Cell signalling

Question 1

What is the purpose of steroids?

Answer 1

They can alter DNA in cells so are able to get into cells very easily

Question 2

What is cell signalling?

Answer 2

Communication between cells that allows effective coordination of a response

Question 3

How are cell signals transferred only to certain cells?

Answer 3

Only target cells have the specific receptor to the ligand

Question 4

How does cell signalling work?

Answer 4

1. A sending cell sends a ligand which is complimentary to a specific intrinsic receptor protein on the binding site of the target cell.
2. Specific messenger molecule binds to a specific receptor glycoprotein and its complementary in shape.
3. This causes a response inside the cell and an enzyme produces a second messenger molecule.

Question 5

What is an example of a second messenger molecule?

Answer 5

Cyclic AMP

Question 6

What is the result of cell signalling?

Answer 6

There is a change in the gene expression and the cell makes different proteins or enzymes and behaves differently

Question 7

What are ways the chemical can reach the target cell?

Answer 7

Endocrine (blood), paracrine, neuronal and contact dependant

Question 8

What are the 4 effects of adrenaline?

Answer 8

Increased heart rate, increased diameter of bronchioles, dilated pupils and inhibited gut action

Question 9

Why does adrenaline increase heart rate?

Answer 9

More blood and more oxygen are being moved around so faster delivery of oxygen and glucose

Question 10

Why does adrenaline increase the diameter of bronchioles?

Answer 10

More air can be taken in so more oxygen can be taken in and delivered to muscles

Question 11

Why does adrenaline dilate pupils?

Answer 11

More light comes in so you can see better

Question 12

Why does adrenaline inhibit gut action?

Answer 12

You can be faster as less is happening

Question 13

What is an example of endocrine signalling?

Answer 13

When blood sugar levels are high, pancreas cels release insulin, causing the uptake of glucose and polymerisation to glycogen

Question 14

How is histamine an example of paracrine signalling?

Answer 14

Histamine is released by infected cells which dilates capillaries and attracts neutrophils, resulting in more plasma, swelling and redness

Question 15

What are 2 examples of paracrine signalling?

Answer 15

Histamine released by infected cells and T-helper cells

Question 16

How are T-helper cells an example of paracrine signalling?

Answer 16

They release cytokines which are involved in growth diffusion, and it is local lease as act over a short distance at a low concentration to assist B-lymphocytes become B-plasma cells and B-memory cells

Question 17

What is an example of neuronal signalling?

Answer 17

Nerve cells use electrical signals along their length and the synapse releases vesicles of neurotransmitter by exocytosis

Question 18

What is an example of contact-depends signalling?

Answer 18

Macrophages present antigens to circulating B- and T-lymphocytes and only those with specific receptor will bind and be clonally selected