General Science Questions (MCQs) for Competitive Examinations

Notes:
Battery acid is sulphuric acid that has been diluted with water to attain a 37% concentration level. This particular type of acid is used in sealed lead acid batteries, however, concentration levels differentiate with some brands. These batteries use a combination of lead plates and an electrolyte consisting of a diluted sulphuric acid to convert electrical energy into potential chemical energy and back again.

Notes:
Transport of soluble products of photosynthesis is called translocation. Translocation of soluble products of photosynthesis occurs in the part of the vascular tissue known as the phloem. The phloem is the principle food conducting tissue associated with xylem in the vascular system.

Notes:
Swim bladder is also known as air bladder for fishes. It is a buoyancy organ possessed by most bony fishes. The swim bladder is located in the body cavity and is derived from an out-pocketing of the digestive tube. It contains gas (usually oxygen) and functions as a hydrostatic, or ballast, organ, enabling the fish to maintain its depth without floating upward or sinking. It also serves as a resonating chamber to produce or receive sound.

Notes:
The smallest bone in the human body is the stapes. The stapes is one of three small bones in the middle ear that allow mammals to transmit sound waves through their eardrum and hear. The stape bone is also known as the stirrup bone because it is shaped like a stirrup.

Notes:
The nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

Notes:
The reason why bacteria does not grow in high concentration of sugar is because of sugar’s high osmotic and dehydrating effects. Sugar, in aqueous form, attempts to reach equilibrium with the sugar content of the food product with which it is in contact. This has the effect of drawing available water from within the food to the outside and inserting sugar molecules into the food interior. The result is a reduction of the so-called product water activity, a measure of unbound, free water molecules in the food that is necessary for microbial survival and growth. Sugar’s other antimicrobial mechanisms include interference with a microbe’s enzyme activity.

Notes:
‘Survival of the fittest’ is a phrase that originated from Darwinian evolutionary theory as a way of describing the mechanism 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 Dar-win’s biological ones.

Notes:
The spleen is not an endocrine gland. This is because the spleen is not capable of aiding in the regulation of the hormone levels in the human body.

Notes:
The activity of enzymes, which are generally globular proteins, is determined by their three-dimensional structure. This structure allows them to bind to a substrate and catalyze their involvement in a reaction. Enzymes vary in size, ranging from 62 amino acid residues for the monomer of 4-oxalocrotonate tautomerase, to over 2,500 residues in animal fatty acid synthase. Their specific ability to bind to substrates enables reactions to occur in the body, playing a crucial role in metabolism.

Notes:
Fermentation is the process by which complex organic compounds, such as glucose, are broken down by the action of enzymes into simpler compounds in the absence of oxygen (anaerobic). Yeasts can convert sugars to alcohol and carbon dioxide by fermentation. Fermentation is used to produce wine, beer, yogurt and other products.