Debbie Hay -1

Question 1

What are the different types of signal?

Answer 1

Endocrine, paracrine, autocrine signals, direct cell-cell signalling

Question 2

What is endocrine signalling?

Answer 2

When a hormone is is released from a gland and travels through the blood to act on a distal target organ. E.g. insulin

Question 3

What is paracrine signalling?

Answer 3

When the signal is released from one cell to act on adjacent cells for example acetylcholine at the neuromuscular junction

Question 4

What is autocrine signalling?

Answer 4

Signals act on the same cell they are released from for example growth factors

Question 5

What is cell-cell signalling?

Answer 5

Occurs when the cells are in contact with each other for example T cell activation by surface proteins on antigen presenting cells

Question 6

What is the process of reception in signal transduction?

Answer 6

Signal is released following a stimulus binds to proteins on the surface of a cell called receptors, so it is not required to enter the cell
when the ligand interacts with the receptor it undergoes a conformational change

Question 7

What is transduction?

Answer 7

The passing of a signal though a cell which involves different chemicals such as second messengers

Question 8

Why are second messengers important?

Answer 8

While only a few receptors may be activated one receptor may produce several second
messengers allowing for signal amplification
Unlike the receptors they are not membrane bound and can diffuse throughout the cell to influence different proteins
Multiple receptors use common second messengers allowing for finely tuned regulation of cellular activity

Question 9

What are GCPRs?

Answer 9

G-Protein coupled receptors
Large family of genes (1% of human genome)
Each has a different extracellular structures so different ligands can be recognized
Have three major families of A,B and C
All have 7 transmembrane domains with Extracellular N-terminus and intracellular C-terminus