The phenomenon of bending of plant shoot towards a unilateral light source is due to:
A. Uniform distribution of auxin
B. Photolysis of chlorophyll
C. Inhibition of growth by light
D. Differential distribution of auxin, with higher concentration on shaded side
Answer: Option D
Solution (By JKSSB Mock Tests)
Phototropism (positive in shoots) is caused by the migration of auxin to the shaded side of the shoot, promoting cell elongation more on that side, causing the shoot to bend towards light. This asymmetric auxin distribution was demonstrated by Went's experiments. Auxin is sensitive to light and moves laterally. This is a growth response to directional light.
Explanation:
DNA is typically a double-stranded helical molecule carrying genetic information. Genes are specific sequences of DNA located linearly on chromosomes. RNA is generally single-stranded and contains the nitrogenous base uracil instead of thymine, which is found in DNA. Therefore, statements 1 and 3 are correct, while statement 2 is incorrect.
Explanation:
Calcium ions (Ca2+) play a crucial role in the blood clotting (coagulation) cascade. They are required for the conversion of prothrombin to thrombin, and fibrinogen to fibrin. Without calcium, the clotting process cannot proceed, which is why calcium salts are often added to blood collection tubes to prevent clotting during tests.
No comments yet. Be the first to start the discussion!