General Science Questions (MCQs) for Competitive Examinations

Notes:
Phototropism is the growth of organisms in response to light. In plants, phototropism is a response to blue wavelengths of light and is caused by a redistribution of auxin from the illuminated side to the darker side of the shoot, resulting in quicker growth on the darker side and bending of the shoot toward the source of light.

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The National Institute of Mental Health and Nuro- Sciences is a premier medical institution located in Bengaluru, India. NIMHANS is the apex centre for mental health and neuroscience education in the country, the institute operates autonomously under the Ministry of Health and Family Welfare.

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All verteberates have notochord, body cavity and gills in their embryonic stage or adult stage but not have haemocoel. It’s presence is well marked in the members of phylum in Arthopoda.

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Chlorophyll, a photo-receptive pigment, allows plants to absorb sunlight. Chlorophyll is a chlorine pigment, which is structurally similar to and produced through the same metabolic pathway as other porphyrin pigments such as heme. At the center of the chlorine ring is a magnesium ion. The molecular formula of C55H70O6N4 Mg. Hence, chlorophyll as a pigment lacks calcium.

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The cerebellum is known as little brain. It is a region of the brain that plays an important role in motor control. i.e. in maintaining and coordinating body posture at different times of the day/night.

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Thrombin is a serine protease, an enzyme, that is at the centre of blood clotting process in human beings. It catalyzes the conversion of fibrinogen to fibrin and activates procoagulant factors V, VIII, XI, and XIII. Additionally, when bound to thrombo-modulin, it activates protein C, an anticoagulant zymogen.

Notes:
The deficiency of magnesium leads to yellowish green blotch near the base of the leaf between the midrib and the outer edge (chlorosis). The yellow area enlarges until the only green remaining is at the tip and base of the leaf as an inverted V-shaped area on the midrib.

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An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. When excessive amounts of acids are produced in the stomach the natural mucous barrier that protects the lining of the stomach can damage the esophagus in people with acid reflux. Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage and relieving pain.

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Wilhelm Johannsen was a Danish botanist, plant physiologist and geneticist. His most well-known research concerned so-called pure lines of the self-fertile common bean. He was able to show that even in populations homozygous for all traits, i.e. without genetic variation, seed size followed a normal distribution. This was attributable to resource provision to the mother plant and to the position of seeds in pods and of pods on the plant. This led him to coin the terms phenotype and genotype and introduce the term gene. This term was coined in opposition to the then common pangene that stemmed from Darwin’s theory of pangenesis.

Notes:
A goitre, or goiter, is a swelling in the neck resulting from an enlarged thyroid gland. A goitre can be associated with a thyroid that is not functioning properly. Worldwide, over 90% of goitre cases are caused by iodine deficiency. The term is from the Latin gutturia, meaning throat.