General Science Questions (MCQs) for Competitive Examinations

Notes:
Chloroxylenol, also known as para-chloro-meta-xylenol, is an antiseptic and disinfectant which is used for skin disinfection and cleaning surgical instruments. It is also used within a number of household disinfectants and wound cleaners.

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.”

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Typhoid is a common worldwide bacterial disease transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella enterica subsp. enterica, serovar Typhi.

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Multicellular organisms are made up of more than one cell. The development of multicellular organisms is accompanied by cellular specialization and division of labor; cells become efficient in one process and are dependent upon other cells for the necessities of life. Paramecium is single-celled protists naturally found in aquatic habitats. Paramecium is the only genus in the family Parameciidae, which resides within the phylum Ciliophora.

Notes:
Carbon monoxide poisoning can be cured by exposing the affected person to fresh oxygen. It is because CO posoning leads to oxygen starvation of body cells. This therapy involves breathing pure oxygen in a chamber in which the air pressure is about two to three times higher than normal. This speeds the replacement of carbon monoxide with oxygen in your blood. Hyperbaric oxygen therapy may be used in cases of severe carbon monoxide poisoning.

Notes:
Taenia is a genus of tapeworm that includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans. There are more than 100 species recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids with proximal mouth called scolex.

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.

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Cyanobacteria, also known as blue green algae, are single-celled and belong to the family of Prokaryotes. That means, they do not have a well defined cell nucleus. The ability of cyanobacteria to perform oxygenic photosynthesis is thought to have converted the early reducing atmosphere into an oxidizing one, which dramatically changed the composition of life forms on Earth by stimulating biodiversity and leading to the near-extinction of oxygen-intolerant organisms.

Notes:
Infection is the invasion of an organism’s body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious diseases can be spread from one person to another, for example through contact with bodily fluids, by aerosols (through coughing and sneezing), or via a vector, for example a mosquito.

Notes:
The edible portion in an onion is swollen leaves with a bit of stem. They are bulbs which, like garlic and leeks, are modified stems in which the primary storage tissue is expanded leaf bases. They come in white, yellow, and red varieties. The swollen leaves have sugar as stored food in them.