Pantothenic acid (vitamin B₅) is a component of coenzyme A (CoA), which is essential for the metabolism of carbohydrates, fats, and proteins via the Krebs cycle and fatty acid synthesis. Thiamine is TPP, biotin for carboxylation, folic acid for one-carbon transfer.
Consider the following statements about viruses:
1. The tobacco mosaic virus was the first virus discovered.
2. Viruses can have a protein coat called capsid.
3. Viruses can reproduce outside host cells.
Which of the above is/are correct?
Explanation:
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:
Active transport requires energy (ATP) to move molecules against their concentration gradient. The Sodium-Potassium pump (Na+/K+ ATPase) is a classic example, moving 3 Na+ ions out of the cell and 2 K+ ions into the cell per ATP hydrolyzed. Osmosis, diffusion, and facilitated diffusion are passive processes.
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