The 'Hormone Calcitonin' is secreted by the parafollicular cells (C cells) of the thyroid gland and primarily acts to:
A. Decrease blood glucose levels
B. Increase blood calcium levels
C. Decrease blood calcium levels
D. Increase blood glucose levels
Answer: Option C
Solution (By JKSSB Mock Tests)
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.
Explanation:
The cuticle is a waxy, water-repellent layer secreted by epidermal cells on the outer surface of leaves and young stems. It minimizes water loss through transpiration. Its thickness varies with plant species and habitat; xerophytes often have a thick cuticle. The epidermis is the tissue layer, palisade and spongy mesophyll are photosynthetic tissues.
Explanation:
Stem bears leaves and reproductive structures. It is positively phototropic (grows towards light). Leaves are the main photosynthetic organs. Roots grow downward.
Explanation:
Human somatic cells are diploid (2n = 46), with 23 pairs of homologous chromosomes. Gametes (sperm and egg) are haploid (n = 23), containing one set of chromosomes. Fertilization restores diploidy. The haploid number is 23. Option 22 would be autosomes plus one sex chromosome, but the total count is 23. 44 is the number of autosomes in somatic cells.
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