Control of gene expression Flashcards

exam 1

1
Q

cell types are determined by

A

differential gene expression resulting in different proteins

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2
Q

basic functions for cell sustenance

A

Housekeeping

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3
Q

example of a housekeeping gene

A

ribosomal proteins

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4
Q

formed as DNA wraps around a histone octamer

A

nuclesome

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5
Q

nucleosomes are not accessible to ______ when compared to free DNA

A

DNase I

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6
Q

trasncriptionally inactive

A

heterochromatin

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7
Q

transcriptionally active

A

euchromatin

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8
Q

accessible to limiting amounts of DNase I

A

euchromatin

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9
Q

not accessible to limiting amounts of DNAse I

A

heterochromatin

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10
Q

requires chromatin structure rearrangement so that RNA polymerase may bind

A

Gene activation

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11
Q

regulate chromatin organization over chromosomal domains

A

Locus control regions

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12
Q

LCR example

A

all globin genes

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13
Q

can alter chromatin structures

A

protein complexes

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14
Q

protein complexes that can alter chromatin structure example

A

SWI-SNF

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15
Q

Protein Complexes are thought to act globally to ____ mobility of ________ throughout the genome but some may target specific genes

A

Protein Complexes are thought to act globally to increase mobility of nucleosomes throughout the genome but some may target specific genes

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16
Q

leads to unfolding of chromatin leading to transcritptional activation

A

histone acetylation

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17
Q

histone acetylation happens in

A

lysine residues

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18
Q

Many transcriptional “activators” have histone ____________ activity

A

acetyltransferase (HAT)

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19
Q

Many transcriptional “repressors” are histone _________

A

deacetylases (HDAC)

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20
Q

diminished gene expression

A

presence of methyl groups in promoter regions

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21
Q

gene activity associated with

A

absence of methylation

22
Q

key mediator of X-inactivation

23
Q

____ _________ adds a methyl group to the _____carbons atom of some, but not all, cytosine residues in ____ ________

A

DNA methyltranserase adds a methyl group to the fifth carbon atom of some, but not all, cytosine residues in CpG dinucleotides

24
Q

CpG dinucleotides sequences are _______ for mutations because ______ of 5-methyl cytosine forms _____ and _____ _____ will not register this as a mutation

A

CpG dinucleotides sequences are hotspots for mutations because deamination of 5- methyl cytosine forms thymine and repair machinery will not register this as a mutation

25
long CpG rich regions of DNA present in promoter regions that are actively transcribed in all cell types
CpG islands
26
True or false: About 75% of human genes have a CpG island near their enhancers regions
false: About 50% of human genes have a CpG island near their promoter regions
27
almost always lack methylation, regardless of whether the associated gene is active or nor
CpG islands
28
certain genes are ______ by various signals
induced
29
marked by protein binding to promoter or enhancer elements facilitating transcription
Inducible gene expression
30
made in the pancreas
insulin
31
example of hormonal induction signal
steroid hormones
32
regulated by glucose via the PDX1 gene
insulin
33
derived from cholesterol and are soluble in lipid membranes
cholesterol
34
Cholesterol receptors are ______ and once bound to hormone these receptors bind to _______ or ______ elements of DNA
Cholesterol receptors are intracellular and once bound to hormone these receptors bind to response or enhancer elements of DNA
35
used to determine differences in the mRNA population between two cell types
DNA microarrays
36
requires mRNA isolated from two cell types
Microarray
37
Microarray measures relative _______ in mRNA populations. Glass slides containing the ____ of interest is prepared by ________ the dsDNA so that ________ is available for complementary base pairing.
Microarray measures relative differences in mRNA populations. Glass slides containing the DNA of interest is prepared by denaturing the dsDNA so that ssDNA is available for complimentary base pairing
38
(1) continuation of microarray. mRNA from each cell type is converted to ____ and labeled with a particular ____ probe. The ____ are pooled and _____ to the DNA on the microarray. Microscopes and computers are used to measure the amount of ________ to all of the spots on the microarray
mRNA from each cell type is converted to cDNA and labeled with a particular fluorescent probe. The cDNA are pooled and hybridize to the DNA on the microarray. Microscopes and computers are sued to measure the amount of hybridization to all of the spots on the microarray.
39
(2) continuation of microarray. If a particular ______ is present at abnormal levels in once cell type compared to the other, the spot will not ___________________________
If a particular mRNA is present at abnormal levels in once cell type compared to the other, the spot will not blend of the two colors but rather on primary color
40
alternative to microarray
RNA-seq
41
RNA-seq relies on?
next generation sequencing to determine the composition and quantity of RNA present in a cell.
42
true or false: in RNA-seq, the more sequence that appears, the more RNA is present
true
43
excessive _______ expression is seen in multiple diseases
mRNA
44
is used for RNA interference methods (RNAi)
small-interfering RNA (siRNA)
45
ds-siRNA froms a
ribonucleoprotein complex--> RISC
46
RISC binds to
target mRNA via complementary base pairing
47
RNA interference leads to?
targeted destruction of "knock-down" of the bound mRNA
48
can be used to "knock-out" specific genes
CRISPR-Cas
49
programmable nuclease that can be guided to certain sites on DNA
Cas9
50
true or false: there exists a possibility of never correcting gene defects in the future
false, YES WE CAN!!!
51
knock-out
CRISPR-Cas
52
Knock-down
RNAi