Teaching GK Questions 2026

A lysosome is a membrane-bound sac of powerful digestive enzymes that breaks down worn-out organelles and any foreign particle the cell takes in; if the cell is damaged or starving, the sacs burst and the same enzymes digest the cell itself, which is why the name suicide bag is used.

Both carry a small circular DNA of their own and their own 70S ribosomes, so they make a part of their protein themselves and divide independently of the cell; this semi-autonomous nature is the main evidence for the view that they descend from free-living bacteria engulfed by an early cell.

In 1665 he cut a thin slice of cork, examined it under a microscope of his own making and saw rows of empty boxes, which he named cells after the small rooms of a monastery; the drawing and description appeared in his book Micrographia.

The natural mineral form of mercuric sulphide is cinnabar, the chief ore of mercury, and its bright red powdered form has been used as the pigment vermilion for centuries.

Liquefied petroleum gas is a mixture of butane and propane and is by itself almost odourless, so a leak could fill a room unnoticed.

Temporary hardness is caused by the dissolved bicarbonates of calcium and magnesium. On boiling, these bicarbonates decompose into insoluble carbonates, which settle out as the scale seen in a kettle, so the water that remains is soft.

In a soda-acid extinguisher a solution of sodium hydrogen carbonate is kept in the body of the cylinder and sulphuric acid in a sealed glass phial.

When milk is set into curd, the bacteria Lactobacillus convert the milk sugar lactose into lactic acid, and it is this acid that gives curd its sour taste and makes the milk protein clot.

Aqua regia is a freshly prepared mixture of three parts concentrated hydrochloric acid to one part concentrated nitric acid. Neither acid alone attacks gold, but together they do, because the nitric acid oxidises the metal while the chloride ions hold the gold in solution as a complex.

Gypsum is calcium sulphate dihydrate, and heating it carefully to about 373 kelvin drives off three quarters of its water to leave calcium sulphate hemihydrate, which is Plaster of Paris.

It is a mild, non-corrosive base. In baking it releases carbon dioxide on heating and makes the dough rise, in medicine it neutralises excess acid in the stomach, and in a soda-acid fire extinguisher it reacts with sulphuric acid to produce the carbon dioxide that smothers the flame.

Boric acid dissolves in water to give a true solution, in which the dispersed particles are individual molecules small enough to pass through a filter paper and even a parchment membrane, and the mixture shows no Tyndall effect.

Rayon is made by dissolving the cellulose of wood pulp in a chemical and forcing the solution through fine holes to form filaments.

A dilute solution of iodine gives a deep blue-black colour with starch, which is a polysaccharide and therefore a carbohydrate.

In graphite each carbon atom is joined to only three other carbon atoms in flat hexagonal layers, so the fourth valence electron of every atom is not used in bonding and can move freely along the layer.

A block lying quietly on a table is in equilibrium, so the forces on it must add up to zero, but that does not mean there are no forces at all.

Mehrgarh, on the Bolan river in the Kachi plain of Baluchistan, is the earliest known farming village in the Indian subcontinent, occupied from about 7000 BCE.

A brand is the name, term, sign, symbol or design a seller gives a product so that buyers can tell it apart from everything else on the shelf.

When the British left in 1947, India had, besides the provinces under direct British rule, about 565 princely states whose rulers had accepted British paramountcy.

Plant tissues are first divided into meristematic tissue, whose cells keep dividing, and permanent tissue, whose cells have stopped dividing and have taken a fixed shape and job.