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Eukaryotic cell structure

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Divide by mitosis and meiosis. Ribosomes. Eukaryotic ribosome is 80S ... Mitosis & meiosis. Binary fission. Cell division. Eukaryotic Cells. Prokaryotic Cells ... – PowerPoint PPT presentation

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Title: Eukaryotic cell structure


1
Eukaryotic cell structure
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Structures External to Cell Wall
  • Flagella and cilia
  • Flagella
  • Cilia
  • Both used for motility cilia also used to move
    things across cell surface
  • Consist of 92 arrangement of microtubules and
    move in a wavelike manner

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  • Cell wall and glycocalyx
  • Do not contain peptidoglycan
  • Composed of less complex polysaccharides
  • Cellulose, chitin, glucan and mannan
  • Some eukaryotes lack a cell wall
  • Protozoa have a pellicle
  • Animal cells are covered by a glycocalyx
  • used for identification, cell strengthening and
    attachment
  • Carbohydrates are anchored to proteins and lipids
    of cell membrane

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Structures internal to the cell wall
  • Plasma membrane
  • Similar in function and structure to prokaryotes
  • Contain sterols
  • Can bring items into the cell by endocytosis
  • 2 types
  • phagocytosis (uses pseduopods)
  • pinocytosis (infolding of membrane)

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Cytoplasm
  • Cytosol is the fluid portion
  • 80 water with dissolved solutes (salts, glucose,
    proteins)
  • Cytoskeleton - complex internal structure
    consisting of exceedingly small rods called
    microfilaments and intermediate filaments and
    cylinders called microtubules
  • provides a structural support to the cell
  • movement in the cell
  • reinforce cell shape, anchor organelles

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  • Organelles - Membranous structures with specific
    shapes and specialized functions
  • Internal membranes of organelles compartmentalize
    the functions of the cell
  • Endomembranous system acts as a cellular factory
    for manufacturing cell products
  • increases surface area where reactions can occur
  • Some of the enzymes needed to drive reactions are
    part of the membranes
  • includes nuclear envelope, endoplasmic
    reticulum, golgi apparatus, lysosomes, vacuoles
    and plasma membrane

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Organelles
  • Nucleus - Contains DNA
  • Usually the largest structure in the cell
  • Has a nuclear envelope and nuclear pores and
    nucleolus where rRNA is synthesized
  • DNA is combined with special proteins histones
  • Chromatin
  • Chromosomes
  • Divide by mitosis and meiosis

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Ribosomes
  • Eukaryotic ribosome is 80S
  • chloroplasts and mitochondria have 70S ribosomes
    like prokaryotic cells
  • Ribosome subunits are made in the nucleolus and
    assembled in the cytoplasm
  • Free ribosomes synthesize proteins used in the
    cell
  • RER ribosomes synthesize secretory and membrane
    proteins

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Endoplasmic Reticulum (ER)
  • Network of cisterns, continuous with the nuclear
    envelope
  • Rough ER (RER)
  • Protein processing occurs inside cisterns
  • Smooth ER (SER)
  • Lipids are made in SER
  • Those in the sex organs produce steroid hormones
    like testosterone
  • Involved in muscle contraction
  • Detoxification in liver cells
  • Liver SER are also involved in carbohydrate
    synthesis

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Golgi Complex
  • Composed of stacks of flattened membranous sacs
    called cisterns
  • Shipping and receiving department
  • finishes, sorts and ships products os SER and RER
  • Involved in carbohydrate synthesis

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Lysosomes
  • Single membrane
  • Contains digestive enzymes
  • Phagosomes fuse with lysosomes forming
    phagolysosmes
  • White blood cells can digest bacteria in their
    phagolysosomes

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Vacuoles
  • Single membrane derived from the Golgi complex
  • Store nutrients and sequester harmful substances
  • Food vacuoles
  • Contractile vacuoles
  • Central vacuole

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Mitochondria
  • Powerhouse of the cell
  • Double membrane
  • Matrix
  • Primary site of ATP production in the cell
  • Circular DNA, 70S ribosomes, and divides by
    binary fission

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Plastids
  • Group of plant and algal organelles
  • Amyloplast (store starch), chromoplasts (color
    providing pigments), chloroplast (contain
    chlorophyll)
  • Chloroplasts
  • intermembrane space, thylakoid space, and stroma
  • Thylakoids stacked in grana contain chlorophyll
    needed for photosynthesis
  • Have 70S ribosomes and a circular strand of DNA
    and can reproduce by binary fission

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Endosymbiotic theory
  • Eukaryotic cells evolved from symbiotic
    relationships of prokaryotic cells living inside
    other prokaryotic cells
  • Evidence for this theory comes from the
    similarities of mitochondria and chloroplasts to
    prokaryotic cells

26
Centrosome
  • Composed of microtubules
  • Important for cellular division
  • Forms mitotic spindle which pulls chromosomes
    apart
  • Composed of two perpendicular centrioles
  • X shaped organelle found adjacent to nucleus

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Intercellular Junctions
  • plasmodesmata
  • tight junctions
  • desmosomes
  • gap junctions

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Extracellular Structures
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Intracellular Structures
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Genetic Structures
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Reproductive Processes
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