The Cell

•What is a cell and how do we know cells exist?

•Are human cells, animal cells, and plant cells all the same?

Why is it important to understand the cell and how it functions?

•Look closely at the skin on your arm. Can you see that it is made of cells?

•Of course not! Cells are much too small to see with your eyes.

•Now look at one square centimeter of your arm. That square centimeter contains about 100,000 skin cells.

•Cells are so small that they weren’t even discovered until the invention of the microscope

​•In 1663, English scientist Robert Hooke (1635–1703) took a thin slice of cork and placed it under a microscope that he built.

•He observed units resembling small square structures and called each of the square structures a cell because they reminded him of tiny rooms.

•Later Anton van Leeuwenhoek (1632–1723) built a microscope with better magnification and used it to observe the nuclei, single-celled protists, blood cells, and bacteria

•Later, the electron microscope was developed. It can magnify up to 500,000 times and has high resolution

•It has enabled scientist to observe more details of the internal structures of the cell

A cell contains special structures for different cell functions. Some can be seen under a light microscope

•A cell is the basic unit of structure and function in a living thing.​

All living organisms are made up of tiny units called cells

•Some organisms like amoeba are composed of only a single cell. They are said to be unicellular

•Multicellular organisms like humans, cows, insects, maize etc are composed of many cells

•Organisms have different type of cells for different functions, but they all share characteristics of living things

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•Use a magnifying glass/magnifying glass APP to observe,

• Your palm

  Leaves

• Skin of another student

•Are they smooth?​

​•Draw and label the parts of a microscope

·Prepare and observe temporary slides of plants cells under the light microscope.

·Draw and label parts of the plant cells seen under the light microscope.

·Observe permanent slides of plant and animal cells under a light microscope and compare the observable structures.

·Discuss the function of various parts of plant and animal cells.

·In case a microscope is not available, Watch a video on how a microscope is used to observe plant cells

​The Plant Cell