General Science GK Questions with Answers – Page 47

In the cytoplasm, glucose is split by glycolysis into two molecules of pyruvate, releasing a small amount of energy as ATP.

Living things are built up level by level: molecules such as proteins form cells, cells form tissues, tissues form organs, organs form organ systems, and these together make an organism.

pH falls, not rises, as hydrogen ion concentration rises, so a more acidic solution has a lower pH. pH is defined as the negative logarithm of the hydrogen ion concentration: pH = −log[H⁺].

Treating rock phosphate, which is insoluble calcium phosphate, with sulphuric acid gives superphosphate of lime, a fertiliser whose phosphorus plants can absorb.

A nitrogen molecule, N₂, is diatomic, not triatomic; its two atoms are joined by a triple bond, and the molecules attract each other only weakly.

The Food Safety and Standards Authority of India is the statutory body that lays down standards for food and regulates its manufacture, storage, sale and import across India.

Uric acid is the end product of the breakdown of purines, which come from the nucleic acids DNA and RNA, so gout patients are told to cut down purine-rich food.

It is called dry ice because, at ordinary pressure, it changes directly from solid to gas (sublimation) instead of melting, so it never makes anything wet.

Tin is a chemical element (symbol Sn, atomic number 50), a pure substance made of only one kind of atom, so it is not a mixture.

Air is optically rarer than water, so light speeds up, not slows down, when it passes from water into air.

When the force acts opposite to the displacement, the angle between them is 180°, and work W = F d cos 180° = −F d. Work done by a force is the product of the force, the displacement and the cosine of the angle between them.

Lymph forms when plasma leaks out of blood capillaries into the spaces between cells, so it is essentially plasma with less protein and no red blood cells.

The retina is the light-sensitive layer at the back of the human eye; it is not a part of any microscope.

Solid carbon dioxide is called dry ice because it turns straight into gas without melting into a liquid, so it leaves nothing wet behind.

Defining acids and bases by the H⁺ and OH⁻ ions they release in water is exactly the theory Svante Arrhenius gave in 1884.

Tritium gives out beta particles, not alpha particles, and a water molecule is bent, not linear, so these two statements are wrong.

In 5 seconds the sound travels to the mountain and back, a total of 340 × 5 = 1,700 m, so the mountain is half of that, 850 m or 0.85 km, away.

Both are pure forms of carbon, but their atoms are arranged differently, which gives them opposite physical properties. Diamond and graphite are allotropes of carbon.

Weight is the gravitational force with which the Earth pulls an object towards its centre. Weight is given by W = mg, where m is the mass and g is the acceleration due to gravity, about 9.8 m/s² near the Earth's surface.

Thomson proposed in 1904 that an atom is a sphere of positive charge with electrons embedded in it, like plums in a pudding or seeds in a watermelon.