General Science Questions (MCQs) for Competitive Examinations

Notes:
Nitrogen-fixing bacteria are microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen. Rhizobium is one such bacteria that is associated with leguminous plants (e.g., various members of the pea family). It invades the root hairs of host plants and convert free nitrogen to ammonia, which the host plant utilizes for its development.

Notes:
Enzymes are defined as biological catalysts. Chemically all enzymes are globular proteins. Each enzyme catalyses only one chemical reaction. Protein part of enzyme is known as Apoenzyme. It forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate.

Notes:
Both polio and chicken pox are caused by virus. Poliomyelitis, often called polio or infantile paralysis, is an infectious disease caused by the poliovirus; while, Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV).

Notes:
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:
Utricularia (also called bladderworts) is a genus of insectivorous plants. They occur in fresh water and wet soil as terrestrial or aquatic species. All Utri cularia are carnivorous and capture small organisms by means of bladder-like traps. Aquatic species feed on protozoa and rotifers swimming in water-saturated soil’ while terrestrial species feed on water fleas (Daphnia), nematodes and even fish fry, mosquito larvae and young tadpoles.

Notes:
Cuscuta (Dodder) is a genus of about 100-170 species of yellow, orange or red (rarely green) parasitic plants. Dodders are supremely adapted for a life of plunder and pillage. Reduced in form to scrambling and twining threads, they appear to be completely leafless, although closer inspection reveals tiny scale leaves pressed close to the stems. So, it is a stem parasite.

Notes:
A fossil is the naturally preserved remains or traces of organisms that lived in the geologic past. There are two main types of fossils; body and trace. Body fossils include the remains of organisms that were once living, and trace fossils are the signs that organisms were present (i.e. footprints, tracks, trails, and burrows).

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Riboflavin, also known as vitamin B2 is an easily absorbed colored micronutrient with a key role in energy metabolism, and for the metabolism of fats, ketone bodies, carbohydrates, and proteins.

Notes:
The eustachian tube is a canal that connects the middle ear to the nasopharynx. It controls the pressure within the middle ear, making it equal with the air pressure outside the body. The cochlear nerve is also known as the acoustic nerve. It transfers auditory information from the cochlea (auditory area of the inner ear) to the brain. The malleus transmits the sound vibrations from the eardrum to the incus, and then to the stapes.

Notes:
Composting is defined as the biological degradation process of heterogeneous solid organic materials under controlled moist, self-heating, and aerobic conditions to obtain a stable material that can be used as organic fertilizer. It is formally known as “natural organic reduction”.