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Title : Cells
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In this experiment, our objective is to investigate and describe the microscopic or basic structure of plant and animal cells and their differences. We can only observe the basic structure of cells because light microscope is used in this experiment. To investigate animal cells, we use cheek cell. It is discovered that these cheek cells exists in irregular shapes and are not organized. After staining the cheek cells with methylene blue, nucleus can be seen distinctly under the light microscope. To investigate plant cells, we use onion cells, while Elodea is used to investigate living plant cells. Unlike animal cells, plant cells are closely packed. They have more organized shapes compared to animal cells. This is due to the existence of cell walls in plant cells. In both animal cells and plant cells, nucleus can be seen distinctly. Nucleus is where all the cell activities are controlled. It also stores hereditary material. The difference between a living plant cell (Elodea) and a plant tissue (onion) is that the living plant cell contains chlorophyll, which is green in colour, and is responsible for absorbing ultraviolet light from the sun to undergo photosynthesis.
The basic unit of structure and function in living organisms is the cell. This is known as the cell theory, proposed jointly by Schleiden in 1838, and Schwann in 1839. The discovery was due to the fact that during the nineteenth century, there was dramatic improvements in the quality of lenses for use in microscopy and this eventually led to great interests in the structure of living organisms. An essential part of the cell theory is the idea, first proposed in 1855, that new cells come only from pre-existing cells. A cell can be thought of as a bag of chemicals which has the ability to survive and replicate themselves. Inside the bag, the chemicals differ in many ways from those outside...