General Science Questions (MCQs) for Competitive Examinations

Notes:
Ornithology is a branch of zoology that deals with the study of birds. The science of ornithology has developed several key concepts in evolution, behaviour and ecology such as the definition of species, the process of speciation, instinct, learning, ecological niches, guilds, island biogeography, phylogeography and conservation.

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The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the “master gland” of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating other glands to produce other hormones.

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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:
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:
Lysosomes are membrane-enclosed organelles that are known as suicidal bags of the cell. They contain digestive enzymes, and break down food, cellular debris and foreign invaders like bacteria. In the event that the cell is injured beyond repair, or becomes old, the lysosome digests the cell, hence the name ‘suicide bag of the cell’.

Notes:
Frogs that spend the coldest times of the year inside of the mud or within rotten heaps of leaves during hibernation receive their necessary oxygen through their skin. This is referred to as cutaneous gas exchange. They use their skin to soak in the oxygen their bodies require. Outside of hibernation period, frogs usually respire using their lungs.

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Microorganisms or decomposers such as bacteria and fungi help in the process of recycling of nutrients by decomposing various dead organisms such as plants and animals to form humus. Humus is highly nutritious and rich in minerals and microbes vital for healthy plant growth.

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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.

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Fructose, or fruit sugar, is a simple ketonic monosaccharide found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is a 6-carbon polyhydroxyketone with chemical formula of C6H12O6.

Notes:
R.H. Whittaker (1969) proposed a Five Kingdom Classification: Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.