This set of Biochemistry MCQs focuses on “Sensory Transduction in Vision, Olfaction and Gustation”.
1. The G protein involved in visual signal transduction is
b) GTP receptor
Explanation: Rhodopsin is involved in visual signal transduction.
2. Cholera toxin is not a/an
a) Enzyme inhibitor
b) Enzyme activator
c) Enzyme modifier
d) Toxin released from bacteria in the infected intestine
Explanation: Cholera toxin is released from bacteria in the infected intestine. It inhibits the stimulation of cAMP synthesis.
3. In cholera there is uncontrolled secretion of
a) Na+ and H2O
b) K+ and H2O
c) Ca+2 and H2O
d) Mg+2 and H2O
Explanation: There is an uncontrolled secretion of Na+ and H2O in the intestine.
4. Vision, olfaction and gustation employ
a) Serpentine receptors
b) Enzyme coupled receptors
c) Ligand gated receptors
d) Adhesion receptors
Explanation: Serpentine receptors play an important role in rhodopsins, visual sense, olfaction and gustation.
5. Which out of the following statements about sense of smell is not true?
a) Olfactory receptor cells are bipolar neurons, not replaced when damaged
b) The chemicals are received by specific plasma membrane receptors in olfactory receptor cells
c) Olfactory receptors do not adapt quickly
d) The main areas of brain that interpret sense of smell be in the temporal and frontal lobes
Explanation: Olfactory receptors adapt quickly, the odor seems to be less powerful after a few minutes of exposure.
6. Most olfactory receptors are located on the
a) Superior surface of nasal cavity
b) Interior surface of nasal cavity
c) Lateral surface of nasal cavity
d) Medial surface of nasal cavity
Explanation: Most olfactory receptors are located on the superior surface of nasal cavity.
7. Objects are perceived by photo receptors because rods or cones
Explanation: The objects are perceived by photo receptors because rods or cones hyperpolarize as their pigments may decompose in presence of light.
8. Which of the following statements is not true about olfactory neurons?
a) Axons of olfactory neurons combine to form olfactory nerves
b) They synapse with cells in olfactory bulb
c) They have receptors that react with odorants dissolved in fluid
d) They are uni-polar neurons
Explanation: Olfactory neurons are bipolar neurons.
9. What is the relationship between olfactory sensors and gustatory sensors?
a) Gustatory hair can also detect odorants
b) Olfactory hair can also detect tastants
c) Olfactory sensors provides information about substance that we are about to taste
d) No relation
Explanation: The taste of food is partially due to food molecules stimulating olfactory receptors in the nose other than gustatory sensors in the mouth.
10. When visual stimulus reaches receptors in retina of eye, first process involving absorption of physical energy by receptors is
Explanation: Reception is the first process involved in the absorption of physical energy by receptors when visual stimulus reaches receptors in retina of eye.
11. When visual stimulus reaches receptors in retina of eye, second process involving absorption of physical energy by receptors is
Explanation: Transduction is the second process involved in the absorption of physical energy by receptors when visual stimulus reaches receptors in retina of eye.
Sanfoundry Global Education & Learning Series – Biochemistry.
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