General Science Questions (MCQs) for Competitive Examinations

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Saprophytes are the organisms which depend for food on dead and decaying material. They secrete digestive substances into the surrounding environment and break down the organic matter into simpler substances. The nutrients thus produced are absorbed directly through the cell membranes of the organisms.

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Based on the dividing capacity of the tissues, various plant tissues can be classified as growing or meristematic tissue and permanent tissue. Meristem is a type of tissue system in plants, composed of a mass of undifferentiated cells and their primary function is to take part in the growth of plants. Permanent tissues are differentiated tissues doing specific functions such as conduction, providing mechanical support or carrying out photosynthesis etc.

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Growth hormone or somatotropin, also known as human growth hormone in its human form, is a peptide hormone that stimulates growth, cell reproduction and cell regeneration in humans and other animals. It is thus important in human development.

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The small intestine, the part of the gastrointestinal tract between the stomach and the large intestine, is the main digester and absorber of food. The small intestine has three distinct regions – the duodenum, jejunum, and ileum–that carry out the absorption of nutrients and minerals from food. It converts the food into a semi-solid mass.

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Sharks possess a heterocercal caudal fin in which the dorsal portion is usually noticeably larger than the ventral portion. This is because the shark’s vertebral column extends into the dorsal portion, providing a greater surface area for muscle attachment.

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Typhoid fever, also known simply as typhoid, is a bacterial infection due to Salmonella typhi, also known as Salmonella enterica serotype typhi, that grows in the intestines and blood. Typhoid is spread by eating or drinking food or water contaminated with the feces of an infected person.

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In the blood the key minerals are iron, copper, zinc, sodium, potassium, calcium and magnesium. Minerals constitute important part of blood plasma that constitutes almost 55% of blood. In the blood, iron is found in larger amounts than any other mineral.

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The word “protoplasm” comes from the Greek protos for first, and plasma for thing formed, and was originally used in religious contexts. It was first used for living cells by J. E. Purkinje, a Czech anatomist and physiologist, in 1839. He used protoplasm for the fluid substance of a cell.

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Entomology, branch of anthropology and study of zoology, deals with the scientific study of insects. The Greek word entomon, meaning “notched,” refers to the segmented body plan of the insect. The zoological categories of genetics, taxonomy, morphology, physiology, behaviour, and ecology are included in this field of study.

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Guard cells interact physiologically and mechanically with subsidiary cells. Guard cells are those which have chloroplasts and control the opening of stomata. But, subsidiary cells are those which support the guard cells and they do not have chloroplasts.