Cell Theory: Prokaryotes And Eukaryotes

Cells are smallest building block of all living things. They are necessary to make any living organism. Cells in every organism are not going to be same. The cell theory states that all organisms are composed of cells, cells are the basic unit structure and function in organisms, and cells come only from preexisting cells because cells are self-reproducing. Cells are not created equal. They come in a variety of shapes and sizes. There are two major types of cells: prokaryotes and eukaryotes. Prokaryotic cells have circular DNA, organelles that are non-membrane bound, and have no nucleus. Bacteria is a prokaryotic cell. Examples of bad bacteria are e. coli, cholera, salmonella, campylobacter, and staphylococcus. Some organelles in bacteria are

Eukaryotic cells have existed for 1.5 billion years. They are considered to be younger than prokaryotic cells. They have a nucleus, linear DNA contained inside nucleus, and organelles that are both non-membrane bound and membrane bound. There are two major groups of eukaryotic cells: animal cells and plant cells. Animal cells have linear DNA, lysosome, mitochondria, nucleus, golgi apparatus, nucleolus, vacuole, smooth endoplasmic reticulum, and rough endoplasmic reticulum. They are the only eukaryotic cells that contain the flagellum and centriole. In addition to the organelles of the animal cell besides the centriole and flagellum, the plant cells have a cell wall and chloroplasts. Each organelle is very important to every cell. The nucleus controls everything in the cells. They tell everything in the cell what to and when to do it. It is like the brain of the human body. Prokaryotes are far less complex than eukaryotes. They are simpler and smaller. Although prokaryotes do not contain the nucleus, they still carry out the same functions as a

Eukaryotes are the only cells with the nucleus. They are generally larger than a prokaryote. They show many more structure. Some eukaryotes live as unicellular organisms, others form large multicellular organisms such as plants, animals, fungi, and protists. We would not be able to see any of these types of cells with the unaided eye. The only reason we know about the cell is because the microscopes lets us observe it. Microscopes have been used since the mid-1600s to explore cells. The microscope has evolved since then. From early microscopes to electron microscopes and scanning probe microscopes. With these microscopes, scientists were able to observe the cell in a variety of ways. They started to understand what the cell was made up of. On a regular microscope, there are three objectives which are each different magnifications so adjustments can be made for clearer