of PRC1

41
Q

What is the relationship between DNA methylation and repressive histone methylation?

A

Close functionally - transcriptionally inactive promoters are frequently rich in methylated CpG dinucleotides

42
Q

Why is mammalian X-chromosome inactivation important?

A

Equalizes the levels of X-chromosome derived gene products in males and females

43
Q

Outline mammalian X-chromosome inactivation

A

Essentially dosage compensation: males have XY so only 1 dose; females have XX so 2 doses. One is always silent and once is transcriptionally active, the choice is random, and occurs early embryogenesis, and is then clonally inherited

44
Q

Give a visual example of mammalian X-chromosome inactivation

A

Tortoise shell cats - XO orange; Xo black. Males are orange or black, females are orange, black or calico. Calico is patchy because of random X-inactivation during early embryogenesis

45
Q

Outline the mammalian X-chromomsome inactivation mechanism

A

Involves synthesis of a non-coding RNA (Xist) from the X-inactivation centre, which binds to the chromsome in cis and promotes chromatin condensation by recruiting PRC group components

46
Q

What is the Barr body?

A

Highly condensed inactive X chromosome at the preiphery of the nucleus of female somatic cells

47
Q

What is position effect variegation?

A

Relocation of two functionally distinct regions of genes - euchromatin and heterochromatin

48
Q

Describe euchromatin

A

Transcriptionally active genes

49
Q

Describe heterochromatin

A

Transcriptionally silent genes

50
Q

What does abnormal reanets of euchromatin and heterochromatin cause?

A

Position effects that affect the transcriptional activity of the euchromatic genes

51
Q

What can aberrant chromsomal rearrangements cause?

A

If heterochromatin is placed next to euchromatin, it can shut down gene activity - the dominant effect is from the heterochromatin to the euchromatin, effectively spreading the silence

52
Q

Is position effect variegation complete?

A

No - some transcriptional activity of the euchromatin usually remains

Y2S2 - Adv. Molecular Biology (14 decks)

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