The process of converting atmospheric nitrogen into ammonia by microorganisms is called: MCQ with Answer and Explanation

Explanation:
The plasma membrane (cell membrane) is primarily composed of a phospholipid bilayer with embedded proteins, following the fluid mosaic model, regulating transport in and out of the cell. The nucleus is the membrane-bound organelle that houses the cell's genetic material (DNA) organized into chromosomes. Mitochondria are the site of aerobic cellular respiration and ATP production; chloroplasts are the organelles where photosynthesis occurs in plant cells. Thus, statements 1 and 2 are correct.

Explanation:
Pantothenic acid (vitamin B₅) is a component of coenzyme A (CoA), essential for the Krebs cycle and fatty acid metabolism. Thiamine is TPP, riboflavin FAD, biotin for carboxylation.

Explanation:
Chlorophyll a is the primary photosynthetic pigment that acts as the reaction center in photosystem I (P700) and II (P680), converting light energy to chemical energy. Accessory pigments like chlorophyll b, carotenes, and xanthophylls absorb light and transfer energy to chlorophyll a. Phytochrome is involved in photoperiodism. Without chlorophyll a, photosynthesis cannot occur.