Cell_Signalling

Question 1

What is a G protein

Answer 1

Cell - surface receptors are coupled to trimeric (3 subunits) signal - transducing G proteins that bind either GTP or GDP.

Question 2

How does a G protein work

Answer 2

Ligand binding to G protein receptor activates it therefore inhibiting an enzyme to generate an intracellular second message.

Question 3

How many coupled receptors does a G-protein have

Answer 3

7 membrane spanning regions with their amino termini on the extracellular face and carboxy termini on the cytoplasmic face of the plasma membrane.

Question 4

Name four type of cell signalling

Answer 4

Endocrine - Hormone secretion from a gland into bloodstream to target cells
Paracrine signalling - Secretory cell - Adjacent target cell (e.g. Neurotransmission)
Autocrine - Cell signals to itself
Signalling by plasma membrane attachment )e.g. T cells in the immune system