Biology MCQs

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The ovary is surrounded by a thin covering of epithelium, surrounds the ovarian stroma, and is divided into two regions – the outer cortex and the inner medulla.

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Ovaries are the primary sex organs of the female reproductive system. They produce the female gamete (ovum) and several steroid hormones.

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Chickenpox is a highly contagious disease caused by the varicella zoster virus.

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Malaria is an acute febrile illness caused by Plasmodium parasites. Malaria is a parasitic disease that is transmitted to humans through the bite of infected mosquitoes.

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Down’s syndrome is an example of a chromosomal disorder. Whereas Albinism, Haemophilia, and Sickle cell anemia are examples of Mendelian Disorder.

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Leber’s Hereditary Optic Atrophy is a type of Mitochondrial Inheritance that occurs due to mutations in a single gene and can be easily detected by pedigree analysis.

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Kala-azar is a parasitic disease that is confined to humans which is caused by the Leishmania donovani parasite. It is harboured by an insect called the sand-fly. The term “kala-azar” comes from India where it is the Hindi for black fever. The name “Leischmania donovani” honors two men: the British pathologist William Boog Leishman who in 1903 wrote about the protozoa that causes kalaazar and the researcher C. Donovan, who made the same discovery independently the same year.

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Rings of cartilage are present in the throat, specifically in the trachea or windpipe, to ensure that the air passage does not collapse. These semi-circular rings provide the necessary structural support to keep the airway open regardless of pressure changes that occur during breathing. This is very important for maintaining a clear, open path for air to flow into our lungs for respiration.

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Most cases of filariasis are caused by the parasite known as Wuchereria bancrofti. A wide range of mosquitoes can transmit this parasite, depending on the geographic area. In Africa, the most common vector is Anopheles while in the Americas, it is Culex quinquefasciatus. Aedes and Mansonia transmits transmit the infection in the Pacific and in Asia. Thus, Culex, Aedes and Anopheles mosquitoes serve as vector for W. bancrofti in transmission of the disease. Aedes mosquito causes dengue fever. Anopheles mosquito causes malaria. Culex mosquito causes filaria. A wide range of mosquitoes can transmit the parasite, depending on the geographic area. In Africa, the most common vector is Anopheles and in the Americas, it is Culex quinquefasciatus. [This question was wrongly framed in exam as “filaria is caused by__:”. GKtoday has edited it to make it correct.]

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.