cell signalling

Question 1

Three structural classes of hormones

Answer 1

1) peptide/ protein: bind to cell surface receptor
2) steroid: transported by carrier protein
3) amino acid (fatty acid deritvitive)

Question 2

4 types of cell signalling
1) endocrine e..g insulin
2) paracrine e.g. somatostatin
3) autocrine e.g. neurotransmitters
4)membrane protein contact e.g. T cells in immune system

Answer 2

1) hormone secreted into blood stream
2) shorter range. signalling molecule released short proximity to target cell
3) very short range on self
4) signalling cells interact with ‘receptor’ proteins on target cell. direct contact

Question 3

types of receptors
1) ligand gated ion channel (inotrophic receptors)
-what it’s expressed on

Answer 3

-electrically exitable cells e.g nerve and muscle

Question 4

2) G protein coupled receptor ( most common)
metabotropic receptor
-how many transmembrane spanning regions
-how it works to stimulate or inhibit receptor
e.g. adenlate cyclase pathway, ADH

Answer 4

-7 transmembrane
-whether a receptor is inhibitor or stimulatory depends on protein it interacts with
GPCR coupled to Gi inhibits their target
GPCR coupled to Gs stimulates their target

Question 5

3) kinase linked receptor
(large and diverse membrane receptor)
-what does it consist of

Answer 5

-extracellular ligand binding domain
-single transmembrane helix
-intracellular domain (enzymatic)

Question 6

4) nuclear receptor
-two different classes
class 1- present in cytoplasm
class 2- present in nucleas

examples

(only receptor that works intracellulry, the rest work cellular membrane)

Answer 6

class 1- their ligands are endocrine in nature eg. steroid hormone (cortisol)
class 2- their ligands are lipids e.g. fatty acids. difficult for molecules to enter and exit as requires a carrier protein

examples= cortisol, estrogen, thyroid hormones

Question 7

what receptor mediated response occurs the fastest

Answer 7

G protein coupled receptor via secondary messengers like cAMP