General Science Questions (MCQs) for Competitive Examinations

Notes:
Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism, catabolism meaning the breaking down of larger molecules into smaller ones. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The entire process from conversion of glucose to pyruvate is anaerobic that is it does not take place in presence of oxygen.

Notes:
Lysosomes are called the suicide bags of the cells they contain digestive enzymes, and break down food, cellular debris and foreign invaders like bacteria. When the cell is injured beyond repair, or becomes old, the lysosome digests the cell. So, it is called “suicide bag of the cell.”

Notes:
The major role of epidermis is to protect all the parts of the plant. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface. This aids in protection against loss of water, mechanical injury and invasion by parasitic fungi.

Notes:
Pulses are part of the legume family, but the term “pulse” refers only to the dried seed. Dried peas, edible beans, lentils and chickpeas are the most common varieties of pulses. The term “legume” refers to the plants whose fruit is enclosed in a pod. Other well-known legumes include alfalfa, clover, fresh peas, lupins, mesquite, soy and peanuts.

Notes:
Greenhouse gases that occur both naturally and from human activities include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone (O3). These gases contribute to atmospheric warming when they absorb infrared radiation emitted by the solar-warmed Earth and transfer their extra energy to the surrounding atmospheric gases.

Notes:
Composting is the depomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for enriching soil. It is the chief way to recycle wastes.

Notes:
These types of mechanism have been termed seismonastic movements. The movement occurs when specific regions of cells lose turgor pressure, which is the force that is applied onto the cell wall by water within the cell vacuoles and other cell contents.

Notes:
The leaves arise in the regions of the plant known as the plant nodes and are therefore the point of attachment of the leaves. The region of the plant between two nodes is known as the internode. The angle between the upper surface of the leaf and the stem from which it arises is known as the axil.

Notes:
The Theory of Evolution was developed by Charles Darwin (1809-1882). It states that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual’s ability to compete, survive, and reproduce. The theory gained general scientific acceptance after Darwin published On the Origin of Species in 1859.

Notes:
Sulphur dioxide (SO2) is considered as the most serious single air pollutant causing health hazard, obstructing breathing. It always leads to airways inflammation, eye irritation, psychic alterations, pulmonary oedema, heart failure and circulatory collapse. It is also responsible for acid rain.