General Science Mixed Quiz: Set 101

The liver needs vitamin K to make prothrombin and several other clotting factors, so a deficiency of it lengthens the clotting time and causes bleeding; this is why a newborn is given vitamin K and why the vitamin is sometimes called the anti-haemorrhagic vitamin.

Meiosis makes gametes that differ from one another, and fertilization joins a gamete from each of two parents, so every offspring gets a new mix of genes.

Golden Rice carries genes that let the grain make beta carotene, the orange pigment that the human body converts into vitamin A, and the colour of the grain gives the variety its name; the aim is to reduce night blindness and childhood blindness in populations whose diet is mainly rice.

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.

X-rays are electromagnetic waves made of photons, which carry no electric charge, so electric and magnetic fields cannot bend them.

This soil bacterium naturally transfers a part of its tumour inducing plasmid, called the Ti plasmid, into the cells of a dicotyledonous plant and causes crown gall disease; genetic engineers disarm the plasmid, insert the gene they want and use the bacterium as a vector, which is why it is…

One mole of N₂ weighs 28 g, so half a mole weighs 14 g. A nitrogen molecule is made of two nitrogen atoms, each with an atomic mass of 14 u, so its molecular mass is 28 u and its molar mass is 28 g per mole.

A beam seen from the side is visible only because tiny particles send some of its light sideways. Light travelling in a straight line cannot enter our eyes unless something redirects it towards us.

In 1796 Edward Jenner used matter from a cowpox sore to protect a boy against smallpox, the first vaccination in the modern sense, and the word vaccine comes from vacca, the Latin for cow.

The anther is the top part of the stamen, the male organ of a flower, and pollen grains form inside it.

The polymerase chain reaction repeats three steps, denaturation at a high temperature, annealing of short primers and extension of the new strand, so the enzyme must survive near boiling water; Taq polymerase, obtained from the bacterium Thermus aquaticus of hot springs, does exactly that and lets a single DNA segment…

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

X-rays have wavelengths of roughly 0.01 nm to 10 nm, so 1 nm sits right inside the X-ray band. The electromagnetic spectrum runs, from the shortest wavelength to the longest, as gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves and radio waves.

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.

Anhydrous sodium carbonate is Na₂CO₃, and 2 × 23 + 12 + 3 × 16 = 106 u. Formula mass is the sum of the atomic masses of all the atoms in one formula unit of an ionic compound.

The pericycle is a layer of cells around the vascular cylinder of the root and stem; it is not part of xylem or phloem.

BCG stands for Bacillus Calmette-Guerin, a live but weakened strain of the bovine tuberculosis bacterium, and in India it is given soon after birth under the Universal Immunisation Programme, mainly to prevent the severe forms of childhood tuberculosis.

Dolly was a sheep produced at the Roslin Institute in Scotland in 1996 by the technique of somatic cell nuclear transfer, in which the nucleus of an udder cell of one sheep was placed in an egg whose own nucleus had been removed, so the lamb carried the genes of…

Electromagnetic waves are transverse, not longitudinal, so this statement is false. In an electromagnetic wave the electric field and the magnetic field oscillate at right angles to each other and both at right angles to the direction in which the wave travels.

Only this split of boron-10 and boron-11 gives an average atomic mass of 10.81. The relative atomic mass of an element is the average of its isotopes' masses, each weighted by how common it is.