General Science GK Questions with Answers – Page 55

Urine is made in the kidneys, carried down by the ureters, stored in the bladder and passed out through the urethra.

Protochordates are marine chordates that have a notochord at some stage but never develop a backbone. The phylum Chordata is split into protochordates and vertebrates.

A mutation is a change in the sequence of the DNA or RNA that carries a virus's genes. A virus is made of genetic material, either DNA or RNA, inside a protein coat.

Microbodies are small vesicles bounded by a single membrane, filled with enzymes that carry out particular metabolic reactions. The main microbodies are peroxisomes and glyoxysomes.

The work done against gravity is mgh = 50 × 10 × 8 = 4,000 J, and doing it in 10 s needs 4,000 ÷ 10 = 400 W. Power is the rate of doing work, P = W/t, and its SI unit is the watt (1 W = 1…

TB spreads through the air when an infected person coughs, sneezes or speaks and others breathe in the tiny droplets carrying the bacteria.

All three statements describe hard water correctly. Statement 1 is correct: temporary hardness comes from dissolved bicarbonates, chiefly calcium bicarbonate (magnesium bicarbonate too).

Platinum only gets hot and may glow; it does not react, and on cooling the crucible is exactly as it was, so the change is physical.

For reflection at a plane mirror, the deviation is 180° − 2i, and with i = 40° this gives 180° − 80° = 100°.

Resistivity equals resistance multiplied by area and divided by length, which leaves the unit ohm × length.

Jointed legs are the mark of the phylum Arthropoda, to which insects belong; an earthworm has no legs at all.

Resistance varies inversely with the area of cross-section, and doubling the diameter makes the area four times larger. The resistance of a wire is R = ρl/A, where ρ is the resistivity of the metal, l the length and A the cross-sectional area.

With the velocity changing steadily from 5 m/s to 7 m/s, the average velocity is 6 m/s, and 6 m/s × 3 s = 18 m. For uniform acceleration, displacement s = ((u + v)/2) × t. Here u = 5 m/s, v = 7 m/s and t = 3…

This is the taxonomic hierarchy for animals, going from the broadest group down to the most specific. Linnaeus built this ladder of ranks, and each rank contains one or more ranks below it.

Biofilms form on almost any moist surface, including implants and food equipment, and they are notoriously hard to kill with antibiotics.

Each statement says "no virus can", and each is disproved by well-known viruses.

Prokaryotic cells such as bacteria have no membrane-bound organelles, so they lack mitochondria. Prokaryotes have no true nucleus: their DNA lies in a region called the nucleoid, and they have no mitochondria, chloroplasts, endoplasmic reticulum or Golgi body.

Chalk, limestone and marble are all forms of calcium carbonate, CaCO₃. Chalk is a soft, porous rock built from the tiny shells of marine plankton.

The enzyme that makes most of the cell's ATP, ATP synthase, sits in the inner mitochondrial membrane along with the electron transport chain.

Leucoplasts are colourless plastids that store food: starch, oils and proteins. Plastids are found only in plant cells and some algae, and they are of three main kinds.