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Cells Cells What are cells and are they all the same? How do we know they exist if we cannot see them?

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Presentation on theme: "Cells Cells What are cells and are they all the same? How do we know they exist if we cannot see them?"— Presentation transcript:

1 Cells Cells What are cells and are they all the same? How do we know they exist if we cannot see them?


3 Some Random Cell Facts  The average human being is composed of around 100 Trillion individual cells!!!  It would take as many as 50 cells to cover the area of a dot on the letter “ i ” WOW!!!

4 os170/170_5/Chk_cell.JPG 6/7/14673604/7521071_orig.jpeg?0 get/I0000ITnK5jj64zM/s/500/400/PX09-003e.jpg vecell.jpg e1203/lightwise120300022/12668156-bacteria-and- bacterium-cells-floating-in-microscopic-space.jpg

5 Anton van Leeuwenhoek  In the mid 1600’s Leeuwenhoek is thought of as discovering the first practical microscopes.  Leeuwenhoek in 1674 was the first to see 1. bacteria, yeast, and plants 1. bacteria, yeast, and plants 2. life in a drop of water 2. life in a drop of water 3. circulation of blood corpuscles in 3. circulation of blood corpuscles in capillaries capillaries

6 Discovery of Cells  1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork (dead cells from oak bark).  He described the cells as tiny boxes or a honeycomb  He thought that cells only existed in plants and fungi

7 Development of Cell Theory  1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells  1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.

8 Development of Cell Theory  1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.

9 The Cell Theory Complete The 3 Basic Components of the Cell Theory were now complete: 1. The cell is the basic unit of life in all living things. 2. All organisms are composed of one or more cells. 3 All cells are produced by the division of preexisting cells.

10 Scientists have found two basic types of cells: 1. Prokaryotic cells are those that have no membrane around their nuclear material. Prokaryotic vs. Eukaryotic Example include bacteria and pond scum cells. Involved in -  cell division

11 Bacterial Cells Unlike plant and animal cells, bacterial cells are prokaryotic. They do not have membrane- bound organelles, nor nuclei. They do have: ribosomes, a single chromosome, a cell wall, and cytoplasm. Reproduction: asexual or sexual? Good and bad bacteria?

12 2. Eukaryotic cells have a membrane bound nucleus. Animal and plant cells are eukaryotic.

13 Animal Cells   Animal cells are eukaryotic   Every cell in your body is constantly active and has a specific function. For example, a nerve cell has a job that is much different than a muscle cell. Each cell has several structures inside, and each structure has a specific job. These structures are called organelles.

14 Plant Cells (eukaryotic) The major difference between a plant cell and an animal cell is that plant cells have cell walls. A cell wall is a rigid structure outside the cell membrane that supports and protects the plant cell.

15 Plant cells continued: 2. Plants also differ from animal cells because they can make their own food. 3. Organelles called chloroplasts convert light energy into chemical energy in the form of sugar. 4.One of the chemicals in chloroplasts, chlorophyll, traps light energy

16 Organization of Cells   A one-celled organism (unicellular) performs all of life’s functions by itself An example is bacteria   A multicellular organism, however, does not work independently. Each cell depends on other cells to carry on all of life’s functions. In a multicellular organism, cells are organized into tissues.   Tissues are groups of similar cells that do the same sort of work. Cells->Tissues- >Organs -> Organ system -> Organism

17 1. 2. 87e3c.jpg 3. s%20400x.jpg 4. What kind of cells did you see?

18 5. 6. Blood-Cells-Pharmacyrepublic-Kidney-Failure-Blog.jpg 7. blr_mq1wexvOIo1s4sgqko6_r1_1280.jpg 8.

19 All cells contain????  Cell membrane  DNA  Cytoplasm  Ribosomes

20 Differences in Animal and plant cells (eukaryote) ? Animal  Centrioles  Lysomes  Irregular shape Plant  Chloroplasts  Cell Wall  Central vacuole  Rectangular shape

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