General Science Mixed Quiz: Set 160

Lime water is a clear solution of calcium hydroxide, and carbon dioxide reacts with it to form insoluble calcium carbonate, which turns the solution milky.

Phycology, also called algology, is the study of algae, the simple photosynthetic organisms that range from the single-celled Chlamydomonas to the large brown seaweeds, and it covers their classification and their uses as food, fertiliser and a source of agar.

Muscle cells are packed with the contractile proteins actin and myosin, whose filaments slide over each other to shorten the cell and produce movement.

The adult column is counted as seven cervical vertebrae in the neck, twelve thoracic vertebrae bearing the ribs, five lumbar vertebrae in the lower back, one sacrum and one coccyx, giving twenty-six bones in all.

The acid-secreting cells of the stomach, called oxyntic or parietal cells, release hydrochloric acid, which protein digestion in the stomach depends on.

The acrosome is a cap-like structure over the sperm nucleus filled with enzymes that digest the layers around the egg so that one sperm can fuse with it.

The corpus callosum is a thick band of nerve fibres that joins the two cerebral hemispheres, so it belongs to the forebrain, not the hindbrain.

A person of group AB carries both the A and the B antigen on the red cells, and because the body does not make antibodies against its own antigens, the plasma carries neither anti-A nor anti-B; blood of any group can therefore be transfused into such a person, who is…

Using the lens formula with sign conventions, the object is found to be 10 cm from the lens, and the magnification v/u comes to 0.5.

The order is plasmid (1952), DNA double helix (1953), DNA fingerprinting (1984) and the cloning of Dolly (1996). Joshua Lederberg coined the word "plasmid" in 1952 for genetic material that lives outside the chromosome; plasmids later became the main vectors of genetic engineering.

Water gas is made by passing steam over red-hot coke, and the reaction C + H₂O → CO + H₂ gives carbon monoxide and hydrogen in roughly equal volumes.

The adult human skeleton has 206 bones, of which 80 belong to the axial skeleton, that is the skull, vertebral column and chest, and 126 to the appendicular skeleton of the limbs and girdles.

This is false because viruses have no chlorophyll, no cell organelles and no metabolism of their own, so they cannot make food in any way.

Galvanisation is the coating of iron or steel with zinc, usually by dipping the article in molten zinc, and it protects the iron twice over: the layer keeps out air and moisture, and because zinc is the more reactive metal it corrodes in place of the iron even where the…

. A light-year works as a unit of distance only because light in a vacuum always travels at the same speed, so the distance it covers in a year is fixed.

At a fixed speed v, centripetal acceleration equals v²/r, so a larger radius gives a smaller acceleration. An object moving in a circle at constant speed is still accelerating, because its direction keeps changing.

Carbon monoxide binds to the haemoglobin of red blood cells to form carboxyhaemoglobin, so the blood can no longer carry oxygen to the tissues.

The skin is the largest organ of the human body by both surface area and weight, and it is the organ of touch; it is made of an outer epidermis and an inner dermis that carries blood vessels, nerve endings, hair follicles, sweat glands and sebaceous glands.

In anodizing the clean aluminium article is indeed the anode, but oxygen is released at the anode, not at the cathode; hydrogen is released at the cathode.

A true fruit forms from the ovary alone, but in the apple and the pear the thalamus grows, becomes fleshy and forms the greater part of the edible tissue, while the ovary makes only the core; such a fruit is called a false or spurious fruit, and the specific type…