Cell signalling

Question 1

Modes of communication

Answer 1

• direct cell-cell signalling(really short distance)
• neurotransmitters-
• signaling by secreted molecules(long - distance)

Question 2

What is endocrine signalling

Answer 2

• signalling by secreted molecules

- where endocrine cells secrete hormones that are carried through the circulation to act on target cells

Question 3

What are the derivatives of cholesterol

Answer 3

• steroid hormones are derivatives of cholesterol

- the hydrophobic nature allows diffusion across membranes

Question 4

WHat happens in the presence of hormones in cell signalling

Answer 4

changes conformation of receptor, displacing HDAC (corepressor) for HAT (coactivator) that is bound to the thyroid hormone receptor

Question 5

What are thyroid hormones

Answer 5

non steroid chemical hormones that bind DNA in an inactive form that becomes active when bound with hormone

Question 6

Paracrine signalling

Answer 6

short distance communication mode in which molecule released by one cells acts on target cells

Question 7

what is Paracrine signalling

Answer 7

short distance communication mode (neurotransmitters) in which molecule released by one cells acts on target cells

Question 8

Neurotransmitters as paracrine ligands

Answer 8

• hydrophilic
• release stimulated by action potential in neuron
• bind cell surface receptors
• depolarization
• also bind G protein couples receptors

Question 9

Nitric acid as paracrine ligands

Answer 9

• difuses out of cell freely
• extremely unstable
• induction of NO synthesis in endothelial cells of blood vessels by release of acetylcholine from neurons
• diffusion of NO to surrounding smooth muscles

Question 10

what can limit a ligand’s effect on target cells

Answer 10

• chemical nature of ligand
• distance from target cell
• receptors on target cell
• intercellular molecules