General Science Questions (MCQs) for Competitive Examinations

Notes:
A heart attack occurs when blood flow to a part of your heart is blocked for a long enough time that part of the heart muscle is damaged or dies. The medical term for this is myocardial infarction. Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart is starved of oxygen and heart cells die.

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:
Nitrogen-fixing bacteria are microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen. Rhizobium is one such bacteria that is associated with leguminous plants (e.g., various members of the pea family). It invades the root hairs of host plants and convert free nitrogen to ammonia, which the host plant utilizes for its development.

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The wings of insects, bats and birds, that evolved independently in each lineage separately after diverging from an ancestor without wings, are examples of analogous organs. Analogous organs are the opposite of homologous organs, which have similar functions but different origins.

Notes:
Trochodendron is a genus of flowering plants with one living species. It is vesselless angiosperm. Fewer than 200 species of angiosperms have the primitive feature of vesselless wood. With two exceptions— Trochodendron and Tetracentron; all vesselless angiosperms occur in the Magnolidae.

Notes:
Claspers are organs found in male elasmobranchs. Each male has two claspers. They are located along the inner side of the shark or ray’s pelvic fin and are used in reproduction. During mating, the male deposits his sperm into the female’s cloaca (the opening that serves as the entrance to the uterus, intestine and urinary tract) via grooves that lie in the upper side of the claspers.

Notes:
Sphygmomanometer an instrument for measuring blood pressure. It typically consists of an inflatable rubber cuff which is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic blood pressure by increasing and gradually releasing the pressure in the cuff. The sphygmomanometer was invented by Samuel Siegfried Karl Ritter von Basch in 1881.

Notes:
Bharat Biotech, a vaccine company, in December 2017, received Pre-Qualification tag from the World Health Organisation (WHO) for Typbar TCV or Typhoid Conjugate Vaccine. The WHO tag would allow the firm to access global public vaccination programmes. Typbar TCV is the first typhoid vaccine, clinically proven to be administered to children from six months of age to adults and confers long term protection against typhoid fever.

Notes:
Various components of blood are: Plasma, Erythrocytes (Red Blood Cells), Leucocytes (White Blood Cells) and Thrombocytes/Platelets. Monocytes, also known as macrophages, are the largest blood cells in most mammals, measuring 10-15 cm in diameter. They are leucocytes. Their nuclei are kidney-shaped and cytoplasm is abundant.

Notes:
Hh or the Bombay blood group, is a rare blood type. This blood phenotype was first discovered in Bombay, now known as Mumbai, by Dr. Y. M. Bhende in 1952. It is mostly found in South Asia (India, Bangladesh, Pakistan) and parts of Middle East such as Iran. Individuals with the rare Bombay phenotype (hh) do not express H antigen (also called substance H), the antigen which is present in blood group O. For this reason people who have Bombay phenotype can donate red blood cells to any member of the ABO blood group system but they cannot receive blood from any member of the ABO blood group system but only from other people who have Bombay phenotype.