General Science Questions (MCQs) for Competitive Examinations

Notes:
Jhum is a traditional form of shifting cultivation that is common in the North-East of India. Also known as slash and burn agriculture, it is practiced by the tribal groups in Arunachal Pradesh, Meghalaya, Mizoram and Nagaland and the hilly areas of Assam. Jhum involves clearing a piece of land by setting fire or clear felling and using the area for growing crops.

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Composting is the depomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for enriching soil. It is the chief way to recycle wastes.

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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:
Panthera pardus is the scientific name of leopard, one of the five “big cats” in the genus Panthera. It is a member of the family Felidae with a wide range in sub-Saharan Africa and parts of Asia. It belongs to the Chordata phylum, Mammalia class and Carnivora order.

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Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis. The vaccine was originally developed from Mycobacterium bovis which is commonly found in cows. It is on the World Health Organization’s List of Essential Medicines, the most effective and safe medicines needed in a health system.

Notes:
The gap between the two neurons is called the synapse. It is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron. Synapses are essential to neuronal function : neurons are cells that are specialized to pass signals to individual target cells, and synapses are the means by which they do so.

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The open circulatory system is a system in which fluid in a cavity called the hemocoel bathes the organs directly with oxygen and nutrients and there is no distinction between blood and interstitial fluid; this combined fluid is called hemolymph. Arthropods and mollusks have an open circulatory system.

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An isogenic graft or Isograft is a graft between genetically identical individuals (i.e. monozygotic twins). This type of graft donot pose any form of tissue rejection threat by recipient’s body.

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Meibomian glands are the tiny oil glands which line the margin of the eyelids (the edges which touch when the eyelids are closed). These glands secrete oil which coats the surface of our eyes and keeps the water component of our tears away from evaporating (drying out). Together, the water and the oil layer make up the tear film.

Notes:
Protein digestion begins in the stomach with the action of pepsin. Pepsin is the active protein-digesting enzyme of the stomach. When pepsin acts on the protein molecule, it breaks the bonds that hold the protein molecule together, called peptide bonds. Once broken, peptide bonds yield chains of amino acids linked together called polypeptides that are further digested in the small intestine with the help of trypsin, chymotrypsin, and carboxypeptidase.