General Science Questions (MCQs) for Competitive Examinations

Notes:
Thrombin is a serine protease, an enzyme, that is at the centre of blood clotting process in human beings. It catalyzes the conversion of fibrinogen to fibrin and activates procoagulant factors V, VIII, XI, and XIII. Additionally, when bound to thrombo-modulin, it activates protein C, an anticoagulant zymogen.

Notes:
Frogs that spend the coldest times of the year inside of the mud or within rotten heaps of leaves during hibernation receive their necessary oxygen through their skin. This is referred to as cutaneous gas exchange. They use their skin to soak in the oxygen their bodies require. Outside of hibernation period, frogs usually respire using their lungs.

Notes:
A vein is an elastic blood vessel that transports blood from various regions of the body to the heart. Veins are components of the cardiovascular system, which circulates blood to provide nutrients to the cells of the body. Veins can be categorized into four main types: pulmonary, systemic, superficial, and deep veins.

Notes:
Fermentation is the process by which complex organic compounds, such as glucose, are broken down by the action of enzymes into simpler compounds in the absence of oxygen (anaerobic). Yeasts can convert sugars to alcohol and carbon dioxide by fermentation. Fermentation is used to produce wine, beer, yogurt and other products.

Notes:
The constituents of phloem are Sieve tubes, Companion cells, Phloem parenchyma, Phloem fibres. Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. These are elongated narrow tube like cells with hard thick and lignified walls with large cell cavity.

Notes:
Cellular respiration is a catabolic process because it is breaking down glucose to eventually transfer energy into its usable form in ATP. An anabolic process builds things up, photosynthesis is a version of this and the metabolic opposite of cellular respiration.

Notes:
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.

Notes:
Cellular respiration takes place in the mitochondria. Cellular respiration allows for the release of energy stored in chemical bonds of glucose (obtained from food) to form adenosine triphosphate, which is the energy currency of the cell. For every molecule of glucose, 36 molecules of ATP are made.

Notes:
Oils are unsaturated carbon compounds that have double or triple bonds. Double and triple bonds are easy to be digested or to be broken down into simpler substances. But if a saturated compounds like Vanaspati Ghee are used, it becomes difficult for our body to digest the food as single bonds are not easily broken down into simpler substances by the acids present in our body. Animal fat is a saturated fat in which the fatty acid chains have all or predominantly single bonds. It is made of long chains of carbon (C) atoms. Saturated fatty acids are straight-chain organic acids with an even number of carbon atoms. They raise the serum LDL cholesterol concentration when they are consumed in the diet. So, they are harmful for our health.

Notes:
In human anatomy, the pleural cavity is the potential space between the two pleura (visceral and parietal) of the lungs. The pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. In pleural cavity of thorax lies three lobes of lungs on right side and two on the left hand side.