Chiasmata, the visible points of crossing over, become clearly visible during which sub-stage of Prophase I?
A. Zygotene
B. Pachytene
C. Diplotene
D. Leptotene
Answer: Option C
Solution (By JKSSB Mock Tests)
Chiasmata become clearly visible during the diplotene stage of Prophase I. While the actual exchange of genetic material (crossing over) occurs during the pachytene stage, the homologous chromosomes begin to repel each other and move apart in diplotene, remaining connected only at the sites of crossing over, which appear as X-shaped chiasmata. Exam tip: Pachytene = crossing over; Diplotene = chiasmata visible.
Explanation:
ATP synthase (CF₀-CF₁ complex) uses the proton gradient across the thylakoid membrane to synthesize ATP. Rubisco fixes CO₂, NADP reductase reduces NADP⁺, PEP carboxylase is in C4 plants.
Consider the following statements about carbohydrates:
1. Glucose is a monosaccharide.
2. Sucrose is a disaccharide.
3. Cellulose is a storage polysaccharide in plants.
Which of the above is/are correct?
Explanation:
Glucose is a monosaccharide, sucrose a disaccharide (glucose+fructose). Cellulose is a structural polysaccharide, not storage; starch is storage. So 3 is incorrect.
Explanation:
Neutrophils are the most abundant white blood cells, constituting about 60-65% of the total WBC count. They are polymorphonuclear and are highly phagocytic, acting as the first line of defense against bacterial infections. Lymphocytes are the second most abundant (20-25%), while monocytes and eosinophils are present in smaller percentages.
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