Brainscape's Knowledge GenomeTM

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


See full index

MBB161 > Gray (Cell signalling and communication) > Flashcards

Gray (Cell signalling and communication) Flashcards

1
Q

Do all cells communicate?

A
  • all communicate w/ each other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What signals do cells send and receive?

A
  • send and receive chem signals

- receive signal from env

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

Why do cells communicate?

A
  • coord activities to behave as group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many cells in human body

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

What is the pathway taken from signal to response?

A
  • signal
  • reception (and amplification)
  • transduction
  • response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is signal transduction?

A
  • info converted from 1 form to another
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What signalling molecules do cells use and why?

A
  • use variety (usually not involved in metabolic pathway)
  • eg. proteins, mod AAs, lipids
  • as quick to make and destroy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are signalling molecules released from signalling cell?

A
  • diffusion or exocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the types of 1st messengers or ligands?

A
  • hormones (long distance)
  • local mediators
  • neurotransmitters
  • contact dependent signals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What chemical signals do cells respond to?

A
  • 1st messengers or ligands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a signalling molecule/ligand?

A
  • small molecule that binds to site on macromolecule surface by intermolecular forces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens when ligand binds to receptor molecule?

A
  • changes specific receptor molecule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Types of intercellular signalling

A
  • endocrine
  • paracrine
  • neuronal (specific type of paracrine)
  • contact dependent signals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does endocrine signalling work?

A
  • signal molecule released (hormones)
  • collected and distributed via blood in animals
  • only cells w/ receptors respond
  • response depends on cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Examples of endocrine signalling (hormone, released from, type of molecule, effects)

A
  • adrenaline, released from adrenal gland, Tyr derivative. increases blood pressure, heart rate and metabolism
  • insulin, pancreas, protein, stimulates glucose uptake and synthesis of proteins and lipids
  • testosterone/oestrogen, testes/ovaries, steroid, induces and maintains 2º male/female sexual characteristics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does paracrine signalling work?

A
  • molecules released and responded to by neighbouring cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Examples of paracrine signalling (hormone, released from, type of molecule, effects)

A
  • epidermal growth factor, various cells, protein, stimulates epidermal and many other cell types to proliferate
  • histamine, mast cells, His derivative, blood vessel dilation and become leaky, helping cause inflammation
  • NO, cells lining blood vessels, dissolved gas, causes smooth muscle cells to relax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does neuronal signalling work?

A
  • neurons prod and release neurotransmitters into synapse, close to target cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Example of neuronal signalling (hormone, released from, type of molecule, effects)

A
  • ACh, nerve terminals, choline derivative, neurotransmitter at many nerve-muscle synapses and in CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Example of how the same signalling molecule can induce diff responses in diff target cells?

A
  • ACh
  • decrease freq contraction in cardiac muscle cells
  • secretion in salivary gland cells
  • contraction of skeletal muscle cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does contact dependent signalling work?

A
  • molecules of plasma membrane bind in specific ways

- eg. cell interactions in early dev

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

Example of contact dependent signalling (hormone, released from, type of molecule, effects)

A
  • delta, prospective neurons and various other embryonic cell types, transmembrane protein, inhibits neighbouring cell from becoming specialised in same way as signalling cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the flow of info during cell signalling?

A
  • receptor-ligand binding
  • signal transduction (via 2nd messenger)
  • cellular responses
  • changes in gene expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How can receptor proteins only respond to subset of signals surrounding them?

A
  • receptor-ligand interactions specific
  • signals cell can respond to determined by receptor proteins it has
  • ignore signals it doesn’t have receptor for
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Are all receptors enzymes?

A
  • all are proteins
  • some have enzyme activities
  • some affect enzymes indirectly
  • some affect gene expression
26
Q

What are receptor molecules?

A
  • signal transducers

- 3D shape

27
Q

What type of interaction occurs between receptor and ligands?

A
  • non-covalent
28
Q

What can receptor-ligand interactions cause?

A
  • may induce shape change in receptor protein

- results in intracellular response

29
Q

Do receptor molecules need to be high affinity and why?

A
  • yes as many concs are v low
30
Q

How are receptor protein genes grouped?

A
  • many grouped into families
31
Q

What is an orphan receptor protein gene?

A
  • when function is unknown
32
Q

In what way do cell surface receptors convert signals and how?

A
  • convert extracellular to intracellular signal

- by inducing change in cyto

33
Q

What are the 3 major classes of cell surface receptors?

A
  • ligand gated ion channels
  • receptors w/ enzyme activity
  • G-protein coupled receptors
34
Q

Where can receptors be located?

A
  • intracellular

- on cell surface

35
Q

What is an intracellular response?

