The scientist who proposed the 'one gene-one enzyme' hypothesis using Neurospora crassa was: MCQ with Answer and Explanation

The scientist who proposed the 'one gene-one enzyme' hypothesis using Neurospora crassa was:
A. Mendel
B. Beadle and Tatum
C. Watson and Crick
D. Morgan
Answer: Option B
Solution (By JKSSB Mock Tests)
George Beadle and Edward Tatum irradiated Neurospora crassa and showed that mutations in specific genes caused defects in specific enzymes, leading to the one gene-one enzyme concept. Watson and Crick discovered DNA structure, Mendel laws of inheritance, Morgan chromosome theory.

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Practice More Biology Questions

Question #1
Consider statements about ecology: 1. Producers form the base of the food chain. 2. Decomposers recycle nutrients back into the ecosystem. 3. Energy flows bidirectionally in a food chain. Which are correct?
A. 1 and 3 only
B. 1, 2 and 3
C. 1 and 2 only
D. 2 and 3 only

Correct Answer: Option C


Explanation:
Producers (autotrophs like green plants) form the first trophic level and the base of all food chains, converting solar energy into chemical energy. Decomposers (bacteria and fungi) break down dead organic matter and waste, releasing essential inorganic nutrients back into the soil for producers to use, thus completing the nutrient cycle. Energy flow in an ecosystem is strictly unidirectional, moving from the sun to producers and then to consumers, and is eventually lost as heat; it does not flow bidirectionally. Thus, statements 1 and 2 are correct.

This question belongs to: Science Biology
Question #2
The jelly-like substance that fills the cell and holds organelles is the:
A. Cytoplasm
B. Nucleoplasm
C. Matrix
D. Protoplasm

Correct Answer: Option A


Explanation:
Cytoplasm is the semifluid material between the plasma membrane and the nucleus, composed of cytosol, organelles, and inclusions. It is the site of many metabolic reactions. Nucleoplasm is inside the nucleus, protoplasm includes cytoplasm and nucleoplasm, and matrix refers to the inner compartment of mitochondria.

This question belongs to: Science Biology
Question #3
The tissue responsible for the transport of water in plants is:
A. Collenchyma
B. Xylem
C. Phloem
D. Epidermis

Correct Answer: Option B


Explanation:
Xylem is a complex permanent tissue that conducts water and dissolved minerals from roots to the aerial parts. It consists of tracheids, vessels, xylem parenchyma, and fibers. Phloem transports organic solutes, collenchyma provides flexible support, epidermis protects.

This question belongs to: Science Biology