Receptors, signals ans responses Flashcards

1
Q

why is cell communication important?

A

there are lots of tissues, organs + cell types in the human body - need to keep responding to changes in environment.

Growth, infection, blood glucose, wounds, and time to die.

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

3 important steps in cell signalling

A

signal, receptor, response

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

cellular response without a signal can lead to

A

cancer

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

over reacting immunity signals

A

inflammatory response

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

not responding to immunity signals

A

immunodeficiency

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

which cells make insulin?

A

Beta cells in the islets of lagerhands, located in the pancreas

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

what do the alpha cells in the pancreas make?

A

glucagon

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

what happens when there are low blood sugar levels?

A

glucagon is released, tells the cells that you need fat cells to start releasing their energy source to maintain blood sugar levels

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

ENDOCRIN SIGNALLING

A

hormone secretion into the blood by an endocrine gland - to act on distinct target cells in the body

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

PARACRINE SIGNALLING

A

cells secrete signals close to the target cells

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

what are direct contacts?

A

in the epithelial sheet forming connections between cells.

they detect signals from neighbouring cells and the ECM (how rigid is the ECM)

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

what is synaptic signalling

A

where nerve cells release neurotransmitter into the synaptic cleft - taken up and causes a response in the target cells

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

example of hormones that use endocrine signalling

A

testosterone and insulin

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

examples of paracrine signalling

A

growth factors, cytokines (immune cells), NO

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

what are neurotransmitters derived from/

A

amino acids

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

what are steroids derived from?

A

cholesterol

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

example of a small molecule signal

A

adrenaline

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

examples of peptide hormones

A

hCG, LH

insuline

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

example of a steroid hormone

A

testosterone

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

what are the 4 main receptor types

A

steroid receptors, G protein coupled, ligand gated channels, enzyme linked

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

what are 2 main types of repsonsed to signals

A

Turn genes on or off

Modulate the activity of cellular proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are steroid receptors?

A

they are transcription factors/activators that turn genes on and off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

are steroid lipophilic or hydrophilic?

A

lipophilic

so they diffuse across cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

where would you find a steroid receptor?

A

in the nucleus or cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

sequence of events for steroid receptors

A

2 steroid receptors – form dimer – only in this form can the steroid recpetors act as transcription factor – need to bind to enhancer – induce recruitment of standard transcription machinery to the proton region (initiation complex) and then polymerases transcribe the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the enhancer region do?

A

coordinated signals and timing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what provides specificity for steroid receptors?

A

Different steroid receptors bind different steroids and different steroid receptors different enhancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

which drug is used for medical abortions?

A

Mifepristone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how does Mifepristone work in abortions?

A

receptor antagonist, antagonises the progesterone receptor, stop the cells being able to produce progesterone, progesterone cannot maintain pregnancy

30
Q

what is cushing’s syndrome?

A

over production of cortisol (adrenal gland tumours)

31
Q

how would you treat cuttings syndrome?

A

Making too much steroid – inhibitors which inhibit pathway where cholesterol is turned into cortisol – blocking the formation of signal

using ketonazole metyrapone

32
Q

what drug would you use to break cushings

A

Ketoconazole Metyrapone

33
Q

ligand gated ion channels open in response to…

A

a signal to allow ions to flow through

34
Q

what type of receptors do neuromuscular junctions use?

A

ligand gated ion channels

35
Q

what happens in neuromuscular junctions?

A

Ach is released into the synaptic cleft from the vesicles in the presynaptic knob, when the vesicles fuse with synaptic membranes they bind to the receptors and allow ions to flow through the channels into the muscle

36
Q

which enzyme mops up/breaks down Ach?

A

Acetylcholinesterase

37
Q

how does botulinum toxin work to stop muscle movement?

A

it inhibits Ach release, so there is no AP and so no muscle contraction

38
Q

what affect does nerve gas have on muscle contraction and why?

