Which of the following is the primary product of the light-dependent reactions of photosynthesis? MCQ with Answer and Explanation

Which of the following is the primary product of the light-dependent reactions of photosynthesis?
A. Water
B. ATP and NADPH
C. Oxygen only
D. Glucose
Answer: Option B
Solution (By JKSSB Mock Tests)
Light reactions occur in the thylakoid membranes, converting light energy into chemical energy in the form of ATP and NADPH, with oxygen as a by-product. These energy-rich molecules are used in the Calvin cycle (light-independent reactions) to fix CO₂ into carbohydrates. Glucose is a final product of the Calvin cycle. Oxygen is released but not the primary product. Thus ATP and NADPH are the main outputs.

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Question #1
The type of reproduction that involves only one parent and no gamete fusion is:
A. Cross-pollination
B. Asexual reproduction
C. Fertilization
D. Sexual reproduction

Correct Answer: Option B


Explanation:
Asexual reproduction (binary fission, budding, fragmentation, vegetative propagation) produces genetically identical offspring from a single parent. Sexual reproduction involves gamete fusion. Fertilization is gamete union.

This question belongs to: Science Biology
Question #2
The mineral that is essential for the action of insulin and is a component of many enzymes is:
A. Calcium
B. Zinc
C. Sodium
D. Magnesium

Correct Answer: Option B


Explanation:
Zinc is required for the synthesis, storage (as hexamers), and secretion of insulin in pancreatic beta cells. It also acts as a cofactor for numerous enzymes like carbonic anhydrase and DNA polymerases. Calcium is for bones/signaling, magnesium for ATP and chlorophyll, sodium for nerve impulses.

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Question #3
The pulmonary veins carry:
A. Oxygenated blood from heart to body
B. Oxygenated blood from lungs to heart
C. Deoxygenated blood from body to heart
D. Deoxygenated blood from heart to lungs

Correct Answer: Option B


Explanation:
The pulmonary veins are the only veins in the body that carry oxygenated blood. They transport oxygen-rich blood from the lungs back to the left atrium of the heart. In contrast, the pulmonary artery carries deoxygenated blood from the right ventricle to the lungs. All other veins carry deoxygenated blood and arteries carry oxygenated blood.

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