Biology Questions and Answers

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.

Answer: C

The mitochondrion is the powerhouse of the cell.

It carries out the Krebs cycle and the electron transport chain, producing most of the cell's ATP. Its inner membrane is deeply folded into cristae to give the enzymes room, and it has its own DNA and ribosomes.

Answer: A

Pollination is the transfer of pollen from the anther to the stigma.

It is the transfer itself, not what follows: germination of the pollen grain and growth of the pollen tube down the style come afterwards, and fertilisation is a separate event again.

Answer: C

Cell division takes place by mitosis, and by meiosis in the formation of gametes.

Mitosis produces two daughter cells genetically identical to the parent, and is how an organism grows and repairs itself. Meiosis halves the chromosome number and produces four genetically varied cells.