General Science Questions (MCQs) for Competitive Examinations

Notes:
Fertilization in plants is not directly influenced by sunlight. Fertilization occurs after pollination, when pollen grains land on the stigma of a flower of the same species. During this time, a series of events take place leading to the formation of seeds. However, none of these event is affected by presence or absence of light.

Notes:
Bird and snake excretory product is uric acid. Nitrogenous waste is excreted in form of ammonia. In birds and reptiles, uric acid is the major end-product of protein metabolism. It is produced by the liver and excreted by kidney tubules; impaired elimination is an indication of renal disease.

Notes:
Plaster of Paris is a plaster made by calcining gypsum.
CaSO4•1/2?H2?O.
It can be used to impregnate gauze bandages to make a sculpting material called modroc. It is used to make classic plaster orthopedic casts to protect limbs with broken bones.

Notes:
Detoxification is the physiological or medicinal removal of toxic substances from a living organism which is mainly carried out by the liver. It breaks down or transforms substances like ammonia, metabolic waste, drugs, alcohol and chemicals, so that they can be excreted. The liver filter is designed to remove toxic matter such as dead cells, microorganisms, chemicals, drugs and particulate debris from the bloodstream.

Notes:
DNA does not directly control the formation of a polypeptide. However, it forms an intermediate template mRNA molecule, which directs the synthesis of polypeptide. The DNA can be compared to a master copy that is carefully preserved in the nucleus and used for preparing working copies in the form of mRNA molecules.

Notes:
Vitamin K refers to a group of fat-soluble vitamins that play a role in blood clotting, bone metabolism, and regulating blood calcium levels. The body needs vitamin K to produce prothrombin, a protein and clotting factor that is important in blood clotting and bone metabolism.

Notes:
Most of Earth’s oxygen comes from tiny ocean plants – called phytoplankton – that live near the water’s surface and drift with the currents. Like all plants, they photosynthesize – that is, they use sunlight and carbon dioxide to make food. Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth’s atmosphere (National Geographic).

Notes:
As per the report of WWF the ten most endangered rivers emerge as: the Salween, La Plata, Danube, Rio Grande, Ganges, Murray-Darling, Indus, Nile, Yangtze and Mekong.

Notes:
Breathing is the process in which air moves in and out of the lungs with the help of various respiratory organs. The process of taking in air rich in oxygen is called inhalation. Similarly, the process of giving out air rich in carbon dioxide is called exhalation. When we inhale, the ribs move up and outwards while the diaphragm moves down. An exact opposite movement occurs during exhalation when the ribs move down and inwards while the diaphragm moves up.

Notes:
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects. It is usually produced in the skin of human and animals under the influence of solar or ultraviolet radiation. In plants it can be produced from provitamin ergosterol.