General Science Questions (MCQs) for Competitive Examinations

Notes:
Mercury belongs to the zinc group of elements in the periodic table, which comprises zinc, cadmium and mercury. They all have completely filled-up atomic orbitals. It becomes difficult to knock out these electron(s) from their orbitals and form metallic bonds. With its filled shell electron configuration it is very reluctant to form bonds even with other mercury atoms.

Notes:
Nickel, Platinum and Darmstadtium belongs to Group number 10 whereas element Roentgenium is placed in group number 11.

Notes:
Fermentation is an anaerobic chemical process that breaks down glucose molecules. In baking, yeast consumes sugar and converts it into carbon dioxide and alcohol, making the dough rise. This gas gets trapped in the strands of gluten, resulting in air pockets that cause the dough to rise and form the characteristic spongy texture of bread and cakes. Further, the creation of lactic and acetic acids during fermentation augments this dough handling process, improves flavor, enhances the texture, and extends the shelf-life of the baked products.

Notes:
Radon, a radioactive noble gas with atomic number 86, is used in radiotherapy. Created by disintegration of radium, its one of the heaviest gases and a health hazard. Radon gas, chemically inert yet radioactive, can accumulate in buildings and drinking water causing lung cancer. Furthermore, radon is noted for brilliant phosphorescence when cooled below its freezing point. Its most stable isotope, 222Rn, has a half-life of 3.8 days. Groundwater often has a higher 222Rn concentration than surface water due to less exposure to atmosphere.

Notes:
Connective tissue is a group of tissues in the body that maintain the form of the body and its organs and provide cohesion and internal support. Bone, ligaments, tendons, cartilage, and adipose (fat) tissue are examples of connective tissue. Cardiac muscle is an example of muscle tissue. It is so named because it is found in the heart.

Notes:
Ecological succession is unidirectional progressive process of development in an ecosystem or biome. Grass ecosystems are an early stage of succession in regions where the mature ecosystems are forests. However, grass ecosystems are climax ecosystems in grassland regions, where there is not enough rainfall to support a forest. Due to limiting factors such as water scarcity and forest fire, a grassland ecosystem changes to a desert ecosystem. The ecological succession of grassland is desert.

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Tuberculosis caused by Mycobacterium tuberculie which primarily affects lungs although can affect other body too while early 19th century was called ‘white plague’ because of the large number of the people dying of its infection.

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The plastid is a major double-membrane organelle found in the cells of plants. Plastids are the site of manufacture and storage of important chemical compounds used by the cell. Plastids often contain pigments used in photosynthesis, and the types of pigments present can change or determine the cell’s colour.

Notes:
Tamarind tree (Tamarindus indica), Ashoka tree (Saraca Indica), Indian Coral tree (Erythrina Indica) have ‘Indica’ common in their botanical names. In biology/taxonomy, if a species originates in India, its scientific name sometimes includes “Indica”.

Notes:
Bacteriophage refers to any of a group of viruses that infect bacteria. Bacteriophages were discovered independently by Frederick W. Twort in Great Britain (1915) and Felix d’Herelle in France (1917). D’Herelle coined the term Bacteriophage, meaning “bacteria eater”.