General Science Questions (MCQs) for Competitive Examinations

Notes:
Red Blood Corpuscles (RBCs) do not contain mitochondria when matured. These are the site of aerobic respiration. They they also lack the oxidative enzymes that are required for aerobic respiration. For this reason, Embden-Meyerhof pathway is used to process glucose and thus obtain energy. This is an anaerobic energy producing process that has been shown to use glycogen in the absence of glucose.

Notes:
The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

Notes:
The liver produces urea and other waste materials and then it pours it all in the right ventricle of the heart for oxygenation. The heart then distributes the blood to various parts of the body. So the impure blood brought by the Hepatic Vein and other blood vessels gets distributed through the aorta. This clearly indicates that hepatic vein from kidneys carries the largest amount of urea, while the renal vein from kidneys carries the least.

Notes:
Methane (CH4) is a greenhouse gas and causes warming the same way that CO2 does. It absorbs radiation emitted from the surface and re-emits that radiation in all directions with some of the radiation returning to the surface where it is absorbed and converted to heat. In the first two decades after its release, methane is 84 times more potent than carbon dioxide.

Notes:
An insect is an organism having three pairs of jointed legs. Insects are small, land-dwelling arthropods. It has three distinct body sections : the head, thorax and abdomen. It has one pair of antennae (comprising the scapele, pedicel and flagellum), compound eyes and often one or two pairs of wings.

Notes:
Carbohydrates are the main and quick energy source for human beings. Simple carbohydrates (like sugar-sweetened beverages) are digested quickly and send immediate bursts of glucose (energy) into the blood stream. Complex carbohydrates are digested more slowly and supply a lower steadier release of glucose into the blood stream.

Notes:
Cell theory was first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann. They stated that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells.

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:
The ovule matures to form the seed while the ovary, that is the outermost, forms the fruit. The seed coat is formed by the two integuments, which surround the embryo sac.

Notes:
Those who eat a well-balanced diet and have no metabolic disorders, excess dietary carbohydrates?are converted by the liver into complex chains of glucose called glycogen. Glycogen is stored in liver and muscle cells and is a secondary source of energy to freely circulating blood glucose.