Biology MCQs

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Variation is the driving force of evolution. Genetic variation is the presence of differences in the sequences of genes between different organisms of a species.

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Bacteria, cyanobacteria and fungi are the main sources of biofertilizers. These trap atmospheric nitrogen and reduce it to ammonia and make it available to plants. They also convert insoluble phosphates into forms required by plants.

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Azospirillum is an example of a loose association of nitrogen-fixing bacteria. Azotobacter is an example of Free-Living Nitrogen-Fixing Bacteria. Rhizobium is an example of Symbiotic Nitrogen-Fixing Bacteria. Blue-Green alga is an example of Symbiotic Nitrogen-Fixing Cyanobacteria.

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A polymerase chain reaction is a chemical reaction used by molecular biologists to amplify fragments of DNA.

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Leptospirosis is a bacterial disease caused by corkscrew-shaped bacteria called Leptospira. Signs and symptoms can range from none to mild such as headaches, muscle pains, and fevers; to severe with bleeding from the lungs or meningitis. If the infection causes the person to turn yellow, have kidney failure and bleeding, it is then known as Weil’s disease.

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Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine. Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine. Amylase catalyses the breakdown of starch into maltose in the mouth and small intestine.

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Panthera pardus is the scientific name of leopard, one of the five “big cats” in the genus Panthera. It is a member of the family Felidae with a wide range in sub-Saharan Africa and parts of Asia. It belongs to the Chordata phylum, Mammalia class and Carnivora order.

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The small intestine, the part of the gastrointestinal tract between the stomach and the large intestine, is the main digester and absorber of food. The small intestine has three distinct regions – the duodenum, jejunum, and ileum–that carry out the absorption of nutrients and minerals from food. It converts the food into a semi-solid mass.

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The literal meaning of ‘sanguinivorous’ is someone subsisting on a diet of blood, or blood-sucking bats and animals. Mosquitoes belong to this category. Leech, female mosquitoes, vampire bats are other examples of Sanguivores.

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Mycoplasma is a genus of bacteria that lacks a cell wall around their cell membrane. Without a cell wall, they are unaffected by many common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. In comparison to other prokaryotes, they are consequently placed in a separate class Mollicutes(mollis, soft; cutis, skin).