Biology Questions and Answers

Answer: C

Food wrapped in newspaper can be contaminated with lead.

Printing inks have contained lead-based pigments and driers, which transfer to oily food in contact with the print. Lead accumulates in the body and damages the nervous system, especially in children.

Answer: D

Radioactivity is the spontaneous emission of all three: alpha particles, beta particles and gamma rays.

An alpha particle is a helium nucleus, a beta particle an electron emitted from the nucleus, and a gamma ray high-energy electromagnetic radiation. Becquerel discovered the phenomenon in uranium in 1896.

Answer: C

Acetylsalicylic acid is aspirin.

Introduced by Bayer in 1899, it relieves pain and fever and reduces inflammation by inhibiting the cyclo-oxygenase enzymes that make prostaglandins. In low doses it thins the blood and is taken to prevent heart attacks.

Answer: A

Eggs contain no vitamin C.

The yolk supplies protein, fat, vitamins A, D, E, K and most of the B group, and iron. Vitamin C is one of the very few nutrients an egg lacks entirely, which is why it must come from fruit and vegetables.

Answer: B

Oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases are the six classes of enzymes.

The classification is by the reaction catalysed and is the basis of the EC numbering system. Enzymes are proteins, but not every protein is an enzyme.

Answer: C

Plants of average temperature and moisture are mesophytes - the great majority of land plants.

They need no special adaptations for drought or waterlogging: ordinary broad leaves, a moderate cuticle and a fibrous root system. Most crops and garden plants are mesophytes.

Answer: A

The largest fruit is that of Lodoicea, the coco de mer or double coconut of the Seychelles.

A single seed can weigh 25 kg and takes six to seven years to ripen. The plant with the smallest flowering is Wolffia, at under a millimetre.

Answer: D

The potato is a modified stem - a tuber formed at the tip of an underground branch.

Its eyes are buds with scale leaves beside them, which is what identifies it as a stem. Carrot and sweet potato are modified roots and the coconut is a fruit.

Answer: C

Cancer is caused by uncontrolled mitosis.

Mutations in the genes regulating the cell cycle release a cell from the controls that normally stop division, so it multiplies without limit and its descendants form a tumour. Meiosis produces gametes and has nothing to do with it.

Answer: C

Bidi wrappers are made from tendu leaves, from the tree Diospyros melanoxylon.

The leaves are collected from forests in central India, and tendu collection is a major seasonal livelihood for forest-dwelling communities in Madhya Pradesh, Chhattisgarh and Odisha.