General Science Questions (MCQs) for Competitive Examinations

Notes:
More than one option is correct. Jatropha curcas is known for its insecticidal, pesticidal and fungicidal properties. It is used in rural Bengal for dhobi itch (a common fungal infection of the skin). Pesticidal properties have also been reported from Pongamia Pinnata (Karanja) especially against nematodes.

Notes:
Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue. Each hemoglobin molecule is made up of four heme groups surrounding a globin group. Heme contains iron and gives a red color to the molecule.

Notes:
A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta. Fern ally is a general term covering a somewhat diverse group of vascular plants that are not flowering plants (angiosperms) and not true ferns. Like ferns, these plants reproduce by shedding spores to initiate an alternation of generations. Both Ferns and fern allies belong to Pteridophytes.

Notes:
Bone is a composite of proteins such as collagen and minerals such as calcium. Calcium phosphate is the major component of bones and teeth. Except for small portions of the inner ear, all hard tissues of the human body are formed of calcium phosphate. Collagen gives the bones a soft framework, while calcium makes them hard and strong.

Notes:
Pleiotropy describes the genetic effect of a single gene on multiple phenotypic traits. The underlying mechanism is that the gene codes for a product that is, for example, used by various cells, or has a signaling function on various targets. A classic example of pleiotropy is phenylketonuria, a human disease that affects multiple systems but is caused by one gene defect.

Notes:
Water is transported through the plant in Xylem vessels, these begin in the roots and end in the leaves of the plant. Water is transported through a combination of “Transpirational pull” and capillary action that produces root pressure.

Notes:
Alveoli are an important part of the respiratory system whose function it is to exchange oxygen and carbon dioxide molecules to and from the bloodstream. These tiny, balloon-shaped air sacs sit at the very end of the respiratory tree and are arranged in clusters throughout the lungs. Alveoli are tiny balloon shaped structures and are the smallest passageway in the respiratory system.

Notes:
Vitamin C also known as ascorbic acid is found in citrus fruit such as orange, lemon, lime, grapefruit, grapes etc. It protects the immune system, reduces the severity of allergic reactions and helps fight off infections.

Notes:
R.H. Whittaker (1969) proposed a Five Kingdom Classification: Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.

Notes:
Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants from a contaminated site. It uses naturally occurring organisms to break down hazardous substances into less toxic or non-toxic substances. There are two classes of bioremediation used : In situ and Ex situ.