General Science Questions (MCQs) for Competitive Examinations

Notes:
The Indian gooseberry, or Amla from Sanskrit Amalika, is a deciduous tree of the family Phyllanthaceae. It is known for its edible fruit of the same name. Although these fruits are reputed to contain high amounts of ascorbic acid (Vitamin C), 445 mg/100g, the specific contents are disputed, and the overall antioxidant strength of Amla may derive instead from its high density of ellagitannins such as emblicanin A (37%), emblicanin B (33%), punigluconin (12%) and pedunculagin (14%). It also contains punicafolin and phyllanemblinin A, B, C, D, E and F. There is preliminary evidence in vitro that its extracts induce apoptosis and modify gene expression in osteoclasts involved in rheumatoid arthritis and osteoporosis. It may prove to have potential activity against some cancers.

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Rabi refers to agricultural crops sown in winter and harvested in the spring. Examples of Rabi Crops: Wheat, Gram, Pea, Mustard, Linseed, Barley. Rice is a Kharif crop, cultivated and harvested during the rainy (monsoon) season in the South Asia.

Notes:
Olfactory receptor, also called smell receptor, are present in the nose. It is a protein capable of binding odour molecules that plays a central role in the sense of smell (olfaction). It is responsible for the detection of odorants which give rise to the sense of smell. Activated olfactory receptors trigger nerve impulses which transmit information about odour to the brain.

Notes:
Pulses come under the category of dicot seeds as they contain two cotyledons, hence the term ‘dicotyledon’ where ‘di’ symbolizes two. These seeds house two seedlings within their seed coat. Furthermore, the legume plant family, composed of various types of pulses, beans, peas, and lentils, are common instances of dicot seeds.

Notes:
A type of helicase enzyme called DNA helicase catalyzes the unwinding of the DNA helix at the time of replication. It uses the energy released through hydrolysis of ATP (Adenosine triphosphate) to break the hydrogen bonds between the two strands. The enzyme is needed to separate the two strands of DNA also during transcription and DNA repair. Topoisomerase prevents rewinding of strands after halicase action.

Notes:
Vitamin K is a group of structurally similar, fat-soluble vitamins that are needed for the post translational modification of certain proteins required for blood coagulation i.e. conversion of fibrinogen into fibrin, the blood clot. and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4- naphthoquinone (3-)derivatives. This group of vitamins includes two natural vitamins: vitamin K1 and vitamin K2. Vitamin K1, also known as phylloquinone, phytomenadione, or phytonadione, is synthesized by plants, and is found in highest amounts in green leafy vegetables because it is directly involved in photosynthesis. It may be thought of as the “plant form” of vitamin K. It is active in animals since animals can easily convert it to vitamin K2.

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Compound eyes are found among the arthropods and are composed of many simple eye sets called ommatids. These may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cells. Some eyes have up to 28,000 such sensors, which are arranged hexagonally give a full 360° field of vision. Compound eyes are very sensitive to motion. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high resolution images.

Notes:
Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue. Each hemoglobin molecule is made up of four heme groups surrounding a globin group. Heme contains iron and gives a red color to the molecule.

Notes:
The nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

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The primary function of the red blood cells, or erythrocytes, is to carry oxygen from the lungs to body tissues and to transfer carbon dioxide from the tissues to the lungs. The RBC is a count of the number of red blood cells per cubic millimeter of blood. Newborns: 4.8 – 7.2 million Adults: (males): 4.6 – 6.0 million