General Science Questions (MCQs) for Competitive Examinations

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Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability.

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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.

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Pneumonia is a bacterial disease caused by Streptococcus pneumoniae, a Gram-positive bacterium. It lives in the noses and throats of healthy people and can enter lungs through inhalation. Other important Gram-positive causes of pneumonia are Staphylococcus aureus and Bacillus anthracis.

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The spleen is not an endocrine gland. This is because the spleen is not capable of aiding in the regulation of the hormone levels in the human body.

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There are three types of heterotrophs: herbivores, carnivores and omnivores. Also referred to as consumers, heterotrophs are organisms that obtain their energy from organic compounds. In other words, they are organisms that are unable to produce their own food (unlike autotrophs) and therefore have to consume/ ingest organic compounds as a source of energy.

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Vitamin C also known as ascorbic acid is found in citrus fruit such as orange, lemon, lime, grapefruit, grapes etc. It protects the immune system, reduces the severity of allergic reactions and helps fight off infections.

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The sigmoid colon is the last section of the bowel — the part that attaches to the rectum. It’s about a foot and a half long (around 40 centimeters) and is shaped like the letter “s.” The sigmoid colon is a short curving of the colon, just before the rectum. It is part of the large intestine.

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Opium is the dried latex obtained from the opium poppy. Opium contains approximately 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. The latex also includes codeine and non-narcotic alkaloids such as papaverine, thebaine and noscapine.

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Test tube baby is born from in vitro fertilization. In vitro fertilization (IVF) is a process by which an egg is fertilized by sperm outside the body: in vitro. When a woman’s natural cycle is monitored to collect a naturally selected ovum (egg) for fertilization, it is known as natural cycle IVF. The fertilized egg (zygote) is then transferred to the patient’s uterus with the intention of establishing a successful pregnancy.

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Dolly was the world’s first cloned sheep. It was born on 5 July 1996. It was a female domestic sheep, and the first mammal cloned from an adult somatic cell, using the process of nuclear transfer. Dolly was cloned by Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute, part of the University of Edinburgh, Scotland.