Page 16 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Stages of development

The development of cell biology is the result of the growth in
the field of research of microscopes. A compound microscope
magnifies an object only 2000 times (maximum) its size. Electron
microscopes utilize electrons instead of a light source (Fig 1.6).
With the emergence of the electron microscope, which magnifies
objects million times clearly we got a thorough understanding
of microscopic cell organelles.

Fig. 1.5
A microscope of the
earlier times

The history of the microscope is the
best evidence showing how science
enables the development of
technology and how technology
enables the development of science.
It would be very interesting to collect
information and pictures of various
microscopes from the simple
microscope that helped Robert
Hooke to observe tiny chambers of
life to the advanced microscope that
enabled us to understand the secrets
of life within those tiny chambers.
Organise an exhibition including all
the collections.
Fig. 1.6
Electron microscope

Nucleus – the regulatory centre of the cell

Isn’t it necessary to control and coordinate innumerable life
activities in the cells? The various proteins produced in the
cell play a major role in regulating various activities in the cell.
The synthesis of proteins is under the control of genes in the
chromatin reticulum in the nucleus. Hence the nucleus is
considered as the regulatory centre of the cell.
Fig. 1.7
Observe the illustration 1.3. Nucleus

Basic Science VIII 15