Brainscape's Knowledge GenomeTM

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


See full index

Biol 207 > Topic 3: Genetic Regulation > Flashcards

Topic 3: Genetic Regulation Flashcards

1
Q

What is a gene

A

Sequence of DNA that encodes a specific trait or product

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

Turning genes on/off in bacteria vs eukaryotes

A

Bact = turn genes on/off in response to environment
Euk = turn genes on and off in response to environment, for cell differentiation, tissue coordination, based on developmental stage

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

Where can gene expression be controlled

A

Before transcription (important, first step before DNA->RNA->protein)
Post transcription
Translation
Post translation

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

Which part of gene expression control do prokaryotes not have

A

mRNA processing

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

What are structural genes? what are they controlled by?

A

Genes that encode proteins (e.g. enzymes), controlled by DNA binding proteins

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

What do DNA binding proteins control, what are they produced by

A

Control structural genes
Produced by regulatory genes

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

What are regulatory genes?

A

Encoding products that interact with other sequences and affect the transcription and translation of these sequences
Make DNA binding proteins

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

What are regulatory elements

A

DNA sequences that are not transcribed but play a role in regulating other nucleotide sequences

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

What kind of proteins are transcription factors

A

DNA binding

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

What can DNA binding proteins recognize? What do they form bonds with? What type?

A

Information in the major and minor grooves of DNA
Form H-bonds with groups on the bases

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

What is a protein domain

A

~60-90 amino acids, responsible for doing a specific job or forming a specific structure

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

What is a motif

A

Within the binding domain, a simple structure that provides specificity (recognizes DNA seq)

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

Domains and motifs are found in…

A

DNA binding proteins

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

Examples of protein domains

A

Helix-turn-helix
Zinc fingers
Leucine zipper

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

What are operons

A

In bacteria, a set of related genes are regulated together
Transcribed as a single mRNA with multiple coding regions
Controlled by the same promoter and regulatory proteins
Multiple proteins transcribed off single mRNA with diff start and stop codons

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

Operons are regulated at the…

A

Operator

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

Slide 10

A

Operon

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

What is constitutive expression

A

Continuously expressed under normal cellular conditions

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

What is positive control? Negative control?

A

+ = control at the operator is positive ie TF that binds operator stimulates transcription
- = control at the operator is negative ie TF that binds operator inhibits transcription (repressor)

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

What is an inducible operon? Repressible?

A

Inducible = transcription is usually off, needs to be turned on
Repressible = transcription is normally on, needs to be turned off

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

What is the regulatory gene doing in negative inducible control? Negative repressible control?

A

Neg inducible = regulatory gene that controls operon produces a repressor, normally active
Neg repressible = regulatory gene makes a repressor, normally it is inactive

22
Q

Slides 14, 15, 16, 17***

A

Neg repressible and inducible

23
Q

What is positive control

A

Regulatory protein involved is an activator
Operator can be inducible or repressible

24
Q

What is controlled by positive and negative control

A

Transcription

25
Q

Structural genes of the lac operon and their functions

A

lacZ: encodes B-galactosidases (metabolism of lactose)
lacY: encodes permease (transport lactose into cell)
lacA: encodes transacetylase

26
Q

What kind of system is the lac operon

A

negative inducible

27
Q

What are the regulatory genes/elements of the lac operon

A

lacI: repressor encoding gene (produces repressor protein LacI)
lacP: operon promotor (RNA polymerase assembles)
lacO: operon operator (LacI binds)

28
Q

Under normal conditions, the lac operon is…

A

off

29
Q

What is the inducer of the lac operon? What does it do?

A

allolactose (binds LacI and changes its conformation to deactivate it/close active site)

30
Q

Does repression completely shut down transcription

A

No, tiny amount ongoing

31
Q

What is permease

A

membrane protein that transports lactose into the cell

32
Q

What does B-galactosidase do to lactose

A

Converts it to allolactose or galactose+glucose

33
Q

In the presence of lactose, does transcription continue?

A

Yes, allolactose binds the repressor protein and prevents it from binding the operator

34
Q

What is the partial diploid lac mutation

A

Full bacterial chromosome + an extra piece of DNA on F plasmid (genomic copy+plasmid copy)

35
Q

What is the plasmid in partial diploids

A

Extra piece of DNA that can carry a fully functional complement of the lac operon

36
Q

What does the partial diploid mutation allow us to do

A

Mutate different components on the genomic or plasmid copies

37
Q

What is the structural gene mutation of the lac operon

A

Affects the structure of the enzyme but not the regulations of their synthesis

38
Q

What is wrong with lacY-? lacZ-?

A

y- = no functional permease
z- = no functional B-gal
No metabolism of lactose

39
Q

How do pseudodiploids help with structural gene mutations of the lac operon

A

The genomic copy may have a non-functioning gene, but if the plasmid has the wildtype gene then there is functioning lactose metabolism (or vice versa)

40
Q

What are regulator gene mutations in the lac operon

A

Affect the actions of the regulator protein (producing LacI)

41
Q

What are operator mutations in the lac operon

A

Affects the function of the operator
lacO^c = no operator
Dominant over lacO+ because the operators are cis acting

42
Q

Which is dominant, lacI- or lacI+

A

lacI+, genes are trans acting, normal regulation of operon

43
Q

What are cis vs trans genes

A

cis = acting on the same piece of DNA its located on
trans = act on different pieces of DNA

44
Q

Slides 24 -> 32**

A

Lac operon mutations

45
Q

What is the promotor mutation

A

lacP-
cis acting
non-functional P = RNA polymerase cannot assemble

46
Q

What is positive control through catabolite repression

A

Using glucose when available and repressing the metabolism of other sugars
High levels of glucose repress the lac operon, low levels of glucose STIMULATE the lac operon

47
Q

Positive control can occur through..

A

catabolite repression

48
Q

How does the cell know when glucose is present

A

cAMP, its concentration is inversely proportional to the level of available glucose

49
Q

What complex is the positive regulator of the lac operon

A

cAMP/CAP complex (binds and stimulates transcription of operon; activator)

50
Q

Slides 36/37

A

Positive control of lac operon

51
Q

What happens to the structure of DNA when cAMP-CAP binds

A

Produces a sharp bend in DNA that activates transcription

Biol 207 (22 decks)

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