The document discusses cells and microscopes. It summarizes that cells are the basic units of life and microscopes allow us to study cells. There are two main types of microscopes - compound microscopes, which use two lenses and are used in schools, and electron microscopes, which do not use lenses and can study extremely small objects. The discovery of cells took a long time because early scientists did not have powerful microscopes to observe cells directly.

1. Chapter – 2
The Cell
INTRODUCTION
What is Cell?
Cell is the basic building blocks of living organisms.
Cells are also called as basic unit of life.
MICROSCOPES
Microscopes are the most important instruments that have helped us to discover and study cells. A microscope is an
instrument that is used to view small objects by making them appear larger. Different types of lenses are used in microscopes to
make the objects appear larger.
Two Dutch spectacle, Zacharias Janssen and his father, Hans Janssen, are believed to be the inventors of the microscope.
Types of Microscopes
The simple microscope uses only one lens and works like a magnifying glass.
The compound microscope uses two lenses and give a more magnified image than the simple microscopes does.
Compound microscopes are used in school laboratories.
A third kind of microscope is also used; it is called the Electron microscope. It does not use any lens. It is used in
laboratories and can be used to study extremely small objects.
Hence, the two type of microscopes are Compound microscope and Electron microscope.
THE DISCOVERY OF THE CELL
The discovery of cell took a long time to be believed since most scientists did not have the tools to study life like
we do today.
Robert Hooke: He was the first person to observe and name cells.
Antonie Van Leeuwenhoek: He made and used hundreds of simple microscopes.