A
  • signal passes through target cell plasma membrane
36
Q

How does an intracellular receptor w/ enzyme activity work, using the example of NO(g)?

A
  • NO binds to enzyme
  • activated enzyme catalyses synthesis of cyclic GMP
  • relaxes smooth muscle surrounding blood vessels
  • blood vessels expand, increasing blood flow
  • prod in endothelial cell lining blood vessel and diffuses into target cell
  • NO release by nerve terminals causes erection
37
Q

How does Viagra work?

A
  • inhibits cGMP conversion to GMP
38
Q

Example of an intracellular receptor regulating gene transcrip

A
  • steroid hormone receptor family
  • signal molecule binds to site on receptor
  • activated receptor complex enters nucleus
  • binds DNA and alters gene expression
39
Q

How do ligand gated ion channels work?

A
  • receptor is transmembrane protein
  • winds across plasma membrane several times
  • centre forms pore which ions can pass through
  • opens and closes when ligand bind to protein
40
Q

Example of a ligand gated ion channel

A
  • ACh receptor
41
Q

How do receptors w/ enzyme activity work?

A
  • single pass transmembrane protein
  • signal molecule binds outside cell, activating enzyme
  • part w/ enzyme activity in cyto
42
Q

What kind of enzyme are most receptors w/ enzyme activity, and what do they do?

A
  • most protein kinases and add phosphates to proteins
  • receptor kinases act as dimers
  • phosphorylation of AA side chains affects enzyme activity
  • can often activate other kinases –> cascade
43
Q

How are receptor kinases activated?

A
  • dimerisation and transphosphorylation
44
Q

How do G-protein coupled receptors work?

A
  • 7 pass receptors
  • ligand binding activates G-protein, causing it to bind GTP
  • activated G-protein diffuses away from receptor and affects activity of effector enzyme
45
Q

What class of cell surface receptors are involved in half the mechanisms of medicines in use?

A
  • G-protein coupled receptors
46
Q

What do G-protein coupled receptors mediate responses to?

A
  • diverse responses to hormones, local mediators and neurotransmitters
47
Q

In what senses are G-protein coupled receptors found?

A
  • odorant and vision receptors
48
Q

How does the receptor kinase downstream signalling pathway work?

A
  • ligand binding leads to receptor dimerisation
  • phosphorylation of cytosolic Tyr residue
  • other proteins recognise and bind Tyr
  • activates intracellular signalling pathways, eg. kinase cascades, 2nd messenger release
49
Q

What happens when the Ras GTPase switch is on?

A
  • GTP bound
  • receptor activation causes Ras to bind GTP
  • Ras-GTP activates specific kinases which activate kinase cascades
  • leading to cell proliferation
50
Q

What happens when the Ras GTPase switch is off?

A
  • GDP bound
  • Ras GTPase activity hydrolyses GTP
  • cascade req ATP
51
Q

What do signalling cascades result in?

A
  • amplification of response
52
Q

What are intracellular responses a response to?

A
  • receptor-ligand binding

- inc protein phosphorylation, Ca release, cAMP

53
Q

What do intracellular responses cause changes in?

A
  • enzyme activity
  • gene expression
  • cytoskeleton
54
Q

How does phospholipase C lead to release of Ca in intracellular response?

A
  • phospholipase C (PLC) activated by receptor (either G-protein coupled or receptor kinase)
  • phospholipase C cleaves membrane phospholipid to prod diacylglycerol (DAG) and inositol triphosphate (IP3)
  • IP3 is 2nd messenger and binds to receptors on internal membranes and releases Ca
55
Q

How does Ca2+ affect enzyme activity?

A
  • rushes into cyto when Ca channels opened
  • increasing conc affects Ca activated proteins, eg. calmodulin
  • activated calmodulin activates other proteins, inc kinases
56
Q

Why is Ca released on fertilisation?

A
  • trigger egg activation

- resumption of metabolic processes leading to embryo dev

57
Q

How do G-protein coupled receptors activate effector enzymes that prod 2nd messengers?

A
  • PLC catalyses IP3 prod
  • adenylate cyclase catalyses cAMP prod
  • PLC also activated by GPCRs, many GPCRs activate cAMP prod
58
Q

What are cAMPs mediated responses?

A
  • cAMP mainly acts by activating certain protein kinases

- in most cells boosts energy release

59
Q

What do signalling networks look like?

A
  • pathways interact

- not straight lines

60
Q

What can mutant forms of Ras do, and where is this found?

A
  • mutant forms of Ras can bind GTP but can’t hydrolyse it

- found in many human tumours

MBB161 (6 decks)

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