In plant physiology, the 'Senescence' refers to the process of: MCQ with Answer and Explanation

In plant physiology, the 'Senescence' refers to the process of:
A. Seed germination
B. Rapid cell division
C. Flower opening
D. Aging and programmed death of plant organs or the whole plant
Answer: Option D
Solution (By JKSSB Mock Tests)
Senescence in plants is the biological process of aging, culminating in the structured, programmed death of plant organs (like leaves, flowers, or fruits) or the entire plant. It involves the coordinated breakdown of macromolecules (proteins, nucleic acids, chlorophyll) and the mobilization of nutrients (like nitrogen and phosphorus) from the senescing organ to other growing parts of the plant (like developing seeds). It is a highly regulated process influenced by hormones like ethylene and abscisic acid, and delayed by cytokinins.

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Practice More Biology Questions

Question #1
In a food chain, the first trophic level is always occupied by:
A. Herbivores
B. Carnivores
C. Producers (Green plants)
D. Decomposers

Correct Answer: Option C


Explanation:
A food chain represents the flow of energy and nutrients. The first trophic level is always occupied by producers (autotrophs), primarily green plants and algae, which convert solar energy into chemical energy via photosynthesis. The second level is primary consumers (herbivores), the third is secondary consumers (carnivores), and so on.

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Question #2
The scientist who discovered the phenomenon of transformation in bacteria was:
A. Avery
B. Griffith
C. Hershey
D. Chase

Correct Answer: Option B


Explanation:
Frederick Griffith in 1928 demonstrated transformation by showing that heat-killed virulent pneumococci could transfer virulence to live non-virulent bacteria. Avery et al. later identified the transforming principle as DNA.

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Question #3
Consider statements about human anatomy: 1. The sternum is located in the chest. 2. The clavicle is the collar bone. 3. The scapula is the shoulder blade. Which are correct?
A. 1 and 3 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2 and 3

Correct Answer: Option D


Explanation:
The sternum, or breastbone, is a flat bone located in the center of the chest, to which the ribs attach. The clavicle, commonly known as the collarbone, connects the arm to the body, running horizontally above the first rib. The scapula, or shoulder blade, is a flat, triangular bone located on the upper back, forming the posterior part of the shoulder girdle. All statements are correct.

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