Cell Signalling Pathways

Question 1

How are cell signals classified

Answer 1

The distance they travel

Question 2

What are the 3 types of cell signals

Answer 2

Auto rinse, Paracrine, Endocrine

Question 3

What are autocrine signals

Answer 3

Signals that act on the same cell that secretes them

Question 4

What are paracrine signals

Answer 4

They bind to receptors on nearby cells

Question 5

What are endocrine signals

Answer 5

Hormones secreted by cells which target specific farther away cells

Question 6

What are the 2 types of cell signalling chemicals

Answer 6

Hydrophobic and hydrophilic

Question 7

What are hydrophobic signalling chemicals brought to the cell by? And why can they not do it by themselves

Answer 7

Carrier proteins, and because they cannot stay freely in the ECM

Question 8

Where do hydrophilic cell signals bind to? And why that site?

Answer 8

Receptors on the cells surface. Because they cannot pass through the cell membrane

Question 9

What are the 3 stages of cell signalling

Answer 9

Reception, transduction, response

Question 10

What are the main types of cell signal receptors

Answer 10

G-protein coupled receptor, nuclear receptor, ion channel receptor, enzyme coupled receptors

Question 11

What is the structure of G-proteins coupled receptors

Answer 11

Seven-pass transmembrane receptor and a G-protein

Question 12

What 3 subunits is the G protein made

Answer 12

Alpha, beta, gamma

Question 13

What molecule is the alpha subunit of G-protein bound to when it is dis activated

Answer 13

GDP

Question 14

What happens when a ligand binds to the receptor of G-coupled receptor

Answer 14

The alpha subunit leaves the G-protein. This causes GDP to be exchanged for GTP. The alpha subunit then exerts an influence on another protein. After doing this, it recombines with the G-protein and GTP is hydrolysed to GDP, disactivating the G-protein

Question 15

What type of molecule are cell-signals

Answer 15

Ligands

Question 16

What does adrenaline binding to the b2-adrenoreceptor cause

Answer 16

Bronchodilation

Question 17

What happens when adrenaline binds to the a1 receptor

Answer 17

Vasoconstriction of blood vessels

Question 18

What happens when adrenaline binds to the a1 receptor

Answer 18

Vasoconstriction of blood vessels

Question 19

What happens when adrenaline binds to the a2 receptor

Answer 19

Relaxation of GI tract

Question 20

What happens when adrenaline binds to the b1 receptor

Answer 20

Increased heart rate and cardiac muscle contraction

Question 21

What happens when adrenaline binds to the b3 receptor

Answer 21

Thermogenesis in skeletal muscle

Question 22

What drug is used to treat acute cases of bronchoconstriction

Answer 22

Salbutamol

Question 23

Why is adrenaline not a suitable drug for acute asthma attacks

Answer 23

The adrenaline would binds to all adrenoreceptors, causing a wide range of side effects

Question 24

What is the treatment given for chronic bronchoconstriction issues

Answer 24

Theophyline

Question 25

What is the structure of enzyme coupled receptors

Answer 25

2 domains, one receptor and one enzyme domain

Question 26

What enzyme is usually at the enzyme domain of an enzyme-coupled receptor

Answer 26

Kinase

Question 27

Why do enzyme coupled receptors form dimers

Answer 27

Because they can’t phosphorylate their own tyrosine. So they dimerise and cross-phosphorylate each other

Question 28

What does cross-phosphorylation cause in enzyme coupled receptors

Answer 28

An increase in affinity for their binding sites

Question 29

How do ligand-gated ion channels work

Answer 29

Ligand binds to the receptor opening the channel, ions can then flor through

Question 30

What do ligand-gated ion channels modulate

Answer 30

Fast synaptic excitation

Question 31

Where are nuclear receptors normally found

Answer 31

In the nucleus of target cell, bound by steroid hormones

Question 32

What 2 domains do nuclear receptors contain

Answer 32

Ligand binding domain and dna binding domain

Question 33

What does activation of nuclear receptors cause

Answer 33

The transcription of key proteins

Question 34

What is the nicotinic acetylcholine receptor an example of

Answer 34

A ligand gated ion channel

Question 35

What drug is useful for helping nicotine and why

Answer 35

Varenicline, because it is a partial agonist so can act antagonistically when paired with nicotine

Question 36

What is the insulin receptor an example of

Answer 36

An enzyme-linked receptor

Question 37

How many pathways can an enzyme-linked receptor lead to

Answer 37

Multiple

Question 38

How many pathways can a g-protein associated receptor bind to

Answer 38

1

Question 39

What feature of G proteins makes them have a large tissue response

Answer 39

Signal amplification