The plant hormone that promotes cell division and is also used in tissue culture is:
A. Gibberellin
B. Auxin
C. Cytokinin
D. Abscisic acid
Answer: Option C
Solution (By JKExamLibrary)
Cytokinins are plant hormones that promote cytokinesis (cell division) and shoot initiation. They are used in tissue culture along with auxins to induce organogenesis. Auxins promote cell elongation and root initiation, gibberellins stem elongation, abscisic acid stress responses and dormancy.
Explanation:
Acetobacter aceti and related species oxidize ethanol to acetic acid (vinegar) in the presence of oxygen. This is an aerobic fermentation process. Lactobacillus produces lactic acid, Pseudomonas can spoil food, Bacillus includes various industrial strains. Vinegar is used as a condiment and preservative.
Explanation:
Iron (Fe²⁺) is at the center of the heme group in hemoglobin, enabling reversible oxygen binding. Calcium is in bones, magnesium in chlorophyll, zinc in many enzymes. Iron deficiency leads to anemia.
Consider statements about environment: 1. Biochemical Oxygen Demand (BOD) measures organic pollution. 2. Eutrophication is caused by excess nutrients. 3. Biological magnification decreases at higher trophic levels. Which are correct?
Explanation:
Biochemical Oxygen Demand (BOD) measures the amount of dissolved oxygen required by aerobic bacteria to decompose organic matter in water; high BOD indicates severe organic pollution. Eutrophication is the excessive enrichment of water bodies with nutrients (like nitrates and phosphates), leading to algal blooms and oxygen depletion. Biological magnification is the progressive increase in the concentration of non-biodegradable toxins (like DDT) at each successive trophic level, not a decrease. Thus, statements 1 and 2 are correct.
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