General Science Mixed Quiz: Set 138

The sour taste of tamarind comes from tartaric acid, not oxalic acid, so this statement is not correct. Many natural acids give foods their sour taste.

The stapes, shaped like a stirrup, is the innermost of the three ossicles of the middle ear and is the smallest bone in the human body, measuring only a few millimetres; the smallest muscle of the body, the stapedius, is attached to it.

Xylem is made of more than one type of cell working together, which is what makes a tissue complex. Plant permanent tissues are of two kinds.

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.

In photosynthesis, the oxygen released into the air comes from water molecules that are split using light energy. Photosynthesis takes place in the chloroplasts of green plants.

A barometer measures the pressure of the atmosphere, traditionally by balancing it against a column of mercury. It is also used for forecasting weather, because a sudden drop in pressure signals an approaching storm, and for finding altitude, since pressure falls as one rises.

This is wrong, because a compound is a pure substance with a fixed composition throughout. Pure substances are of two kinds, elements and compounds.

A semiconductor has a small forbidden energy gap, so heating supplies thermal energy that pushes more electrons from the valence band into the conduction band, creating more electron-hole pairs.

The tapeworm is an animal, and animal cells have no cell wall, only a cell membrane. A rigid cell wall lies outside the cell membrane in plants, fungi, most bacteria and many protists, giving the cell shape and protection.

Calorific value is the heat released on completely burning one gram of a substance, and among the four foods listed ghee has the highest, because it is almost entirely fat.

The flying fish is a bony fish with a backbone, gills, scales and fins, so it belongs to the class of fishes; it only glides over the water on its large, wing-like pectoral fins.

Chlamydomonas is a unicellular, flagellated member of the Chlorophyceae, the green algae, in which chlorophyll a and b give the plant its grass-green colour and the food is stored as starch.

This is false, because most antibiotics, starting with penicillin, come from microbes. Alexander Fleming discovered penicillin in 1928 from the mould Penicillium notatum, which stopped the growth of bacteria around it.

The deficiency of adenosine deaminase destroys the immune system because the enzyme is needed for the normal working of lymphocytes, and in 1990 lymphocytes of a girl with this disorder were grown outside the body, given a functional gene and returned to her blood; since those cells are not permanent…

Bronchioles are the fine branches of the airways in the lungs, and their walls have no cartilage. Cartilage is a firm but flexible connective tissue.

In a class 3 lever the effort is applied between the fulcrum and the load, so the effort always sits nearer the fulcrum and its arm is the shorter of the two.

Genetic engineering uses recombinant DNA, cloning and gene transfer, and restriction enzymes cut DNA at specific sites; but they do not unzip DNA into two strands, so statement 3 is wrong.

The American physicist Murray Gell-Mann proposed quarks in 1964 and gave them their name. Gell-Mann, and independently George Zweig, suggested that protons, neutrons and other such particles are built from smaller units.

Mycology is the study of fungi, the group that includes moulds, yeasts, mushrooms and the rusts and smuts that attack crops, and a specialist in it is called a mycologist.

Heavy water is D₂O: two atoms of deuterium joined to one atom of oxygen. Deuterium is the isotope of hydrogen with one proton and one neutron in its nucleus, so it is about twice as heavy as ordinary hydrogen.