General Science Questions (MCQs) for Competitive Examinations

Notes:
An allosome is a sex chromosome that differs from an ordinary autosome in form, size, or behaviour. The human sex chromosomes are a typical pair of allosomes. In typical ovum, there is a pair of X-chromosomes while sperm has X and Y chromosome each.

Notes:
Early blight and late blight are two serious diseases of potato and tomato. Early blight of potato is caused by the fungus, Alternaria solani. The pathogen produces distinctive “bulls-eye” patterned leaf spots and can cause tuber blight on potato. This disease, also known as target spot, rarely affects young, vigorously growing plants. It is found on older leaves first.

Notes:
Quenching is a process in which absorbed light energy is dissipated as heat and does not take part in photochemistry. The phenomenon involves quenching of chlorophyll a fluorescence, which is induced under steady-state illumination.

Notes:
Green is the least effective color of light in driving photosynthesis, the process of converting light energy into chemical energy. Photosynthesis occurs in plants and algae using chlorophyll, and because chlorophyll reflects rather than absorbs green light, green light cannot be used in the photosynthetic process.

Notes:
Sugar, or table sugar, is also known as sucrose. There are actually many different types of sugars – glucose, galactose, fructose and lactose are all sugars, along with sucrose. A more complex example is sucrose (table sugar), which is 42.11% carbon, 6.48% hydrogen, and 51.41% oxygen by mass. Sucrose is made up of one molecule of glucose and one molecule of fructose joined together.

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 daily salt intake of camels is eight times that of a typical cow or sheep. Yet, surprisingly, they do not develop high blood pressure. Similarly, their blood sugar levels are twice those of other cud chewing animals; still they do not develop diabetes.

Notes:
The yolk sac is a membranous sac attached to an embryo, providing early nourishment. It functions as the developmental circulatory system of the human embryo, before internal circulation begins. It carries out transfer of nutrients in weeks 2 and 3 when the uteroplacental circulation is established

Notes:
Casein-Lactose protein-sugar pair is present in milk. Normal bovine milk contains 30-35 grams of protein per litre of which about 80 percent is arranged in casein micelles. Casein is present in milk, but it’s not a milk sugar like lactose. Instead, casein is one of the proteins found in milk. Unlike lactose, which causes an intolerance, these proteins in milk are what’s responsible for a milk allergy, according to Food Allergy and Research Education.

Notes:
During glycolysis, glucose is broken down in ten steps to two molecules of pyruvate in cytoplasm (in the cellular matrix called cytosol). It then enters the mitochondria where it is oxidised through the tricarboxylic acid cycle to carbon dioxide and water.