The pigment that gives plants their characteristic green color and is the main pigment for photosynthesis is:
A. Chlorophyll b
B. Carotene
C. Chlorophyll a
D. Xanthophyll
Answer: Option C
Solution (By JKSSB Mock Tests)
Chlorophyll a is the primary photosynthetic pigment, essential for converting light energy into chemical energy. It directly participates in the light reactions. Chlorophyll b, carotenes, and xanthophylls are accessory pigments that capture additional wavelengths and transfer energy to chlorophyll a. These accessory pigments also protect chlorophyll from photo-oxidation.
Explanation:
Vitamin D (cholecalciferol) is synthesized in the skin from 7-dehydrocholesterol under UV-B radiation. It then undergoes activation in the liver and kidneys. It regulates calcium and phosphate metabolism.
Consider statements about human diseases: 1. Influenza is caused by a virus. 2. Leprosy is caused by a fungus. 3. Malaria is transmitted by Anopheles mosquito. Which are correct?
Explanation:
Influenza (flu) is a respiratory illness caused by the influenza virus. Malaria is a parasitic disease caused by Plasmodium and transmitted exclusively by the bite of an infected female Anopheles mosquito. Leprosy (Hansen's disease) is a chronic infectious disease caused by the bacterium Mycobacterium leprae, not a fungus. Thus, statements 1 and 3 are correct.
Explanation:
A mid-cycle surge in LH (luteinizing hormone) from the anterior pituitary triggers ovulation—the release of the secondary oocyte from the mature Graafian follicle. FSH stimulates follicle development. Estrogen levels rise before ovulation and provide positive feedback for the LH surge. Progesterone is secreted after ovulation by the corpus luteum.
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