The Cell
History of Cells In 1665, English scientist Robert Hooke used the first compound light microscope to see plant tissues He viewed several thin slices of cork He called the small chambers within the cork cells after the latin word for small rooms cellos The term is still used today
Van Leeuwenhoek 1674- used be5er lenses than Hooke so saw more detail 1 st person to document seeing living cells as he looked at pond water animalcules 1 st crude microscope made by the Dutchman
Cell Theory Schleiden, a German scientist concluded from his research that all plants were composed of cells. (1838) His statements, paired with Schwann would become part of the cell theory
Cell Theory Schwann, a German physiologist concluded from his research that all animals are composed of cells (1838) His work, coupled with Schleiden became part of the cell theory
Cell Theory Rudolf Virchow was a German physician Stated all cells come from other cells He was credited for writing the Cell Theory. (1838)
The Cell Theory All living things are composed of cells Cells are the basic unit of structure and function New cells are produced from existing cells
Cell Theory Controversy Very controversial because it went against current belief in spontaneous generation. Spontaneous Generation Article Assignment
We talked about the history of cell discovery in our previous lecture. Why do you suppose all of these discoveries were made outside of the United States?
Cell divisions Prokaryotes Eukaryotes
Most simplistic cell Have no nucleus Have no organized membrane bound organelles Primitive structure Single cell only Examples are bacteria both disease causing and helpful Prokaryotes
Prokaryotes
Have a nucleus Contained organized membrane bound cell organelles Complex cells Single or multicellular Examples are all living cells that are found in plants, animals, protists, and fungi Eukaryotes
Can you name these eukaryotes?
Cell Shape Cell shape helps Determine function form fits function
Animal Cell
Plant Cell
Cell organelles Complex structures found in eukaryotes Each carry out a specialized cell function Location within the cell aids in its function Number of organelles depends on the variety of cellular responsibility
Nucleus Information processing center Stores the cell s hereditary material or DNA (chromatin) Coordinates the cell s activities (including growth and reproduction)
Nucleolus Located inside the nucleus Stores genetic material (RNA) for protein synthesis
Mitochondria Contains a double membrane inner layer Powerhouse of the cell Takes in fuel from sugars and fats Harvests energy with oxygen to produce ATP (highly usable energy) Where in your body would find cells with a large amount of mitochondria? Why?
Golgi Apparatus The distribution and shipping department Modifies proteins and fats and prepares them for export outside of the cell Found near the cell membrane
Endoplasmic Reticulum Network of sacs that manufactures and transports chemical compounds for use inside and outside the cell It connects to the nucleus to provide a pipeline to the outside of the cell
Ribosome Site of protein production Located on the endoplasmic reticulum or free floating in the cytoplasm
The chemical erythromycin is effective in stopping protein synthesis in bacterial cells, but it does not stop protein synthesis in human cells. Suggest a possible use for erythromycin.
Lysosome Lysosomes break down cellular products and debris from outside the cell Digests worn out cells and cell parts
Centriole Bundles of filaments that aid in the process of cell division Found only in animal cells
Vacuole Stores compounds for the cell Aids in plant growth The single organelle is found near the center of the cell
Cytoskeleton Allow the cell to change shape Give the cell support and structure
Cell Membrane Outer membrane of the cell to protect its contents Regulates the molecules that pass in and out of the cell (selectively permeable) Give the cell its shape
Chloroplast Site of photosynthesis Converts light energy into chemical energy Found only in plant cells
Cell Wall Rigid wall outside of the plasma membrane Protects the cell and its contents Found only in plant cells Made of cellulose
Cilia and Flagella flagella Used for locomotion of the cell Moves materials past the cell Cilia on a paramecium
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