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Published byGerard Crawford Modified over 9 years ago
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Cells
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Robert Hooke -1665 In his book, entitled Micrographia, Hooke was the first to use the term cell From the Latin “cella” meaning “small chamber”
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Anton van Leeuwenhoek- 1675 A Dutch cloth merchant who became interested in studying cells Was the first to see and describe bacteria, sperm cells and protista
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Theodor Schwann (1838) – all animals are composed of cells Matthias Schleiden (1838) – all plants are composed of cells
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Rudolf Virchow (1856) “Omnis cellula e cellula” “where a cell arises, there a cell must previously have existed”
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Modern Cell Theory All organisms are composed of cells. Cell come from other cells. Cells are the smallest unit of structure and function in living organisms.
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Prokaryotic Cells Lack a true nucleus Size: 1-10 microns Include bacteria
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Basic Bacterial Cell
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Examples of Prokaryotes
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Eukaryotic Cells Have a true nucleus Size: 10-100+ microns Include plants, animals, fungi and protista
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Cell Membrane – surrounds the cell Cytosol – “cell liquid” Organelles – “little organs” Nucleus- control center
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Cell Membrane Regulates the passage into and out of the cell Provides protection Helps in cellular recognition of molecules
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Cytosol/Cytoplasm Cytosol: the liquid portion inside the cell membrane Cytoplasm: the cytosol and organelles, but not the nucleus
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Nucleus
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Contains DNA The cell’s “brain” or CPU DNA codes for protein production Surrounded by the nuclear envelope
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Cytoplasm Contains the cytosol and organelles
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Ribosomes Endoplasmic reticulum Golgi bodies or complex Lysosomes Mitochondria Chloroplasts
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Ribosomes
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Are the cell’s protein factories Read mRNA code as seen on the right Maybe free in the cytoplasm Or bound to the ER
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Endoplasmic Reticulum Comes from the Greek Endo = “within” Latin reticulum = “network.” A membrane network within the cytoplasm Two types: Rough – with ribosomes attached (RER) Or Smooth – with no ribosomes (SER)
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Rough ER Helps the ribosomes in the formation of proteins Used to transport proteins to other parts of the cell
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Smooth ER Functions include synthesis of membrane lipids & detoxification of drugs Liver cells contain large amounts of smooth ER
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Golgi Body
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Modify, sort, and package proteins from the ER for storage in the cell & secretion out of the cell
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Lysosomes
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Digestive sacs filled with enzymes Breakdown lipids, carbohydrates, and proteins into a form that can be used by the cell Digest worn out organelles
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Helps to recycle cellular structures Sometimes called “suicide sacs” Involved in rheumatoid arthritis Example…
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Mitochondria
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Converts chemical energy stored in food into compounds that the cell can use (cellular respiration) Contain their own DNA
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Chloroplasts
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Site of photosynthesis Contains the green pigment chlorophyll Helps to convert light energy, water, and carbon dioxide into sugars Also contain genetic information
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Endosymbiotic Theory States mitochondria and chloroplasts were once free living prokaryotic cells First proposed in the 1890s, but not supported until 1981 with the discovery of mitochondrial DNA Explanation…
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Vacuole Storage area for water, salts, proteins, and carbohydrates Many plants have a large central vacuole filled with liquid to support the plant
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Cell Wall The cell wall is a rigid structure that is found in plants, fungi, and bacteria cells It supports and maintains the shape of the cell. It is extremely strong.
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