Brainscape's Knowledge GenomeTM

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


See full index

Biology Module 6 > 19.2 controlling gene expression > Flashcards

19.2 controlling gene expression Flashcards

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

in what ways are genes regulated?

A

being turned on or off

increasing or decreasing the rate of production

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

why is gene regulation important?

A

allows for an organism to respond to different changes to the external and internal environments

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

what are the 4 ways of gene regulation?

A

transcriptional
post-transcriptional
translational
post-translational

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

what is transcriptional regulation?

A

when a gene is turned on or off

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

what is post-transcriptional regulation?

A

when the mRNA is modified to regulate translation

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

what is translational regulation?

A

when translation is tuned on or off

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

what is post-translational regulation?

A

when proteins are modified after synthesis to change their function

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

what is heterochromatin?

A

tightly wound DNA which allows DNA to be visible

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

what is euchromatin?

A

loosely wound DNA which prevents DNA from being visible

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

why cant DNA transcription occur in heterochromatin?

A

Heterochromatin is too tightly wound for RNA polymerase to operate

therefore transcription of DNA cannot occur

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

can euchromatin be transcribed?

A

as it is loosely wound, RNA polymerase can operate

therefore transcription occurs

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

how does euchromatin and heterochromatin regulate DNA transcription?

A

DNA is kept as euchromatin in interphase which allows for transcription

when in cell division, DNA is kept as heterochromatin which prevents transcription

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

why is the regulation of DNA transcription important?

A

prevents the waste of energy during protein synthesis as transcription is not happening all the time

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

how can histones become more negatively charged?

A

acetylation (adding acetyl groups)
phosphorylation (adding phosphate)

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

what is the effect of reducing the positive charge of a histone?

A

causes the DNA to coil less tightly which only allows for certain genes to be transcribed

histone (less positive with addition of acetyl/phosphate) has a weaker attraction to the negative DNA

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

how can histones become more hydrophobic?

A

methylation (adding a methyl group)

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

what is the effect of making the histones hydrophobic?

A

causes DNA to coil more tightly which prevents the transcription of genes

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

what is epigenetics?

A

the control of gene expression by modifying the DNA

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

what is an operon?

A

group of genes under the control of a regulatory mechanism

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

which organisms mainly have operons?

A

prokaryotes

21
Q

why are operons useful?

A

by regulating protein synthesis, operons can save resources when a protein is not needed

22
Q

what is the lac operon composed of?

A

lacZ
lacY
lacA

23
Q

what is a structural gene?

A

section of DNA which codes for a protein/enzyme

24
Q

what is a regulatory gene?

A

section of DNA which codes for a transcription factor

25
Q

what is a transcription factor?

A

a protein which either switches genes on or off

on = activator
off = repressor

26
Q

what is the operator?

A

section of DNA where the transcription factor binds to

27
Q

what is the promoter?

A

section of DNA where the RNA polymerase binds to

28
Q

what are introns?

A

non-coding sections of DNA

29
Q

what are exons?

A

coding sections of DNA

which are EXPRESSED

30
Q

how does a transcription factor turn on a gene?

A

binds to the operator in an operon to cause RNA polymerase to bind to the DNA and activate

ACTIVATOR

31
Q

what role do inhibitors play with transcription factors?

A

they bind to transcription factors and cause a conformational change preventing it from binding to the operator

32
Q

how is the lac operon turned off?

A

a repressor gene produces a repressor which, when bound to the operator, prevents the binding of RNA polymerase to the DNA at the promoter and thus prevents transcription

33
Q

how is the lac operon turned on?

A

in the presence of lactose, lactose molecules bind to the repressor causing it to deactivate (by changing it’s shape) which stops it binding to the operator and allows RNA polymerase to bind to DNA at the promoter

34
Q

what can increase the rate of transcription of structural genes?

A

cAMP

35
Q

what does cAMP bind to to increase the rate of transcription?

A

CRP

36
Q

if glucose and lactose are both present what is metabolised and why?

A

glucose

increase in glucose conc, decreases the cAMP conc which means less transcriptions of genes needed for lactose metabolism

37
Q

what are the two methods of post-transcriptional control?

A

RNA processing
RNA editing

38
Q

what is produced at the end of transcription?

A

pre-mRNA

39
Q

what is RNA processing?

A

conversion of pre-mRNA to mature mRNA by splicing

40
Q

what is splicing?

A

the removal of introns and the joining of exons to produce mature mRNA

41
Q

what is RNA editing?

A

when the codons are mixed up

means that a range of proteins are produced from a single strand of mRNA

42
Q

in what ways is translation controlled?

A

degradation of mRNA
inhibitory proteins
initiation factors

43
Q

degradation of mRNA

A

damaged mRNA molecules cannot bind to the ribosome so translation cannot occur

44
Q

inhibitory proteins

A

bind to mRNA to prevent it from binding to ribosomes

45
Q

initiation factors

A

aid mRNA in binding to ribosomes

46
Q

what are protein kinases?

A

enzymes which catalyse phosphorylation to proteins

causes a change in the protein’s structure and function

47
Q

what ways is post-translational control carried out?

A

addition of non-protein groups
modifying amino acids
folding of proteins
modification by cAMP

48
Q

how does cAMP carry out post-transcriptional control?

A

binds to proteins to change the tertiary structure causing it to activate or deactivate

Biology Module 6 (33 decks)

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