cell signalling part 2

Question 1

What is a receiver?

Answer 1

Ligand binding region of receptor

Question 2

What is a transducer?

Answer 2

Conformational change of the receptor

Question 3

What is an amplifier?

Answer 3

Increase number of molecules affected by signal

Question 4

What is the responder?

Answer 4

Molecular function that change in response to signal

Question 5

Types of Receptors:

Intracellular

Answer 5

Binds to hydrophobic ligands

Question 6

Types of Receptors:

Ligand gated ion channels

Answer 6

Leads to changes in membrane potential

Question 7

Types of Receptors:

Receptor- enzymes

Answer 7

Lead to changes in intracellular enzyme activity

Question 8

Types of Receptors:

G-protein-coupled activation leads to what?

Answer 8

Activation of membrane-bound G-proteins

leads to changes in cell activity

Question 9

What are the steroid hormones derived from?

Answer 9

Cholesterol

Question 10

Three major types of steroid hormones:

The reproductive hormones (3)

The mineral-corticoid (1)

The Glucocorticoid (2)

Answer 10

1) Progesterone, testosterone, Estrogen

2) Aldosterone
- ion and salt regulation

3) Cortisol, corticosterone
- fear and stress response

** all of these are hydrophobic so dont need vesicles can go through membrane

Question 11

What are the 5 steps for intracellular receptors?

Answer 11

1. ligan diffuse across cell membrane
2. bind to receptor in cytoplasm or nucleus
3. L-R complex binds to specific DNA sequences
4. Regulates the Transcription of target genes
5. increase or decrease production of specific mRNA

Question 12

Receptor Enzymes:
characteristics
how do they sit in the membrane, what do they bind to?

Answer 12

Transmembrane

hydrophilic chemical mesangers

Question 13

Receptor Enzymes:

what does the catalytic domain of receptor star?

Answer 13

a phosphorylation cascade

phosphorylation of specific intracellular proteins

Question 14

Receptor tyrosine kinase:

in humans how many different types?

Answer 14

60

Question 15

Receptor tyrosine kinase:

what are SH2 regions

Answer 15

region where other signalling proteins will attach and is able to recognize

Question 16

Receptor tyrosine kinase:

how are they activated

Answer 16

via cross- phosphorylation by activated kinase domain

Question 17

Receptor tyrosine kinase:

the cytoplasmic RTKs have what type intrinsic activity

Answer 17

tyrosine kinase

Question 18

Receptor tyrosine kinase:

ligand binds to receptor and induces what?

Answer 18

dimerization and tyrosine trans autophosphorylation of both RTK subunits

Question 19

Receptor tyrosine kinase:

examples of RTKs? 3

Answer 19

insulin receptors, Trk receptors, BDNF or nerve factor receptors

Question 20

Receptor serine/threonine kinase:

how is this activated?

Answer 20

upon dimerization by a dimer ligand transforming growth factor (TGF-beta)

Question 21

Receptor serine/ Theronin kinase:

what does its intracellular domain have?

Answer 21

Intrinsic serine/threonine kinase enzyme activity

Question 22

Receptor serine/ Theronin kinase:

what does s the downstream effect?

Answer 22

SMAD proteins are phosphorylated translocated to nucleus regulates gene expression

Question 23

Receptor Guanylyl cyclase:

What does it regulate?

Answer 23

Atrial natriuretic peptide

regulates ECF volume and blood pressure

Question 24

Receptor Guanylyl cyclase:

what does it convert?

Answer 24

GTP to cyclic GMP

Question 25

Receptor Guanylyl cyclase:

What does it activate?

Answer 25

cGMP activates protein kinase G (PKG)

Question 26

Receptor Guanylyl cyclase:

What does PKG do?

Answer 26

phosphorylates target proteins and relaxes smooth muscles

lowers blood pressure by vasodilation