Biology MCQs

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T-cells are involved in cell-mediated immunity. T cells are produced in the bone marrow and mature in the thymus.

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Rinderpest is a highly contagious viral disease of cattle. Rinderpest is an ancient plague of cattle and other large ruminants. It belongs to the Paramyxoviridae family.

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A molecule whose interaction with water and other polar substances is more thermodynamically favorable than its interaction with oil or other hydrophobic solvents is called a hydrophilic molecule. Sugar, salt, starch, and cellulose are examples of hydrophilic molecules.

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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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Hydra is radially symmetrical, that is, the parts of its body are arranged in a circle around a central median axis passing through the mouth. Hydra reproduces by asexual and sexual methods. Asexual reproduction takes place either by budding or by fission.

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The chromosomes which determine the sex (maleness or femaleness) of an individual in sexually producing organisms are called sex chromosomes or allosomes. In humans an individual whose cells contain XX chromosomes (homo or isogametic) becomes a female, while one whose cells contains XY chromosomes (heterogametic) becomes a male.

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A normal adult mouth has 32 teeth, which (except for wisdom teeth) have erupted by about age 13. The canines are situated at the ‘corners’ of the dental arches. They have a sharp, pointed biting surface. Their function is to grip and tear food. There are four canine teeth in both primary and permanent dentitions.

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Enzymes are sometimes called biological catalysts because they speed up reactions, and only small amounts are required. Digestive enzymes speed up the breakdown of complex food substances into simpler subunits. The breakdown of food in digestion is actually caused by water chemically splitting the complex food molecules, a process called hydrolysis.

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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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Pulses come under the category of dicot seeds as they contain two cotyledons, hence the term ‘dicotyledon’ where ‘di’ symbolizes two. These seeds house two seedlings within their seed coat. Furthermore, the legume plant family, composed of various types of pulses, beans, peas, and lentils, are common instances of dicot seeds.