Which of the following statements about lipids is correct?
A. Cholesterol is a protein.
B. Phospholipids are the main energy storage molecules.
C. They are soluble in water.
D. Triglycerides are composed of glycerol and three fatty acids.
Answer: Option D
Solution (By JKSSB Mock Tests)
Triglycerides are glycerol + 3 fatty acids; they are hydrophobic. Phospholipids are membrane components; triglycerides are main energy storage. Cholesterol is a steroid lipid, not protein.
Consider statements about angiosperms: 1. They have enclosed seeds. 2. They exhibit double fertilization. 3. All angiosperms are trees. Which are correct?
Explanation:
Angiosperms are flowering plants where seeds are enclosed within a mature ovary (fruit). They are characterized by double fertilization, where one male gamete fuses with the egg and the other with the secondary nucleus. They exhibit immense diversity in habit, ranging from tiny aquatic Wolffia to massive trees, so not all are trees. Statements 1 and 2 are correct.
Explanation:
A mature embryo sac (female gametophyte) in angiosperms is 7-celled but 8-nucleate: 3 antipodal cells (3 nuclei), 2 synergids (2 nuclei), 1 egg cell (1 nucleus), and 1 central cell with 2 polar nuclei. Thus total 8 haploid nuclei. The central cell is homodiploid (2 polar nuclei). Double fertilization involves these nuclei. This is typical of Polygonum type of development.
Consider the following statements about vitamins:
1. Vitamin C deficiency causes scurvy.
2. Vitamin D deficiency causes beriberi.
3. Vitamin A deficiency causes night blindness.
Which of the above is/are correct?
Explanation:
Scurvy is vitamin C deficiency; night blindness is vitamin A deficiency. Beriberi is due to vitamin B₁ deficiency, not D. So 1 and 3 are correct.
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