General Science Questions (MCQs) for Competitive Examinations

Notes:
Tachycardia is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 80 beats per minute is accepted as tachycardia in adults. A healthy adult heart normally beats 60 to 100 times a minute when a person is at rest. Tachycardia occurs when an abnormality in the heart produces rapid electrical signals.

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:
The types of vertebrate animals which creep and crawl are called reptilians. These include lizards and snakes.

Notes:
Normal blood pressure is considered to be at or below 120 over 80 (120/80). Normally, blood pressures are usually categorized into three groups: low (90/60 or lower), high (140/90 or higher), and normal (values above 90/60 and below 130/80).

Notes:
Cloves are the aromatic dried flower buds of a tree in the family Myrtaceae. The clove tree is an evergreen that grows to a height ranging from 8–12 m, having large leaves and sanguine flowers in numerous groups of terminal clusters. The flower buds are at first of a pale colour and gradually become green, after which they develop into a bright red, when they are harvested by farmer.

Notes:
Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of carbohydrates (sugar). The main product of photosynthesis is glucose, which is the molecule that produces energy to run the processes of the cell. Oxygen is mainly a byproduct of the process of photosynthesis.
6H2O (water) + 6CO2 (carbon dioxide) = C6H12O6 (glucose) + 6O2 (oxygen)

Notes:
The carrot gets its characteristic and bright orange colour from ?-carotene, which is partly metabolised into vitamin A in liver of humans. Carotene is responsible for the orange colour of carrots and many other fruits and vegetables. Carotene is an orange photosynthetic pigment important for photosynthesis.

Notes:
Tropism is a growth movement whose direction is determined by the direction from which the stimulus strikes the plant. Most stems are positively phototropic, while most roots are said to be negatively phototropic and positively geotropic.

Notes:
Cholesterol is defined as a waxy alcohol, fat-like substance that occurs naturally in all areas of the human body. 100-200 mg/dL is considered as normal for the human beings. The total cholesterol counts below 180 mg/dl increase the risk for haemorrhagic stroke; and above 200 mg/dl may be normal and healthy for some people, as the ratio of LDL to HDL cholesterol is considered a more important factor in prediction of disease risk particularly heart disease.

Notes:
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. The chromosome holds not only the genetic code, but many of the proteins responsible for helping express it.