Genes Flashcards

1
Q

Define gene

A

entire DNA sequence required to direct protein synthesis.

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

What is DNA

A

The molecule that contains genetic information

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

What is the size of the human genome in MB?

A

3200

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

What is the size of the human gene number

A

31000

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

What is the size of the bacteria gene number

A

4000

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

What is the size of the bacteria geneome MB

A

4

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

What are the basic steps to get from DNA to a protein.

A

DNA replicates then gene is transcribed then RNA is translated to amino acids to make a protein

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

What is the label for the binding point for RNA polymerase?

And what are the labels for the bases to the left and to the right of this?

A

+1 / promotor region

Bases to the left = -ve
Bases to the right = +ve

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

Which direction on the DNA does the RNA polymerase move?

A

5’ to 3’

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

What is the bases at the start and end of the coding region?

A

Start- ATG

End- TAG or TAA or TGA

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

If more protein is required how does this affect mRNA synthesis and Protein synthesis

A

Greater mRNA and Protein synthesis

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

What are the 2 ways that bacteria control transcription?

A

Constitutive expressed genes

Regulated genes

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

How are bacterial promotors recognised by RNA polymerase?

A

Has a consensus / common pattern of DNA

hexamer (6bp) at -35 and a TATAAT sequence at -10

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

What is the consensus DNA in a bacterial promotor?

A

hexamer (6bp) at -35 and a TATAAT sequence at -10

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

How many types of subunits does the RNA polymerase / holoenzyme molecule have and what are they?

A
4 types 
2 Alpha
Beta 
Beta prime
sigma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the roles of the subunits in RNA polymerase?

A

Alpha - enzyme assembly promotor recognition binds to some activators

Beta and Beta prime = catalytic center

sigma= promotor specificity recognising -35 and -10

17
Q

Describe bacteria Transcriptional initiation

A

Specific binding at sigma to -35 -10 promoter sequence
DNA unwound at initiation site
Initiation of transcription and release of sigma to elongate.

18
Q

Describe bacterial elongation

A

RNA polymerase moves from 5’ to 3’ end of the DNA forming a DNA/RNA hybrid helix before the Nascent RNA is formed 5’ to 3’

19
Q

Describe bacteria termination

A

RNA polymerase stops at termination site - TAG or TAA or TGA.
THE RNA polymerase separates and RNA is released

20
Q

What are the 2 mechanisms of control in transcription in bacteria?

A

Use of alternative sigma factors

Transcriptional regulators

21
Q

Name the 2 types of transcriptional regulators

A

Negative regulation

Positive regulation

22
Q

Describe negative regulation of transcription

A

Repressor binds to operator sites to prevent RNA polymerase from binding

23
Q

Describe positive regulation of transcription

A

Activators bind to specific site helps RNA polymerase binds

24
Q

What is the role of the Lac operon?

A

Switches on genes that encodes enzymes which are needed to metabolise that sugar

25
Define operon
region of DNA that contains clusters of related genes, made up of promotor region, operator and multiple related genes
26
What 3 genes make up the lac operon, how many bp and what proteins do they make?
lacZ-3072bp- Beta Galactosidase lacY-1251bp-Permease lacA-609bp-Transcetylase
27
What is the role of Beta Galactosidase
cleaves lactose into its component sugars
28
What is the role of permease
Transports lactose into cells
29
What is the role of transacetylase
Covalently modifies lactose
30
What is the lac operon regulated by?
Negative and positive regulators Lac repressor,CAP activating protein
31
Where does the Lac repressor bind and how does it regulate when lactose is absent?
Binds to operator and blocks transcription
32
Where does the Lac repressor bind and how is it regulated when lactose is present?
Allolactose produced which binds to the lac repressor | This induces a conformational change so repressor cannot bind to the operator
33
What are transcriptional activators used for?
Allows promorters to be better recognised b y RNA polymerase
34
What is glucose relationship to the lac operon?
High Glucose- Lac operon off | Low glucose- Lac operon on ( alternative sugar source is lactose)
35
Describe the CAP/ Catabolite ACtivator Protein function
In low Glucose the cAMP levels are high SO CAP active and Lac operon activated vice versa for high glucose