Brainscape's Knowledge GenomeTM

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


See full index

Lily PoM MBC > Cell Signalling > Flashcards

Cell Signalling Flashcards

1
Q

What are 4 reasons we need cell signalling?

A

To process information
When an outpost is required from an input it is important the the body can communicate to do this

For self preservation
Eg fight or flight

Voluntary movement
Involves a lot of different sensory and motor organs all coordinated by the brain

For homeostasis
Eg blood glucose or calcium levels

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

Which two systems in the body provide lines of communication?

A

Nerve fibres in the CNS and PNS

The blood vessels of the CVS

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

What is the difference between communication using nerves and the blood

A

Nerves
Faster
But simple information

Blood
Slower
But other substances can be transported

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

What is the first step in neurotransmission (across a synapse)?

A

Propagation of the action potential

Voltage gates sodium channels open

Na+ influx —> membrane depolarisation —> propagation of action potentials

VGKC opens —> K+ efflux —> repolarisation

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

What is the second step in neurotransmission (across a synapse)?

A

Neurotransmitter released from vesicles

Action potential opens voltage gates calcium channels at presynaptic Terminal

Ca2+ influx —> binds to vesicles —> neurotransmitter released into synaptic cleft (exocytosis)

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

What is the third step in neurotransmission (across a synapse)?

A

Activation of postaynaptic receptors

Neurotransmitters bind to receptors on post synaptic membrane

Modulates post synaptic activity

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

What is the fourth step in neurotransmission (across a synapse)?

A

Activation of post synaptic receptors

These can come in a variety of forms

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

What is the method of transfer of information in the blood?

A

Hormones

Released from glands such as the pituitary and the hypothalamus

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

What is endocrine signalling?

A

Hormones travel within the blood vessels to act on a distant target cell

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

Give an example of Endocrine communication

A

Hypoglycaemia

Glucagon secreted by a-cells in the islets of langerhans in the pancreas

Glucagon travels in the blood to liver

In the liver it stimulates glycogenolysis and gluconeogenesis increasing blood glucose levels

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

What is paracrine communication?

A

Hormones acting on adjacent cells

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

What is an example of paracrine communication?

A

Hyperglycaemia

Increased blood glucose
Insulin secretion by B-cells of pancreas

Paracrine effects are inhibiting glucagon secretion in adjacent a-cells

(Also has endocrine effects in the liver)

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

What is cell signalling between membrane attached proteins?

A

Plasma membrane proteins on adjacent cells interacting

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

What is an example of signalling between membrane attached proteins?

A

Immune reaponse

Blood borne virus (eg hep C ) enter blood

This is detected by an antigen presenting cell

APC digests pathogen and expresses major histo-compatability (MHC) class II molecules on surface

Circulating T lymphocyte engages with MHC molecule through T-cell receptor (TCR) interaction

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

What is autocrine signalling?

A

Signalling molecule acts in the same cell

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

What is an example of autocrine signalling?

A

Activated TCR initiates a cascade of reactions within the T cell

Activated T cell expresses interleukin-2 receptor on surface

Activated T cell also secretes IL-2
This binds to IL-2 receptor in same cell, as well as adjacent cells

17
Q

What are the four categories of receptors?

A

Ligand gated ion channel receptors (ionotropic receptors)

G protein coupled receptors

Enzyme linked receptors

Intracellular receptors

18
Q

What are some properties of ligand gated ion channel receptors?

A

Central pore incorporated into their quaternary structure

When the appropriate ligand attaches to the ‘ligand binding domain’ the pide opens

Eg nicotinic acetylcholine receptor binds acetylcholine ligand. This effects muscle contraction or cognitive enhancement

(Look at insendi for examples)

19
Q

How do ligand gated ion channels work?

A

Ligand binds to receptor protein

Change in confirmation of channel protein opens pore

Pore allows ions to move through depending on the direction of the concentration gradient

20
Q

What are G protein couples receptors?

A

Aka 7-transmembrane receptors

Linked to an intracellular G protein complex, consists of an alpha subunit, a beta-gamma subunit and an associated GDP molecule

21
Q

How do G protein coupled receptors work?

A

7-TM receptor and heterotrimeric G protein are inactive and un bound p

Ligand binds, conformation of receptor changes

G protein trimer and associated GDP bind to receptor

GDP is phosphorylated to GT

G protein dissociates into the alpha subunit (with GTP) and the By subunit. These big d to their target proteins and induce the desired effects

To inactivate:
Ligand unbinds

GTPase dephosphorylates GTP to GDP

Alpha subunit dissociates from target protein

Trimmer forms again

22
Q

What are enzyme linked receptors?

A

Only one transmembrane domain

This has a ligand binding domain on the outside and specialised enzymes (usually tiresome kinases) on the inside

They don’t usually work alone, require clustering of more than one receptor protein to activate enzyme

23
Q

How do enzyme linked receptors work?

A

Ligand binds, causes receptors to cluster together

Clustering activates anzyme activity in the cytoplasm

the enzymes phosphorylation the receptor

Phosphorylation leads to the binding of signalling proteins to cytoplasmic domain

Signalling proteins generate a cascade of effects within the cell

24
Q

What are intracellular receptors?

A

Steroid hormones are mambrane permeable (hydrophobic, lipophilic)

Therefore need intracellular receptors

These are essentially transcription factors, so regulate mRNA and protein synthesis

Two types. Type I, type II

25
Q

How do type I intracellular receptors work?

A

Cytoplasmic - located working the cytosolic compartment

Associated with chaperone molecules (heat shock proteins)

Hormone binds to receptor, causing hsp to dissociate

2 hormone bound receptors form a homodimer

This translocates to the nucleus, and binds to DNA

26
Q

How do type II intracellular receptors work?

A

Nuclear

Often already bound to DNA

Ligand binds to receptor in the nucleus

Leads to transcriptional regulation

Lily PoM MBC (15 decks)

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