General Science Questions (MCQs) for Competitive Examinations

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:
Linseed are the seeds of the flax plant, which are the source of linseed oil and linseed cake. Flax is a member of the genus Linum in the family Linaceae. Linseed is one of the most potent sources of omega- 3 fatty acids found in nature.

Notes:
Liver is considered as the biochemical laboratory of the human body. It synthesizes and secretes at least four important hormones and has a wide range of functions, including detoxification of various metabolites, protein synthesis, and the production of biochemicals necessary for digestion. It is tied to all bodily processes because it is responsible for filtration of all incoming foods and fluids. Some of the most important functions (among 500 functions carried out by it) are:
• Metabolizes proteins, fats, and carbohydrates, thus providing energy and nutrients
• Stores vitamins, minerals, and sugars
• Filters the blood and helps remove harmful chemicals and bacteria
• Creates bile which breaks down fats Helps to assimilate and store fat soluble vitamins (A, E, D, K); etc.

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.

Notes:
In general, liver is a good source of vitamin A, iron, zinc, copper and manganese, and a very good source of protein. There are twenty grams of protein in a single slice of liver.

Notes:
Cell wall is found in plants, bacteria, fungi, algae, and some archaea. Animal cells do not have cell walls, nor do protozoa. It is a structural layer situated outside the cell membrane that provides the cell with both structural support and protection, and also acts as a filtering mechanism.

Notes:
The majority of the upper respiratory epithelium is lined with cilia, small hair-like structures that move together like oars to push the mucus and its trapped contents to the throat, where it is swallowed. Each cell has about 300 cilia.

Notes:
Metamorphosis is a process by which animals undergo extreme, rapid physical changes some time after birth. Commonly known examples of metamorphosis include the process undergone by most insects, and the transformation of tadpoles into frogs. Hormones called molting and juvenile hormones, which are not species specific, apparently regulate the changes.

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:
Deciduous teeth are the first set of teeth in the growth development of humans and many other mammals. The deciduous teeth are: incisors
[D]; molars (6); and canine
[B]. So there are 12 teeth which get replaced by the age of 12 years when only permanent teeth remain.