General Science GK Questions with Answers – Page 2

Tritium is the only radioactive isotope of hydrogen; its nucleus is unstable and decays by giving out beta particles. Hydrogen has three natural isotopes, all with one proton but different numbers of neutrons.

The peacock is a bird and the camel is a mammal, and these are the only two groups of animals that are warm-blooded.

Penicillin stops bacteria from building their peptidoglycan cell wall, so the weakened cells burst and die. Penicillin binds to and blocks the transpeptidase enzymes, also called penicillin-binding proteins, that cross-link the peptidoglycan chains of the wall.

The Hardy-Weinberg principle states the opposite: allele frequencies in a population stay stable, that is constant, from generation to generation.

With no net force acting on it, the object keeps moving at the same speed in the same straight line.

Nereis, the clamworm, is an annelid, and annelids are bilaterally symmetrical: only one plane divides the body into identical left and right halves.

Sclerenchyma cells lay down thick walls hardened with lignin, and once the wall is complete the protoplasm dies. Sclerenchyma is the plant tissue that gives strength and rigidity.

A prokaryotic cell has no true nucleus, so its genetic material is not wrapped in a nuclear membrane. Bacteria and cyanobacteria are prokaryotes.

Hallucinations, most often hearing voices that others cannot hear, are a core symptom of schizophrenia. Schizophrenia is a serious mental disorder in which a person loses touch with reality.

Agaricus is a mushroom, a fungus that feeds on dead and decaying organic matter, which is the saprophytic mode of nutrition.

Phloem carries the sugars made in the leaves to every part of the plant that needs food. Phloem is a complex permanent tissue made of four kinds of cells: sieve tubes, companion cells, phloem parenchyma and phloem fibres.

The Calvin cycle fixes carbon dioxide into sugar without needing light directly, so it forms the light-independent (dark) reactions. Photosynthesis happens in two stages inside the chloroplast.

Lateral meristems divide along the sides of the stem and root and add new cells that make them thicker. Meristems are groups of cells that keep dividing.

Female Anopheles mosquitoes bite humans because they need blood to mature their eggs, and the malaria parasite can cross the placenta.

The speed of light in a medium is inversely proportional to its refractive index, so the ratio of speeds is the inverse ratio of the refractive indices.

The so-called lead of a pencil is a mix of graphite and clay; it contains no lead metal. Graphite is a crystalline form, or allotrope, of carbon.

A liquid has no shape of its own, so it must be measured inside a vessel that expands at the same time.

G has the same value everywhere in the universe, for any two masses. The relation is Newton's law of universal gravitation: every two bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

The Kelvin and Fahrenheit scales read the same at about 574.25, which is about 301 degrees Celsius. The scales are linked by K = C + 273 and F = (9/5)C + 32.

The lens of the human eye is a converging (convex) lens, not a diverging one, so statement A is not correct.