Biology MCQs

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Rhizobium Found in roots of legumes, like Peas, grams, Pulses etc, where it fixes atmospheric nitrogen as ammonia, which is then converted into useful amino acid.

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The spleen, which is located under the ribcage and above the stomach in the left upper quadrant of the abdomen is the largest organ in the lymphatic system. It is that organ where RBC are selectively destroyed/ recycled by macrophages.

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The formation of Urea takes place in Liver. Urea which is also known as carbamide, is a waste product of many living organisms. It is the major organic component of human urine.

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Glycogen is stored mainly in liver and muscles. It is a multibranched polysaccharide of glucose. It serves as a form of energy storage in animals, fungi, and bacteria.

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Kala Azar is also known as Dum dum fever and Visceral leishmaniasis . Its caused by protozoa of Leishmania genus, vector is sandfly

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Viruses are small infectious agents that can replicate only inside the living cells of an organism. Viruses are classified based on the type of genetic material they contain. Some viruses have DNA as their genetic material, while others have RNA. Some viruses have both DNA and RNA as their genetic material.

DNA viruses have double-stranded DNA as their genetic material. They replicate their DNA using the enzymes and machinery of the host cell. Examples of DNA viruses include herpes viruses, pox viruses, and adenoviruses.

RNA viruses have single-stranded RNA as their genetic material. They replicate their RNA using the enzymes and machinery of the host cell. Examples of RNA viruses include influenza viruses, HIV, and coronaviruses.

Viruses that have both DNA and RNA as their genetic material are known as “retroviruses.” These viruses contain a single strand of RNA, but they use an enzyme called reverse transcriptase to convert their RNA into DNA. The DNA is then integrated into the host cell’s genome and replicated along with the host cell’s DNA. Examples of retroviruses include HIV and the human T-cell leukemia virus.

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Jonas Edward Salk was an American virologist and medical researcher who developed one of the first successful polio vaccines. He announced on a national radio show that he has successfully tested a vaccine against polio.

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Bombay Blood Group is an extremely rare ABO group, called so because it was first discovered among some people in Bombay. Their red cells lack ABH antigens and their sera contain anti-A and anti-B and anti-H. The anti-H would not be detected in the ABO group but would be detectable in pretransfusion tests. People who have Bombay phenotype can donate to any member of the ABO blood group system (unless some other blood factor gene, such as Rhesus, is incompatible), but they cannot receive any member of the ABO blood group system`s blood (which always contains one or more of A and B and H antigens), but only from other people who have Bombay phenotype

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Ishihara Test is used for the diagnosis of ‘Colour-Blindness’ in people. The test contains a number of colored plates, called Ishihara plates. Each of these plates contain a circle of dots appearing randomized in color and size.

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Azolla, also known as mosquito fern, is used as a biofertilizer because it has a symbiotic relationship with nitrogen-fixing cyanobacteria. The cyanobacteria, Anabaena azollae, lives on the leaves of Azolla and can fix atmospheric nitrogen. This nitrogen-fixing ability increases the fertility of the soil and enhances crop yields.
Azolla is a small aquatic fern that grows on the surface of water or moist soil. It is used as a biofertilizer for rice in Asia. Azolla can be grown as a green manure before transplanting rice or as an intercrop with the rice. Both practices are reported to increase the growth and yield of rice.
Azolla is also used as animal feed, human food, medicine, and water purifier.