The vitamin that is required for the formation of the visual pigment rhodopsin is: MCQ with Answer and Explanation

The vitamin that is required for the formation of the visual pigment rhodopsin is:
A. Vitamin C
B. Vitamin D
C. Vitamin B₁
D. Vitamin A
Answer: Option D
Solution (By JKSSB Mock Tests)
Vitamin A (retinal) combines with opsin to form rhodopsin in rod cells, necessary for vision in dim light. Deficiency causes night blindness. B₁ is for carbohydrate metabolism, C for collagen, D for calcium.

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The organelle that contains enzymes for intracellular digestion is the:
A. Mitochondria
B. Lysosome
C. Chloroplast
D. Peroxisome

Correct Answer: Option B


Explanation:
Lysosomes are membrane-bound vesicles packed with hydrolytic enzymes (proteases, lipases, nucleases) that digest macromolecules, old organelles, and engulfed pathogens. They maintain an acidic pH (about 5.0) for optimal enzyme activity. Peroxisomes detoxify peroxides, mitochondria generate ATP, chloroplasts perform photosynthesis.

This question belongs to: Science Biology
Question #2
The scientist who discovered the bacterium Helicobacter pylori and its role in ulcers was:
A. Louis Pasteur
B. Robert Koch
C. Alexander Fleming
D. Barry Marshall and Robin Warren

Correct Answer: Option D


Explanation:
Marshall and Warren discovered H. pylori in 1982 and proved it causes peptic ulcers, earning the 2005 Nobel Prize. Koch discovered TB, Pasteur vaccines, Fleming penicillin.

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Question #3
The enzyme that breaks down acetylcholine in the synaptic cleft is:
A. Catechol-O-methyltransferase
B. Monoamine oxidase
C. Acetylcholinesterase
D. Choline acetyltransferase

Correct Answer: Option C


Explanation:
Acetylcholinesterase degrades acetylcholine into acetate and choline, terminating the synaptic signal. Choline acetyltransferase synthesizes ACh, MAO and COMT degrade monoamines.

This question belongs to: Science Biology