P5 - RAS Flashcards

(33 cards)

1
Q

what is the need for a standard lane?

A

a comparison

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2
Q

what is the need for a control pre-induction sample/lane?

A

to observe no rab11 expression

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3
Q

what is the need for control post induction sample/lane?

A

to observe no rab11 expression

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4
Q

what is the need for a pre-induction lane/sample?

A

to observe no rab11 expression - induction needed to be done

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5
Q

should rab11 be detected in post induction, post sonfication lysate sample?

A

yes

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6
Q

should rab 11 be detected in soluble sample?

A

yes

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7
Q

should rab11 be detected in insoluble sample?

A

no

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8
Q

should rab11 be detected in unbound material?

A

no

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9
Q

should rab11 be detected in wash elute?

A

no

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10
Q

what weight is Rab11?

A

~20,100kDa

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11
Q

why do you need to wear gloves when handling acrylamide?

A

it is a neurotoxin

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12
Q

why must you be careful with acetic acid?

A

stain solution contains corrosive acid vapour

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13
Q

how big is the cDNA encoding Rab11?

A

1-173 residues

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14
Q

where was cDNA encoding Rab11 inserted into plasmid?

A

between NdeI and BamHI restriction sites

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15
Q

what plasmid was Rab11 inserted into?

A

pET28a

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16
Q

What E. coli strain has been engineered to maximise expression of foreign genes?

A

BL21DE3pLysSA

17
Q

How is Rab11 expressed?

A

induction by isopropylthiogalactoside (IPTG)

18
Q

How is the success of purification monitored?

A

SDS-polyacrylamide electrophoresis

19
Q

what antibiotic is used for Rab11 expression?

20
Q

using what absorbance is cell density monitored?

21
Q

how is cell density measured?

A

light scattering

22
Q

what happens E. coli growth during the exponential phase?

A

cells double every 20 minutes

23
Q

what measure of absorbance indicates that bacteria are in exponential phase?

24
Q

how long does it take bacteria to reach exponential phase?

A

approx 3 hours

25
why is SSSB and DSSB added to wells?
glycerol - helps sinking staining - helps observations uniform charging
26
what allows Rab11 to bind to nickel agarose?
affinity binding via His-tag
27
what is imidazole used for?
a rinsing buffer to unbind His-tag from nickel and form an elute of Rab11
28
why is protein purification necessary?
to examine its structure by crystallography
29
why is lysing necessary?
to break bacterial cell wall and allow access to proteins
30
what does SDS-lysis buffer do?
denatures proteins adds uniform charge for fair travel down gel
31
is SDS lysis buffer bias?
no, adds more charge if protein is bigger in size
32
why must this experiment be kept on ice at all times?
to prevent oxidation, proteolytic degradation
33
what can happen if proteins aggregate?
they can appear heavier than they are and become insoluble