SCIENCE Revision- Cells

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To look at very small objects we use the microscope. The microscope can magnify things which

means

make them look a lot larger.

The object that we look at with a microscope is called the specimen. The specimen is placed on a glass slide and a coverslip placed over it

to

hold

the specimen in position and also to prevent it from drying.

When looking through a microscope two lenses are used. One is called the objective lens

positioned

right above the specimen. The other is called the eyepiece lens that a scientist will look through.

When using a microscope we usually need to know the power of magnification. It gives us an idea of how small an object is.

The total magnification viewed is the product of the magnification of the eyepiece lens and the magnification of the objective lens.
Cells can make new cells. One cell can divide into two new cells. This is called cell division.

The process of cell division goes through various stages.
First of all the cell nucleus splits into two.

A new cell surface membrane then forms in the middle and the cell divides.

The two new cells are called daughter cells and they are small to begin with. They will grow and get larger. They grow by getting

nutrition

from

food that is eaten. Once they have grown to full size they can also divide.

When cells start to divide in the wrong way and should

these divide

faster than they should cancer cells can develop.
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