In plant physiology, the 'Imbibition' is a special type of diffusion where water is absorbed by solid particles (colloids), causing them to increase in volume. This process is crucial for: MCQ with Answer and Explanation

In plant physiology, the 'Imbibition' is a special type of diffusion where water is absorbed by solid particles (colloids), causing them to increase in volume. This process is crucial for:
A. The initial absorption of water by dry seeds, leading to germination
B. The translocation of sugars in the phloem
C. The opening and closing of stomata
D. The ascent of sap in tall trees
Answer: Option A
Solution (By JKSSB Mock Tests)
Imbibition is a physical process where solid, hydrophilic (water-loving) colloidal materials (like cellulose, pectin, proteins, and starch) adsorb water, causing a tremendous increase in their volume and generating significant imbibitional pressure. This process is the very first step in seed germination. When a dry seed is exposed to water, its cell walls and storage materials imbibe water, causing the seed to swell, rupturing the seed coat, and initiating the metabolic activities required for the seedling to grow. It is also responsible for the splitting of rocks by plant roots.

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Practice More Biology Questions

Question #1
Which of the following is an abiotic component of an ecosystem?
A. Consumers
B. Decomposers
C. Producers
D. Soil

Correct Answer: Option D


Explanation:
Abiotic components are non-living physical and chemical factors of an ecosystem, including soil, water, temperature, light, and minerals. Biotic components include producers (plants), consumers (animals), and decomposers (bacteria, fungi). The interaction between abiotic and biotic components drives ecosystem functions. Soil provides nutrients and a medium for plant growth.

This question belongs to: Science Biology
Question #2
The hormone that lowers blood calcium by depositing it in bones is:
A. Thyroxine
B. Parathyroid hormone
C. Calcitonin
D. Insulin

Correct Answer: Option C


Explanation:
Calcitonin, secreted by the thyroid gland, reduces blood calcium by inhibiting osteoclast activity and promoting calcium deposition in bones. Parathyroid hormone raises calcium. Thyroxine regulates metabolism, insulin lowers blood glucose.

This question belongs to: Science Biology
Question #3
The 'Hormone Calcitonin' is secreted by the parafollicular cells (C cells) of the thyroid gland and primarily acts to:
A. Increase blood glucose levels
B. Decrease blood glucose levels
C. Decrease blood calcium levels
D. Increase blood calcium levels

Correct Answer: Option C


Explanation:
Calcitonin is a peptide hormone secreted by the parafollicular cells (also known as C cells) of the thyroid gland. Its primary function is to lower (decrease) the level of calcium in the blood (hypocalcemic effect) when it becomes too high. It achieves this by inhibiting osteoclast activity in bones (reducing bone resorption) and stimulating calcium excretion by the kidneys. It has the opposite effect of parathyroid hormone (PTH), which increases blood calcium.

This question belongs to: Science Biology