Receptors and modes of cellular communication

Question 1

What are the 4 main ‘super families’ of receptors?

Answer 1

Ligand- gated ion channels, G-protein coupled receptors, Kinase-linked receptors, Nuclear Receptors

Question 2

What is an example of a Ligand-gated ion channel?

Answer 2

Nicotinic ACh receptor

Question 3

What is an example of G-protein coupled receptor?

Answer 3

Muscarinic ACh receptor

Question 4

What is an example of a Kinase-linked receptor?

Answer 4

Cytokine receptors

Question 5

What is an example of a Nuclear receptor?

Answer 5

Oestrogen receptor , steriod receptor

Question 6

What is the time scale for each receptor in the 4 super families?

Answer 6

Ligand- Milliseconds
G-protein- Seconds
Kinase-linked- Hours
Nuclear- Hours

Question 7

What is an endogenous agonist?

Answer 7

Compound naturally produced by the body which binds to and activates that receptor

Question 8

What is an endogenous ligand?

Answer 8

Naturally occurring small molecules that bind to receptors- neurotransmitters, hormones, growth factors

Question 9

What is the structure of a ligand-gated ion channel?

Answer 9

Ion channel with multiple protein subunits

Question 10

Activation of GalphaS coupled receptors results in an inhibition of adenylyl cyclase. T or F?

Answer 10

False

Question 11

Endocrine regulation requires release of hormones into what system?

Answer 11

Circulatory system

Question 12

Adrenaline is a (1) if released during synaptic transmission and a
(2) if released into blood circulation.

Answer 12

1) Neurotransmitter

2) Hormone

Question 13

Somatostatin release from D cells binding to somatostatin receptor on D cells is example of what cellular communication?

Answer 13

Autocrine

Question 14

What is paracrine regulation?

Answer 14

Where signalling molecules are secreted into the extracellular space and bind to receptors located on adjacent cells, without passing through the circulatory system

Question 15

What are 4 modes of cell communication?

Answer 15

Autocrine, Paracrine, Endocrine, Synaptic Transmission

Question 16

What mode of cell communication acts as a negative feedback loop?

Answer 16

Autocrine

Question 17

Parasympathetic and sympathetic responses both maintain the body’s homeostasis but what are the differences?

Answer 17

Parasympathetic- Returning body to routine

Sympathetic- Involved in preparing the body for stress-related activities

Question 18

What do enterochromaffin cells secrete?

Answer 18

Histamine

Question 19

What is the difference between Paracrine and Endocrine regulation?

Answer 19

Endocrine requires the circulatory system.

Paracrine- Cells are regulating or communicating with cells next door

Question 20

What area is synaptic transmission specific to?

Answer 20

The Nervous System

Question 21

What is a neurotransmitter?

Answer 21

Chemical substance released from a neuron and bringing about the transfer of an impulse to another neuron

Question 22

Why can some neurotransmitters be hormones?

Answer 22

Depends on mode of communication

Question 23

Examples of neurotransmitters

Answer 23

Acetylcholine, Adrenaline, Dopamine, Histamine

Question 24

Salbutonal activates what type of receptors that results in brochodilation?

Answer 24

beta2 adrenoreceptors

Question 25

G-protein receptors consist of how many loops in their structure? What nucleotides bind to them when they are active and inactive?

Answer 25

7
Active- GTP
Inactive- GDP

Question 26

GPCRs are heterotrimeric (three different subunits), what are they and what 2 are attached to the plasma membrane by lipid anchors?

Answer 26

Alpha, beta, gamma

Alpha and gamma are attached to plasma membrane

Question 27

When a signalling molecule binds to GPCR what do the two protein subunits consist of when they dissaccociate?

Answer 27

GTP- alpha subunit

beta-gamma dimer

Question 28

What is a common enzyme activated by G-proteins that goes on to catalyze of synthesis of cAMP from ATP which is involved in responses to sensory input, hormones, nerve transmission etc.

Answer 28

Adenylyl cyclase