Biology Questions and Answers

Answer: A

The expression was coined by H. Spencer.

Herbert Spencer, the English philosopher, introduced the phrase 'survival of the fittest' in his Principles of Biology (1864), after reading Darwin's On the Origin of Species. Darwin later adopted it as a synonym for natural selection in the fifth edition of the Origin (1869).

So Charles Darwin is the trap: the theory was his, but the phrase was Spencer's. A.I. Oparin is known for his theory of the origin of life.

Answer: B

The keyed answer is Jenner.

Edward Jenner, who developed smallpox vaccination with cowpox material in 1796, called cowpox variolae vaccinae, 'smallpox of the cow', from the Latin vacca, cow. The word vaccine comes from his term.

Louis Pasteur later proposed extending 'vaccine' to all such preparations in Jenner's honour, but he did not coin it. Robert Koch is known for identifying the bacteria of tuberculosis and cholera, and Georges Kohler for monoclonal antibodies.

Answer: A

The primary function of ribosomes is protein synthesis.

Ribosomes, made of ribosomal RNA and protein, read the messenger RNA and join amino acids in the order it specifies to build proteins. That is why they are called the protein factories of the cell.

Energy production is the job of mitochondria, DNA replication happens in the nucleus, and lipid metabolism takes place mainly in the smooth endoplasmic reticulum.

Answer: C

Coordination and balance are the job of the cerebellum.

The cerebellum, at the back of the brain below the cerebrum, coordinates voluntary movements, maintains posture and balance, and fine-tunes motor activity. Damage to it causes clumsy, unsteady movement.

The cerebrum handles thinking, memory and voluntary action, the medulla oblongata controls involuntary functions such as breathing and heartbeat, and the thalamus relays sensory signals to the cortex.

Answer: B

The adult human skeleton has 206 bones.

A newborn has roughly 270 to 300 bones and cartilaginous pieces. Many of them fuse during growth, for example the bones of the skull, the sacrum and the coccyx, which brings the adult count to 206.

204, 208 and 214 are not standard counts. A person may have a few extra small bones, such as sesamoid bones or an extra rib, but the textbook figure for an adult is 206.

Answer: D

The part used is the Stem bark.

Quinine is an alkaloid extracted from the bark of the cinchona tree, native to the Andes and later grown in plantations in India and Java. Powdered cinchona bark was the standard remedy for malaria for centuries, and quinine was isolated from it in 1820.

The leaves, fruits and roots are not the commercial source; the alkaloids are concentrated in the bark of the stem and branches.

Answer: C

The hardest material in the body is Enamel.

Tooth enamel is about 96 per cent mineral, almost all of it crystals of hydroxyapatite (a calcium phosphate), which makes it harder than bone.

Dentin, the layer under the enamel, is less mineralised and softer. The pulp at the centre of the tooth is soft tissue holding nerves and blood vessels. Since enamel is in the list, 'None of these' is wrong.

Answer: B

The gas is Carbon monoxide.

Carbon monoxide binds to the iron of haemoglobin about 200 to 250 times more strongly than oxygen, forming carboxyhaemoglobin. The blood then cannot carry oxygen to the tissues, and a person exposed to it can die of oxygen starvation without noticing anything, since the gas has no colour or smell.

Carbon dioxide is carried by the blood in normal breathing and released in the lungs; methane is not taken up by haemoglobin; oxygen is what haemoglobin is meant to carry.

Answer: A

The Widal test is used to diagnose typhoid.

The Widal test is an agglutination test that detects antibodies in the patient's serum against the O and H antigens of Salmonella Typhi, the bacterium that causes typhoid (enteric) fever.

Cholera is diagnosed from stool samples, tuberculosis by sputum tests and the tuberculin (Mantoux) test, and HIV infection, which leads to AIDS, by tests such as ELISA.

A rising antibody titre in samples taken some days apart gives stronger evidence of typhoid than a single test.

Answer: B

USG stands for Ultrasonography.

Ultrasonography is the imaging technique that uses high-frequency sound waves and their echoes to produce pictures of internal organs and of the foetus during pregnancy. It uses no ionising radiation.

'Undersized gland' and 'Unsegmented gonads' are not medical abbreviations for USG, so 'None of the above' is wrong as well.

It is routinely used to examine the abdominal organs, the heart (as echocardiography) and the developing foetus during pregnancy.