General Science Questions (MCQs) for Competitive Examinations

Notes:
Vitamin K is a group of structurally similar, fat-soluble vitamins the human body requires for complete synthesis of certain proteins that are prerequisites for blood coagulation. It is noteworthy for the synthesis of Prothrombin (coagulation factor II) that forms thrombin in the clotting process. Without vitamin K, blood uncontrolled bleeding occurs.

Notes:
Virology is the branch of science that deals with the study of viruses. It focuses on the following aspects of viruses: their structure, classification and evolution, their ways to infect and exploit host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, and their use in research and therapy.

Notes:
“Survival of the fittest” is a phrase originated in evolutionary theory, as an alternative description of natural selection. Herbert Spencer first used the phrase – after reading Charles Darwin’s On the Origin of Species – in his Principles of Biology (1864), in which he drew parallels between his own economic theories and Darwin’s biological one. Darwin first used Spencer’s new phrase “survival of the fittest” as a synonym for natural selection in the fifth edition of “On the Origin of Species by natural selection” published in 1869.

Notes:
HIV’s enzyme for inserting the DNA version of its genome into the host cell DNA is called its “integrase”. HIV-1 integrase catalyzes the “cut-and-paste” action of clipping the host DNA and joining the proviral genome to the clipped ends. It is also produced by viruses containing double-stranded DNAs for the same purpose.

Notes:
Parenchyma cells containing ergastic substances are called idioblasts. Tannin cells, cells filled with raphides, etc. constitute idioblast. An idioblast is an isolated plant cell that differs from neighboring tissues. It carries out storage of reserves in form of fats or oils wastes.

Notes:
The epidermis of the stem and the leaf is usually surrounded by a thin, covering called cuticle. It is formed by a waxy substance called cutin. It is meant for preventing excessive evaporation of water. Cuticle is absent in the root epidermis.

Notes:
Three common sugars (glucose, galactose and fructose) share the same molecular formula: C6H12O6. Because of their six carbon atoms, each is a hexose. They are “single” sugars or monosaccharides.

Notes:
Ringworm, also known as dermatophytosis or tinea, is a fungal infection of the skin or scalp. The name “ringworm” is a misnomer, since the infection is caused by a fungus, not a worm. The infection initially presents with red patches on affected areas of the skin and later spreads to other parts of the body.

Notes:
Glucose (C6H12O6), also called dextrose, is one of a group of carbohydrates known as simple sugars (monosaccharides). It is found in fruits and honey and is the major free sugar circulating in the blood of higher animals. It is the most important source of energy for cellular respiration. Glucose is stored as a polymer, in plants as starch and in animals as glycogen.

Notes:
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.