Cell communication

Question 1

What are the two different types of local signalling and give examples.

Answer 1

1. Paracrine signalling which occurs on nearby cells (fibroblast growth factor)
2. Synaptic signalling which occurs in the nervous system (Neurotransmitter called acetylcholine).

Question 2

Give an example of an endocrine cell signalling

Answer 2

Endocrine cell signalling is a type of long distance cell signalling, where insulin (hormone) travels to other organs to regulate blood glucose.

Question 3

What are the different types of membrane bound receptors and what does it mean to be membrane bound?

Answer 3

GPCR, Receptor Tyrosine Kinase, ligand-gated ion channel and it means these receptors are on the outer surface of the cell’s membrane. This is so they receive signals from outside the cell (water-soluble molecules) as these molecules can’t go inside.

Question 4

How many times can a GPCR weave in and out of the cell membrane?

Answer 4

7 times

Question 5

At what stage in cell signalling does the enzyme activate?

Answer 5

The enzyme becomes activated once the G protein binds to it.

Question 6

What lets the G protein to bind to the GPCR?

Answer 6

The change of shape of the GPCR (Conformational change).

Question 7

Explain the steps of ligand gated ion channels.

Answer 7

1. A ligand will bind to the ligand gated ion channel receptor on a specific site
2. As the binding occur, it will change the shape of the ligand gated ion channel which will trigger the opening and closing of the gate.
3. Specific ions can pass through now.

Question 8

Which body system relies heavily on ligand gated ion channels?

Answer 8

The nervous system:
– released neurotransmitters bind as ligands to ion channels on
target cells to propagate action potentials

Question 9

Why type of toxin disrupts the cAMP pathway?

Answer 9

Cholera toxin

Question 10

Where are calcium ions in high concentration and in low concentration?

Answer 10

1. High would be ER
2. Low would be cytosol