Biology MCQs

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Infection is the invasion of an organism’s body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious diseases can be spread from one person to another, for example through contact with bodily fluids, by aerosols (through coughing and sneezing), or via a vector, for example a mosquito.

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Penicillin the so called ‘Wonder drug’ discovered by Alexander Fleming in 1927 is produced from the genus of fungi “Penicillia”. All penicillin are â-lactam antibiotics and are used in the treatment of bacterial infections caused by susceptible, usually Grampositive organisms.

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The clitellum is a thickened glandular and non-segmented section of the body wall near the head in earthworms and leeches, that secretes a viscid sac in which the eggs are deposited. Its main function is to store the eggs of the earthworm.

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Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The condition can be self-limiting (healing on its own) or can progress to fibrosis (scarring) and cirrhosis.

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Bulliform cells are large, bubble-shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. These cells, by their turgor changes, cause rolling and unrolling of the leaves thus regulating water loss.

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The islets of Langerhans are the regions of the pancreas that contain cells that produce hormones. There are five types of cells in the islets of Langerhans: beta cells secrete insulin; alpha cells secrete glucagon; PP cells secrete pancreatic polypeptide; delta cells secrete somatostatin; and epsilon cells secrete ghrelin.

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In human males, the sperms produced in testes are carried by a duct called vas deferens. The vas deferens unites with urethra coming from the urinary bladder. The urethra forms a common passage for both the sperm and urine as it is just one tube that connects both the glands– urinary bladder and vas deferens.

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The kidneys are the filtering devices of blood. The kidneys remove waste products from metabolism such as urea, uric acid, and creatinine by producing and secreting urine. Urine may also contain sulphate and phenol waste and excess sodium, potassium, and chloride ions.

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Fertilization is the process of fusion of the male and the female gametes. This can occur either inside (internal fertilization) or outside (external fertilization) the body of the female. Humans provide an example of the former whereas seahorse reproduction is an example of the latter.

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In molybdenum-deficient plants grown in the presence of nitrate, molybdenum is required for the synthesis of nitrate reductase. Molybdenum deficiency results in the decrease of free amino acids in the plants in comparison to normal plants.