Question

Nucleolus was discovered by
(a) Robert Brown
(b) Leeuwenhoek
(c) Robert Hooke
(d) Fontana

Answer 1

Hint: He was born on 15 April 1730 and was an Italian physicist who in 1780 discovered the water gas shift reaction. He also launched modern toxicology and investigated the living eye of the human.

Complete answer:
The nucleolus is the small, dense, spherical, and distinct structure present in the nucleus of eukaryotic cells. It is visible during the interphase of the cell division under the microscope. The main components are ribonucleic acid, deoxyribonucleic acid, and proteins which are formed from specific chromosomal regions called nucleolar organizing regions. In 1774, it was discovered by Felice Fontana.
The nucleolus nearly covers 25% volume of the nucleus. It is small in size compared to the nucleus and isn’t bound with cell membranes like in the nucleus. It doesn’t contain any chromosomes and is rich in RNA material. It helps in sensing cellular stress, assembling the ribosomes, and alteration of transfer RNA. We can say it mainly plays an important role in the production of ribosomes and the synthesis of proteins in the cells.
So, the correct answer is 'Fontana'.

Note: Antonie van Leeuwenhoek born in 1632 in the United Kingdom developed a microscope and Robert Hooke born in 1635 in the Netherlands was the first to use the word cell to explain the basic unit of life. Theodor Schwann born in 1810 in Germany proposed the cell theory. Antonie Philips van Leeuwenhoek who was a Dutch scientist who first observed the cell nucleus, but Robert Brown who was a Scottish botanist and paleobotanist observed it in 1833 giving it the name cell nucleus.