9.2

Question 1

What does the response of a target cell to a signal molecule depend on?

Answer 1

Whether it has the specific receptor for that molecule

Question 2

Where are the receptors for hormones located?

Answer 2

• receptors in the cytosol
• receptor in the nucleus
• receptors on the surface of the cell membrane

Question 3

What is the difference between lipophillic signal molecules and lipophoic molecules?

Answer 3

Lipophilic cna diffuse through the cell membrane to the receptors in the cystic or bind to the surface receptors
lipophobic only bind to the receptors on the surface of the cell membrane

Question 4

What is the process of lipophobic hormones biding to the receptors?

Answer 4

Signal molecule binds to receptor protein
This activates intracellular signal molecules
This alters the target proteins
Which creates a response

Question 5

What are the different types of cell surface receptors?

Answer 5

Receptor channel
Receptor enzyme
G protein-coupled receptor
Integrin

Question 6

What happens at a receptor channel?

Answer 6

Ligand binding opens or closed the channel

Question 7

What happens at the receptor enzyme?

Answer 7

Ligand binding to a receptor-enzyme activates an intracellular enzyme

Question 8

What happens at the G protein-coupled receptor?

Answer 8

Ligand binding opens an ion channel or alters enzyme activity

Question 9

What happens at the integrin receptor?

Answer 9

Ligand binding to receptor alter the cytoskeleton

Question 10

What happens in signal amplification downstream of cell surface receptors

Answer 10

• Receptor-ligand complex activates an amplifier enzyme resulting in a single signal molecule turning on many second messengers.
• Adenylyl cyclase and phospholipase C are examples of amplifier enzymes.
• cAMP and IP3 are examples of second messenger molecules.
• These signals can produce responses in the target cell by altering the activity of enzymes, ion channels, transporters, genes, etc.

Question 11

What does response depend on?

Answer 11

Receptor type

Question 12

What can noradrenaline bind to?

Answer 12

Different isoforms of adrenergic receptors

Question 13

What can change depending on the type of receptor in blood vessels?

Answer 13

It can cause either dilation or constriction

Question 14

What do lipophillic hormones act primarily on?

Answer 14

Intracellular receptors

Question 15

What determines the response elicited by a hormone?

Answer 15

Amount of hormone in blood
Affinity between the receptor and hormone
Number of receptors
Up regulation and down regulation
Functionality of components downstream of the receptor