Biology MCQs

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Plasma is 55% of the blood by volume and constitutes 5% of the body weight. Plasma is a pale yellow transparent clear fluid which consists of 90-92% water and 8-10% organic and inorganic substances. Organic substances are mainly plasma proteins viz. albumin, globulin, prothrombin and fibrinogen. Albumins are responsible for maintenance of osmotic pressure of Blood. Globulins are chief sites for formation of antibodies; while prothrombin and fibrinogen are essential for clotting of blood

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Bile is secreted by Hepatocytes. It is a complex aqueous secretion that originates from hepatocytes. It is modified distally by absorptive and secretory transport systems in the bile duct epithelium.

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The shape of Vibrio bacteria is comma shaped. These bacteria naturally live in certain coastal waters and are present in higher concentrations between the months of May and October when water temperatures are warmer.

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The building blocks of the human body are cells. Cells are the smallest unit of life and they perform all the functions necessary for the body to function. There are many different types of cells in the body, including muscle cells, nerve cells, and blood cells. These cells are organized into tissues, which are groups of similar cells that work together to perform a specific function. Tissues are then organized into organs, which are structures made up of multiple tissues that work together to perform a specific function, such as the heart or the liver. Organs are then organized into systems, which are groups of organs that work together to perform a specific function, such as the respiratory system or the circulatory system. Together, these building blocks allow the body to function as a whole.

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Bryophytes are an informal group consisting of three divisions of non-vascular land plants: the liverworts, hornworts and mosses. They play a vital role in regulating ecosystems because they provide an important buffer system for other plants.

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As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra.

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When we respire, most of the carbon dioxide as bicarbonate ions is transported in the blood. The carbon dioxide dissolved in the blood reacts with water and by the help of zinc containing enzyme called carbonic anhydrase, they form carbonic acid. It immediately dissociates to give H+ and bicarbonate ions once carbonic acid is formed. The haemoglobin present in the erythrocytes (RBCs) combines with the H+ ions immediately. The bicarbonate ion goes into the blood plasma which creates an ionic imbalance between the plasma and the erythrocytes. The chloride ions then diffuse from the blood plasma into the RBCs to maintain the ionic balance. The process of chloride ion diffusing into the erythrocytes to maintain the ionic balance is described as Hamburger’s Phenomenon.

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The thymus gland produces the hormone thymosin. Thymosin stimulates the development of T cells, which fight disease. The thymus gland is located in the chest, between the lungs and behind the breastbone. It is active until puberty, after which it shrinks and is replaced by fat.
The thymus gland also produces thymopoietin and thymulin. Thymopoietin is a polypeptide hormone made up of 49 amino acids.

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Any legume plants will help in nitrogen fixation. Beans contain symbiotic bacteria called Rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants and this helps to fertilize the soil.

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K.V. Frisch shared the 1973 Nobel Prize in physiology or medicine with K. Lorenz and N. Tinbergen for his pioneering work in ethology. He deciphered the ‘language’ of bees by studying their dance patterns in which one bee tells others in the hive the direction and distance of a food source.