The nucleus
In both activities this was the first thing the stain brought out — the chief organelle a cell has.
Figure to be added
The nucleus
The nucleus is the chief organelle a cell has. It is covered by the nuclear membrane, and it contains the nucleolus and chromatin material.
The main function of the nucleus is to control the life processes of the cell.
From chromatin to chromosomes
During cell division this chromatin material becomes visible as chromosomes. It is the chromosomes that store the genetic material and that pass on inherited characteristics from one generation to the next.
The number is peculiar to the species
The number of chromosomes present in a living species is peculiar to that species.
| Species | Number of chromosomes |
|---|---|
| Human | 46 |
| Frog | 26 |
| Rice plant | 24 |
The number says nothing about complexity
Rice having 24 and a human 46 does not make a human twice as complex as a rice plant. A chromosome number is only how many packages the genetic material is divided into — it tells you which species a cell belongs to, not how advanced that species is.