A

nerve gas inhibits AchE - Ach can’t be broken down so you get constant signal - excessive muscle contraction

39
Q

what fraction of human genes code for GPRCs

A

1/20 genes

40
Q

what percentage of pharmaceuticals work on GPRCs

A

40%

41
Q

examples of what some GPRCs do

A

Immune modulators (chemokines), taste and smell, hormones (adreneline) synaptic (some) , eyes use to detect light

42
Q

how does adrenaline affect skeletal and cardiac muscle - lung bound to GPRCs

A

More energy
Increased blood and air (vasodilation)

Weaker contraction (smooth muscle)
Stronger contraction (skeletal muscle)
43
Q

how does adrenaline affect gut and skin bound to GPRCs

A
Less energy
Less blood (vasoconstriction)

Stronger contraction (smooth muscle)

44
Q

the same hormone can bind to

A

different receptors

45
Q

where would you find a1 adrenoreceptors

A

in the GI tract

46
Q

what response do a1 receptors have to adreneline

A

smooth muscle contraction and casoconctriction

47
Q

where would you find B1 arenoreceptors

A

heart

48
Q

what response do B1 adrenoreceptor have to adrenaline

A

inc. heart muscle contractility

49
Q

where would you find B2 adrenoreceptors

A

in the lungs

50
Q

what response would you get if B2 receptors were stimulated with adrenaline

A

smooth muscle relaxation and vasodilation in the lungs

51
Q

GPRCs are molecular

A

switches

On = bound to GTP
Off = bound to GDP

GTPases

52
Q

GPRCs are coupled to

A

a heterotrimeric subunit

53
Q

which part of the heterotrimeric subunit binds GTP/GDP

A

the a part

54
Q

in GPRCs what amplifies the signal

A

second messengers - eg cAMP

55
Q

how do B adrenergic receptors in heart, skeletal and lungs work

A

G protein receives signal, Gas dissociates from the other 2 when bound to GTP, stimulates adenylate cyclase to convert ATP to cAMP very quickly, which then activated PKA which will phosphorylate target proteins

56
Q

what is so beneficial about second messengers

A

small , produced rapidly , produce lots cellular response

57
Q

what do kinases do?

A

add phosphates to things

58
Q

what do specific Specific serine/ threonine/ tyrosine residues do?

A

regulate activity and localisation

59
Q

what is the chemical formulation of phosphate?

A

PO4

60
Q

what do beta blockers do?

A

heart conditions, high blood pressure combating

61
Q

what is an example of B adregenergic receptor antagonist

A

propanolol

62
Q

what do B antagonists end in

A

-olol

63
Q

what is a B antagonist in the lungs - for asthma

A

salbutamol

64
Q

what turns off the signal in the in Gas

A

phosphodiesterase

converts cAMP back to AMP

65
Q

which phosphodiesterase inhibitor is used to treat heart failure? how does this work?

A

PDE 3 inhibitor

increase the amount of cAMP

66
Q

how does the Kinase linked receptor work?

A

Outside portions bind – dimerise – brings kinases domains close together – phosphorylate one another
Lots molecules in cell – recognise phophorylated target site – recruitment to receptor – turn on G protein
This G protein is called ras

67
Q

what is ras?

A

a small GTPase

68
Q

in the kinase linked receptor what is the purpose of Ras?

A

induce a MAP cascade then the Pi binds to transcription factor (transcription factors are phosphorylated) and then move into the nucleus

69
Q

what is the function of perception in cancer?

A

stops EGF binding to its tyrosine kinase receptor - so the to receptors cannot phosphorylate one another - cannot promote growth inside the

70
Q

what would you use if you had a mutation in Ras so that you cannot turn it off?

A

inhibitor that block MAP kinase function

71
Q

how does PKA affect cardiac muscle?

A

phosphorylates L type calcium channel - Ca2+ flows in and then myosin chains contract, muscle contraction.