Receptors 1

Question 1

what is a receptor?

Answer 1

the term denotes the component of the organism with which the chemical agent is presumed to interact

Question 2

what is the majority of drug target?

Answer 2

receptors are the majority of drug targets

Question 3

what are the majority of receptors?

Answer 3

proteins 24% enzymes 9% voltage gated ion channels 8% membrane transporters 12% other

Question 4

how would you describe the primary structure of a protein?

Answer 4

the amino acid sequence of the polypeptide chain

Question 5

how is a peptide bond formed between two amino acids?

Answer 5

through a condensation reaction

Question 6

what are the secondary structures of protein?

Answer 6

alpha helix and beta pleated sheet

Question 7

what is the tertiary structure of proteins?

Answer 7

Three-dimensional structure of a peptide, results from hydrophobic and hydrophilic interactions between residues far apart on the chain. Disulfide bonds and hydrogen bonds can also add to the tertiary structure of the protein.

Question 8

What is the quatenary structure of a protein?

Answer 8

consists of two or more polypeptide chains or subunits. “Higher order of peptide come together to form multi subunit”

Question 9

what is β2AR-Gs?

Answer 9

gene protein

Question 10

What is β2AR-Nb80?

Answer 10

antibody

Question 11

What is the β-adrenergic receptor?

Answer 11

it is a protein

Question 12

intracellular receptors

Answer 12

receptors located inside the cell rather than on its cell membrane ex: Steroid R

Question 13

receptor tyrosine kinases

Answer 13

membrane receptors that attach phosphates to tyrosines Ex: Growth Factor R

Question 14

Ligand-gated Ion Channels

Answer 14

Ion channels that respond to chemical signals rather than to the changes in membrane potential generated by ionic gradients. The term covers a large group of neurotransmitter receptors that combine receptor and ion channel functions into a single molecule. The signal binds to and directly regulates the opening of an ion channel Ex: Nicotinic AChR

Question 15

G protein-coupled Receptors

Answer 15

the signal binds to a cell-surface receptor linked to an effector enzyme by a G protein. Ex: Adrenergic R, Muscarinic AChR

Question 16

what is the mechanism of α-Bungarotoxin neurotoxin?

Answer 16

it binds to nicotinic AChR tenaciously and blocks the receptor.

Question 17

What happens if someone is exposed to snake venom with the α-Bungarotoxin neurotoxin?

Answer 17

paralysis aka lack of muscle contraction

Question 18

What is the mechanism of Epibatidine?

Answer 18

it binds to nicotinic AChR very tightly and activates the receptor

Question 19

What will happen if someone is exposed to the toxin Epibatidine?

Answer 19

They would experience uncontrollable movement, contractions and eventually paralysis

Question 20

What do cell membranes potentials result from?

Answer 20

1. Uneven distribution of ions across the membrane
2. selective permeability of different ions

Question 21

At resting potential what is there a lot more of? how much?

Answer 21

there are about ten times more open K+ channels than open Na+ and Cl- channels

Question 22

What is the consequence of more K+ channels being open?

Answer 22

more positively K+ ions exit the cell. than Na+ and Cl- ions enter, and the outside plasma membrane acquires a net positive charge relative to the inside.

Question 23

What leads to depolarization?

Answer 23

opening of nAChR leads to influx of sodium ions

Question 24

what happens when the membrane potential depolarizes above a threshold level?

Answer 24

voltage-sensitive Na+ channels are triggered to open causing more Na+ influx which initiate the action potential

Question 25

What is the mechanism of the toxin tetrodotoxin?

Answer 25

it can bind to and block voltage-sensitve sodium channels.

Question 26

what happens when someone is exposed to tetrodotoxin?

Answer 26

lack of cell depolarization and then paralysis.