Biology MCQs

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The genes for cytoplasmic male sterility in plants are located in the Mitochondrial genome.

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Phosphorus is required for nitrogen fixation by Rhizobium. This is a genus of Gram-negative soil bacteria.

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A plasmid is used as a tool to insert genes into bacteria to stimulate the production of therapeutic proteins such as human insulin.

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Bt toxin is produced by a bacterium called Bacillus thuringiensis.

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RNA interference is the method of cellular defense in animals and plants.

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Insulin is central to regulating carbohydrate and fat metabolism in the body. It stops the use of fat as an energy source by inhibiting the release of glucagon. It removes excess glucose from the blood, which otherwise would be toxic. Insulin helps blood sugar enter the body’s cells so it can be used for energy. Insulin also signals the liver to store blood sugar for later use. Blood sugar enters cells, and levels in the bloodstream decrease, signaling insulin to decrease too.

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The Bacillus Calmette–Guérin (BCG) vaccine is used to prevent tuberculosis (TB). The BCG vaccine is named after Dr Albert Calmette and Dr Camille Guerin, who developed the vaccine from a germ called Mycobacterium bovis, which is similar to TB. BCG is a live vaccine that has been processed so that it is not harmful to humans. Tuberculosis is an infectious disease caused by bacteria that affects the lungs, and sometimes other parts of the body.

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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).

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Oxygen is one of several dissolved gases important to aquatic systems. Dissolved oxygen is necessary to maintain aerobic conditions in surface waters and is considered a primary indicator when assessing the suitability of surface waters to support aquatic life. Dissolved oxygen can be measured in two ways: either in milligrams per litre (mg/L) or percent saturation (% sat). Water with an oxygen concentration of less than 3 mg/L will generally not support fish. When concentrations fall to about 3-4 mg/L, fish start gasping for air at the surface or huddle around the water fall (higher concentration points). Above 5 mg/L, almost all aquatic organisms can survive indefinitely, provided other environmental parameters are present within allowable limits.

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Blood group AB individuals have both A and B antigens on the surface of their RBCs, and their blood plasma does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but cannot donate blood to either A or B group. They are known as universal recipients.