Which of the following is an example of a biofertilizer containing a free-living nitrogen-fixing bacterium?
A. Nostoc
B. Mycorrhiza
C. Rhizobium
D. Azotobacter
Answer: Option D
Solution (By JKExamLibrary)
Azotobacter is a free-living, aerobic, nitrogen-fixing soil bacterium used as a biofertilizer for non-legume crops like wheat, maize, and cotton. Rhizobium is symbiotic, Nostoc is a cyanobacterium (algal biofertilizer), and mycorrhiza is a fungal symbiont that enhances phosphorus uptake. Biofertilizers reduce the need for chemical nitrogen fertilizers and are eco-friendly.
Explanation:
Oxidative phosphorylation occurs on the inner mitochondrial membrane, where the electron transport chain creates a proton gradient, and ATP synthase uses this gradient to produce ATP. This is the major source of cellular energy. Nucleus stores DNA, Golgi processes proteins, ribosomes synthesize proteins.
Explanation:
Blood group O has neither A nor B antigens on the red blood cells, but has both anti-A and anti-B antibodies in plasma. It is the universal donor for red cells. Group AB has both antigens, A has A antigen, B has B antigen.
Explanation:
Convergent evolution occurs when distantly related organisms independently evolve similar traits or structures to adapt to similar ecological niches or environmental pressures. The resulting structures are called analogous organs (e.g., wings of birds and insects, eyes of octopuses and mammals). Divergent evolution is when related species evolve different traits (homologous organs). Coevolution is when two species evolve in response to each other.
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