General Science Mixed Quiz: Set 140

In plant cells RNA is found in the nucleus, the cytoplasm, mitochondria, chloroplasts and ribosomes. RNA is made in the nucleus, where DNA is copied into messenger, transfer and ribosomal RNA; the nucleolus in particular is rich in ribosomal RNA.

Ornithology is the study of birds, their classification, habits, migration and nesting; Salim Ali, known as the birdman of India, was the country's best known ornithologist and wrote the Book of Indian Birds.

Xerophytes are plants adapted to live in deserts and other places with very little water; the Greek word "xeros" means dry.

The liver weighs about one and a half kilograms and is both the largest gland and the largest internal organ of the body; it secretes bile, stores glycogen, iron and vitamin A, converts ammonia into urea and detoxifies drugs and poisons.

Palaeontology is the study of fossils, the preserved remains or traces of organisms of past geological ages, and it supplies the evidence on which the history of life and the theory of evolution rest.

High pressure pushes the gas molecules close together and low temperature slows them down, so the attractive forces can hold them as a liquid.

DNA copies itself from loosened chromatin, and chromatin condenses into chromosomes before division, but prokaryotes divide differently from eukaryotes. In a non-dividing eukaryotic cell, DNA lies in the nucleus as a loose network called chromatin.

Crown gall is caused by the bacterium Agrobacterium tumefaciens, which enters through a wound near the base, or crown, of the stem and makes the plant grow rough tumour-like swellings there.

The total mass of the reactants equals the total mass of the products, which is exactly what this law states.

The de Broglie wavelength depends only on momentum, so equal wavelengths mean equal momenta. In 1924 Louis de Broglie proposed that every moving particle has a wave linked to it, with wavelength λ = h/p, where h is Planck's constant and p is the linear momentum.

Xylem carries water together with the minerals dissolved in it from the roots to the stem and leaves, so blocking it stops both.

The spring constant is force divided by extension, so its SI unit is newton per metre. Hooke's law says that, within the elastic limit, the restoring force of a spring is proportional to how far it is stretched or compressed: F = −kx.

Argemone mexicana, the prickly poppy known in India as satyanashi, has seeds that look very like mustard seeds, so its oil is a classic adulterant of mustard oil.

These three oxides, made by heating limestone with clay, form the compounds that make cement set and harden. Portland cement was patented by Joseph Aspdin in England in 1824, and named after Portland stone, which the set cement resembled.

Sericulture is the rearing of silkworms for the production of raw silk, and it includes the growing of mulberry, on whose leaves the mulberry silkworm feeds; India produces mulberry silk as well as the wild varieties tasar, eri and muga, the last being special to Assam.

With no external force on the system, its centre of mass cannot start moving. The throw is an internal force: X pushes the tool forward and the tool pushes X backward with an equal and opposite force (Newton's third law).

Four grams of hydrogen gas is two moles, so it contains 2 × 6.022 × 10²³, about 1.2 × 10²⁴ molecules, not 6.022 × 10²³.

Osmosis is the movement of water from a dilute solution to a more concentrated one across a selectively permeable membrane.

Khesari dal, botanically Lathyrus sativus and also called grass pea, is a hardy pulse that survives drought and is therefore sometimes mixed with arhar dal or besan.

Entomology is the branch of zoology that deals with insects, the largest class of animals, and it covers their structure, classification, life cycles and their role as pests and pollinators.