Gene regulation Flashcards

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

Demands for the synthesis of certain proteins may change, for instance in development, during which the degree of expression of several genes can vary according to the precise _____ of the cell and also w/ _____.

A

location; time

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

Immediately upstream of the gene is the _____, which is involved in the binding of RNA polymerase II to the DNA template strand.

A

promoter

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

Promoters for RNA polymerase II are usually several hundred nucleotides long and often contain a consensus sequence called the _____.

A

the TATA box (TATAAA)

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

The TATA box, usually located around _____ upstream of the transcriptional start site, binds, via the so - called ____ subunit of TFIID, to a series of general transcription factors which are relatively abundant proteins used to initiate the transcription of nearly all mRNAs.

A

25 bp; TATA – binding protein (TBP)

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

These are relatively abundant proteins used to initiate the transcription of nearly all mRNAs.

A

Transcription factor

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

The TATA box, usually located around 25 bp upstream of the transcriptional start site, binds, via the so - called TATA-binding protein subunit of _____, to a series of general transcription factors which are relatively abundant proteins used to initiate the transcription of nearly all mRNAs.

A

TFIID

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

Basal transcriptional efficiency is commonly aided by the presence of other upstream _____ within the promoter region.

A

short consensus regulatory sequences

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

Short consensus regulatory sequences include multiple copies of the so - called _____, which binds the ubiquitous transcription factor SpI, and the _____, which is typically located 75 bp upstream of the transcriptional start site and binds the transcription factors CTF and CBF.

A

GC box;CAAT box

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

What does the short consensus regulatory sequence GC box recognize?

A

TF SpI

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

What does the short consensus regulatory sequence CAAT box recognize?

A

TF CTF and CBF

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

CAAT box, which is typically located _____ bp upstream of the transcriptional start site and binds the transcription factors CTF and CBF.

A

75

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

The activity of many promoters is modulated by one or more _____.

A

enhancers

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

Enhancers are generally short sequences, with a length of _____ bp, that bind specific transcription factors.

A

less than 20-30

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

T/F. Most enhancers function whether on the coding or non - coding strand of DNA and can be located, in either orientation, up to several kilobases from their target promoter.

A

True

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

Most enhancers are active only in specific cell types and thus play a central role in _____ of gene expression.

A

regulating tissue specificity

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

_____ are similar to enhancers but, in contrast, inhibit transcription of the associated gene.

A

Silencers

17
Q

The large number of specific transcription factors and their interaction at individual enhancers allows complex patterns of gene activation in response to particular circumstances including _____ and _____.

A

tissue differentiation; physiological or pathological receptor signaling

18
Q

Interactions between the proteins bound to enhancers and those bound to the promoter sequences are probably permitted by _____.

A

loop formation of the intervening sequences

19
Q

About _____ percent of genes are only expressed at specific times and places (e.g. insulin in the pancreatic islet β - cells). The other _____ percent, which are called _____, are expressed in all tissues, generally fulfill basic metabolic needs and account for _____or more of the genes expressed in any particular cell type.

A

80%; 20%; housekeeping genes; 90%

20
Q

The majority of housekeeping genes and about 40% of tissue - specific genes have _____ near their 5 ′ ends.

A

CpG islands (indicated as C, p for phosphate, G, to distinguish them from G hydrogen bonded to C in opposite DNA strands)

21
Q

The CpG islands are about _____ in length and contain a high proportion of 5 ′ - CG - 3 ′ dinucleotide pairs.

A

1 kb

22
Q

The _____ are about 1kb in length and contain a high proportion of 5 ′ - CG - 3 ′ dinucleotide pairs.

A

CpG islands

23
Q

The CpG islands are about 1kb in length and contain a high proportion of _____ dinucleotide pairs.

A

GC

24
Q

T/F. Generally, cytosine residues in CpG dinucleotides are methylated, but in CpG islands associated with active neighbouring gene expression, there is usually a lack of methylation.

A

T

25
Q

Although the bulk of regulation probably occurs at the transcriptional level, regulation of a gene ’ s activity may also occur later with:

A

alteration of the rate of protein translation or degradation

alternative splicing of the mRNA to produce different gene products (e.g. calcitonin or calcitonin gene - related neuropeptide).

26
Q

Mutations within a gene ’ s regulatory sequences can occur and may result in:

A

no gene product, e.g., beta-thalassemia

abnormal persistence of a fetal gene product, e.g., hereditary persistence of a-fetoprotein or hemoglobin F

anomalous patterns of gene expression, e.g., ectopic expression of creatine kinase