Physiology Q6

Question 1

Where are odorants detected in the nose?
o A) Nasal septum
o B) Main olfactory epithelium
o C) Nasal conchae
o D) Nasal vestibule

Answer 1

B) Main olfactory epithelium

Question 2

What happens when an odorant binds to an olfactory receptor?
o A) It activates a G protein-coupled receptor signaling pathway
o B) It directly opens ion channels
o C) It inhibits adenyl cyclase
o D) It decreases cAMP levels

Answer 2

A) It activates a G protein-coupled receptor signaling pathway

Question 3

Which type of photoreceptor cells are responsible for bright light and color
vision?
o A) Rods
o B) Cones
o C) Bipolar cells
o D) Ganglion cells

Answer 3

B) Cones

Question 4

What is the role of rhodopsin in rod cells?
o A) It absorbs light and initiates a signaling pathway
o B) It releases neurotransmitters
o C) It directly opens ion channels
o D) It inhibits cGMP phosphodiesterase

Answer 4

A) It absorbs light and initiates a signaling pathway

Question 5

What happens to cGMP levels in rod cells in the dark?
o A) They increase
o B) They decrease
o C) They remain unchanged
o D) They fluctuate

Answer 5

A) They increase

Question 6

Which protein binds to phosphorylated rhodopsin to prevent further activation?
o A) Transducin
o B) Arrestin
o C) Adenyl cyclase
o D) Guanylate cyclase

Answer 6

B) Arrestin

Question 7

What is the main function of cones in the visual system?
o A) Function in dim light
o B) Perceive color
o C) Detect motion
o D) Respond to a single photon

Answer 7

B) Perceive color

Question 8

Which enzyme synthesizes cGMP from GTP?
o A) Adenyl cyclase
o B) Guanylate cyclase
o C) Phosphodiesterase
o D) Rhodopsin kinase

Answer 8

B) Guanylate cyclase

Question 9

What is the effect of hyperpolarization in rod cells?
o A) It inhibits bipolar cells
o B) It depolarizes bipolar cells
o C) It increases glutamate release
o D) It closes cGMP-gated ion channels

Answer 9

B) It depolarizes bipolar cells

Question 10

What happens to rhodopsin in the presence of light?
o A) It becomes phosphorylated
o B) It releases glutamate
o C) It activates cGMP phosphodiesterase
o D) It increases cGMP levels

Answer 10

C) It activates cGMP phosphodiesterase

Question 11

What is the role of cAMP in olfactory signaling?
o A) It inhibits adenyl cyclase
o B) It activates cAMP-gated ion channels
o C) It decreases intracellular Ca2+ levels
o D) It closes Na+ channels

Answer 11

B) It activates cAMP-gated ion channels

Question 12

What type of protein receptors are involved in detecting odorants?
o A) Ion channels
o B) G protein-coupled receptors
o C) Tyrosine kinase receptors
o D) Ligand-gated ion channels

Answer 12

B) G protein-coupled receptors

Question 13

What ions influx to depolarize the neuronal membrane in olfactory signaling?
o A) K+ and Cl-
o B) Na+ and Ca2+
o C) H+ and OH-
o D) Mg2+ and SO4^2-

Answer 13

B) Na+ and Ca2+

Question 14

What allows a small array of receptors to distinguish a vast number of
odorants?
o A) Each receptor binds to a single odorant
o B) Each odorant activates a unique combination of receptors
o C) Each receptor binds to multiple odorants
o D) Each odorant activates all receptors equally

Answer 14

B) Each odorant activates a unique combination of receptors

Question 15

What creates a spatial map of odorant-responsive neuronal activity within the
olfactory bulb?
o A) The random distribution of neurons
o B) The specific sites in the brain linked to neurons expressing specific ORs
o C) The uniform distribution of odorant receptors
o D) The random activation of neurons

Answer 15

B) The specific sites in the brain linked to neurons expressing specific ORs