Biology Quiz 4

Iodine test is used to detect starch (carbohydrates). When starch is present, the iodine changes from brown to blue-black or purple.

Kidney can be taken from a dying person who has the cessation of neurological function only. Tissues such as cornea, heart valves, skin, and bone can be donated in case of natural death but vital organs such as heart, liver, kidneys, intestines, lungs, and pancreas can be donated only in the case of 'brain death'.

The kidney is the organ that excretes water, fat and various catabolic wastes. The kidneys remove waste products called urea from the blood through tiny filtering units called nephrons. There are about one million nephrons in each kidney.

Genetically modified (GM) foods are foods derived from organisms whose genetic material (DNA) has been modified in a way that does not occur naturally. GM is a technology that involves inserting DNA into the genome of an organism. To produce a GM plant, new DNA is transferred into plant cells.

Gregor Mendel (1822-1884) discovered the basic principles of heredity through experiments with pea plants, long before the discovery of DNA and genes.

The rock dove, rock pigeon, or common pigeon is a member of the bird family Columba-livia (doves and pigeons).

Atherosclerosis is a narrowing or blockage of artery walls usually caused by the buildup of fatty material called plaque. Coronary artery disease is a narrowing or blockage of coronary arteries. Hypertension, also known as low blood pressure, increases the risk of a heart attack. Hypotension (or low blood pressure) is a blood pressure under 90/60 mm/Hg.

When the radius of blood vessels decreases, their capacity to hold blood is reduced, allowing more blood to return to the heart from which it is pumped into the arteries. As a result, blood pressure increases.

Leukaemia is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation of blood cells, usually white blood cells (leukocytes).

Commercially important cotton fibres are epidermal hairs of seeds. The cotton is found to grow around the seed coat of the cotton (Gossypium) plant.