The Cell

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The Cell

• Chapter 7.1, 7.3

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• Def. according to cell theory
• All organisms are made of cells
• Basic unit of structure
• All cells come from preexisting cells
• Cytology The study of cells
• 60 trillion in adult human
• 20 trillion red blood cells in adult human

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Types of Cells

• Prokaryotic has no nucleus or membrane-bound
  organelles
• Only bacteria
• Smaller (1-2µ)
• Eukaryotic has a nucleus and membrane-bound
  organelles
• Can be single celled organism or multicellular
• Larger cells (gt10µ)

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Organelles

• Nucleus
• Contains DNA
• Usually in the form of chromatin (strands,
  loosely packed can condense to form
  chromosomes)
• Controls production of proteins (and thereby
  controls all cell activities)
• Enclosed by nuclear envelope
• Membrane that regulates traffic into and out of
  nucleus
• Nucleolus inside
• Synthesizes ribosomes
• Up to 10,000 per minute

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Diagram on pg 181 - Glencoe
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• The Cytoplasm everything outside of the nucleus
• Cytosol the clear, fluid-like medium that
  surrounds all organelles

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Ribosomes

• Site of protein synthesis
• Found in all cells
• May be found attached to other organelles
  (endoplasmic reticulum), or free in cytoplasm
• 2 subunits (large and small)
• No membrane surrounding the organelle
• Differ in eukaryotes vs. prokaryotes
• Tetracycline, streptomycin disrupt prokaryotic
  ribosomes (antibiotics)

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• Endoplasmic Reticulum (ER)
• A membranous network
• Rough ER
• Studded by ribosomes
• Secretory proteins manufactured (ex. Antibodies,
  hormones)
• Alters, packs the protein in a vesicle, and sends
  it to the Golgi Apparatus

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• Endoplasmic Reticulum (ER)
• Smooth ER
• Manufactures lipids
• Detoxifies substances

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• Golgi apparatus
• Chemically alters products from the ER, sorts it,
  stores it, and ships it
• Flattened, membranous sacs

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• Vacuoles
• Membrane enclosed sacs
• Called vesicles when little
• Functions
• Food vacuoles from phagocytosis (cell eating)
• Contractile vacuoles pump out water
• Central vacuole (plant) storage

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p183 Glencoe
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• Plasma Membrane
• Surrounds all cells
• Selectively permeable
• Cell Wall (not in animal cells)
• Protects, and supports
• Outermost covering (exterior to plasma membrane)
• Composed of cellulose in plant cells
• Very porous, does not select which molecules can
  enter the cell

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Plasma Membranep179 Glencoe
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Cell Wall
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Centrioles

• Involved in cell division
• Not found in plant cells

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• Mitochondria
• Site of cellular respiration (glucose ?useable
  energy)
• Inner membrane has many folds

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p185 Glencoe
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• Chloroplasts (Plant and Algal cells)
• Sites of photosynthesis
• (sun energy and CO2 ?glucose, oxygen and water)
• Contain chlorophyll (green) among other pigments

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p 184 Glencoe
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• Lysosomes
• Membrane enclosed bag containing enzymes
• Digests food, wastes
• Made by rough ER with Golgi processing
• Suicide sacs -can destroy entire cell
• Tail of the tadpole

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