The vitamin whose active form, retinol, is essential for vision is:
A. Vitamin D
B. Vitamin E
C. Vitamin C
D. Vitamin A
Answer: Option D
Solution (By JKSSB Mock Tests)
Vitamin A (retinol) is converted to retinal, which combines with opsin to form rhodopsin, the light-sensitive pigment in rod cells of the retina. Deficiency leads to night blindness and xerophthalmia. Carrots and liver are rich sources. Vitamin C is ascorbic acid, D is calciferol, E is tocopherol.
Explanation:
RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is the most abundant protein on Earth and the key enzyme in the Calvin cycle (C3 pathway). It catalyzes the fixation of CO2 by attaching it to Ribulose-1,5-bisphosphate (RuBP) to form a 6-carbon intermediate that immediately splits into two molecules of 3-PGA.
Explanation:
The medulla oblongata contains the respiratory rhythmicity centre that controls the rate and depth of breathing. The pons also has pneumotaxic and apneustic centres influencing breathing. The cerebrum can exert voluntary control, cerebellum coordinates movement, and hypothalamus regulates homeostasis.
Explanation:
Pinocytosis (cell drinking) is a type of endocytosis where the cell membrane forms small vesicles to engulf extracellular fluid and dissolved substances. Phagocytosis is for large particles, exocytosis is export, endocytosis is general term.
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