Question

How was the nucleus discovered?

Answer 1

The nucleus is a membrane-bound organelle that contains genetic material (DNA) of eukaryotic organisms. It is an integral organelle in all cells.

Complete answer:
The nucleus of a cell is the site of many crucial cell activities. It has roles in transcription and replication processes. Since it is a large organelle inside the cell it can be easily identified and observed under the microscope. The main components of a nucleus are- phospholipid bilayer membrane, nucleoplasm, nucleolus and chromatin fibres. The nucleus is surrounded by a double membrane called the nuclear envelope. The nuclear envelope is discontinuous and has nuclear pore for passage of materials. There is a fluid inside the nucleus which is called the nucleoplasm. The nucleolus is a large densely stained, membrane-less nuclear body found in the nucleus. It is basically tandem repeats of ribosomal DNA that is DNA coding for ribosomal RNA.

Antonie van Leeuwenhoek in the 17th century was the first to hypothesize the presence of a lumen in the red blood cells of salmon. The nucleus was additionally depicted by Franz Bauer in 1804. Robert Brown was the first to discover and describe the nucleus in 1831. He was a Scottish botanist who examined orchids under the magnifying instrument when he noticed an obscure zone, which he called the areola or nucleus in the flowers’ external layer. After many years grafting experiments on Acetabularia, German biologist Dr Joachim Hammerling proved that the nucleus contains hereditary information and controls the development of organisms.

Note: Robert Brown is not to be confused with Robert Hooke. Robert Hooke was an English scientist who observed first cells from an organism from cork under a simple microscope in the 1600s. While Robert Brown discovered the nucleus in 18331.