General Science Questions (MCQs) for Competitive Examinations

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Conglobate gland is a leaf like, median, unbranched gland of male cockroach. It lies below the ejaculatory duct and open into the genital pouch close to the male genital aperture.

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Coupling and repulsion are indeed two states of linkage in genetics. Genetic linkage refers to the tendency for genes that are located close on a chromosome to be inherited together during meiosis. The compounding of genes establishes linkage. As genes become more proximal, they exhibit closer linkage. Gametes with linked genes from coupling and repulsion crosses are often combined.

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Hibernation is a state of greatly reduced metabolic activity and lowered body temperature adopted by certain mammals as an adaptation to adverse winter conditions. The term hibernation is commonly applied to all types of winter dormancy in vertebrate animals. Among mammals, true hibernators are found only in the orders Chiroptera (bats), Insectivora (hedgehogs and allies), and Rodentia (ground squirrels, marmots, etc).

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In order for the cell cytoplasm to communicate with the external environment, materials must be able to move through the plasma membrane. Osmosis is the movement of water from a region of higher concentration to one of lower concentration. Osmosis occurs across a membrane that is semipermeable.

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An allosome is a sex chromosome that differs from an ordinary autosome in form, size, or behaviour. The human sex chromosomes are a typical pair of allosomes. In typical ovum, there is a pair of X-chromosomes while sperm has X and Y chromosome each.

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Triploblasty is a condition of the blastula in which there are three primary germ layers: the ectoderm, mesoderm, and endoderm. The germ layers form during gastrulation of the blastula. All “higher” and “intermediate animals” (from flat worms to humans), arise from a triploblastic ovum. Triploblastic organisms generally possess bilateral symmetry.

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The richest sources of protein are animal foods such as chicken, meat, fish, cheese and eggs. However, plant proteins are believed to be healthier because of their lower fat content. Plant protein is found (e.g.) in beans (esp. soy beans), lentils, nuts, quorn and seeds. Fish and seafood are some of the richest sources of protein. Soybeans are legumes that provide a valuable protein-rich food option for vegetarians and non-vegetarians alike. One cup of boiled soybeans provides over 28g of protein.

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Time required for the organism to eliminate 50 per cent of the total body burden or tissue concentration of chemical is referred to as Half Life Period. A biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose one-half of its pharmacologic, physiologic, or radiological activity.

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Hydrogen peroxide (H2O2) is a water molecule with an extra oxygen atom hence, also called oxygenated water. It is very unstable and breaks down readily into water and a single oxygen molecule. So in nutshell, when Hydrogen peroxide readily loses active oxygen, Water is formed.
2H2O2 —> 2H2O + O2

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Vitamins A, D, E, and K are the fat-soluble vitamins. Unlike water-soluble vitamins, these vitamins dissolve in fat and are stored in body tissues. Too much vitamin A, D, or K (Hypervitaminosis) can lead to increased levels that are unhealthy and can cause health consequences. For example, too much vitamin A can lead to birth defects.