General Science Questions (MCQs) for Competitive Examinations

Notes:
Mercury belongs to the zinc group of elements in the periodic table, which comprises zinc, cadmium and mercury. They all have completely filled-up atomic orbitals. It becomes difficult to knock out these electron(s) from their orbitals and form metallic bonds. With its filled shell electron configuration it is very reluctant to form bonds even with other mercury atoms.

Notes:
The Moon has been bombarded with large quantities of Helium-3 by the solar wind. It is thought that this isotope could provide safer nuclear energy in a fusion reactor, since it is not radioactive and would not produce dangerous waste products.

Notes:
Connective tissue is a group of tissues in the body that maintain the form of the body and its organs and provide cohesion and internal support. Bone, ligaments, tendons, cartilage, and adipose (fat) tissue are examples of connective tissue. Cardiac muscle is an example of muscle tissue. It is so named because it is found in the heart.

Notes:
Calyptrogen is a layer of rapidly dividing cells at the tip of a plant root, from which the root cap is formed. It occurs in grasses and many other plants. The root cap is formed by several layers of cells that envelop the root tip externally. This covering of cells, of which the outermost ones are dead, envelops and protects the growing tip of root.

Notes:
An osteocyte, a star shaped cell, is the most commonly found cell in mature bone, and can live as long as the organism itself. Osteocytes are networked to each other via long cytoplasmic extensions that occupy tiny canals called canaliculi, which are used for exchange of nutrients and waste through gap junctions. The space that an osteocyte occupies is called a lacuna.

Notes:
Cuscuta (Dodder) is a genus of about 100-170 species of yellow, orange or red (rarely green) parasitic plants. Dodders are supremely adapted for a life of plunder and pillage. Reduced in form to scrambling and twining threads, they appear to be completely leafless, although closer inspection reveals tiny scale leaves pressed close to the stems. So, it is a stem parasite.

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:
Cotton is the most popular of the BT crops. In BT cotton, BT gene was isolated and transferred from a bacterium Bacillus thurigiensis to American cotton. The American cotton was subsequently crossed with Indian cotton to introduce the gene into native varieties. The BT cotton variety contains a foreign gene obtained from Bacillus thuringiensis. This bacterial gene, introduced genetically into the cotton seeds, protects the plants from bollworm (A. lepidoptora), a major pest of cotton.

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:
Nucleic acids are large biological molecules essential for all known forms of life. They include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). They are merely transmitted from one generation to next.