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2.1 The Structure

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Title: Cell Structure and Function Author: Jerry Cook Last modified by: WRDSB Created Date: 1/19/2005 1:28:04 AM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: 2.1 The Structure


1
2.1The Structure Functions of Eukaryotic
Cells
2
Endoplasmic Reticulum
  • Moves substances between the cytoplasm and
    nucleus in a network of inter-connected, complex
    system of channels sacs (lumen)
  • Ribosomes (RNA proteins) synthesize protein and
    are either free-floating in the cytosol (proteins
    for use in cell) or attached to some ER (proteins
    excreted)
  • Two types of ER
  • Rough endoplasmic reticulum or RER
  • (ribosomes attached to the surface)
  • Smooth endoplasmic reticulum or SER
  • (no ribosomes attached to the surface)

3
Rough Endoplasmic Reticulum
  • Ribosomes attached to surface
  • Manufactures proteins for use in membrane or for
    excretion from the cell. Sends them in vesicles
    to the Golgi Apparatus.
  • Ribosomes, while still making proteins, differ in
    structure mechanisms between eukaryotes and
    prokaryotes.

4
RER Micrograph
5
Smooth Endoplasmic Reticulum
  • No attached ribosomes on the surface
  • Has enzymes that help build molecules of lipids
    (ie steroids phospholipids) for use in the
    membrane. Sends them in vesicles to the Golgi
    Apparatus.
  • SER also detoxifies drugs alcohol and produces
    hormones (ie sex hormones)

6
SER Micrograph
7
Endomembrane System
  • Includes nuclear envelope, ER and the Golgi
    Apparatus.
  • It synthesizes, modifies and transports cell
    products (ie protein)
  • The organelles are connected to each other by
    transport vesicles (membrane closed sacs for
    transport and storage)

8
Golgi Apparatus
  • Moves substances from vesicles of the ER through
    a network of complex system of channels sacs
  • Stores or modifies proteins (CHO chains) from
    vesicles
  • Involved in synthesis of
  • plant cell wall
  • Produces
  • lysosomes
  • Transports vesicles
  • to cell membrane for
  • excretion

9
Golgi Apparatus Function
  • 1. Molecules arrive in vesicles from ER
  • 2. Vesicles fuse with Golgi membrane
  • 3. Molecules may be modified by Golgi
  • 4. Molecules pinched-off in separate vesicle
  • 5. Vesicle leaves Golgi apparatus
  • 6. Vesicles may combine with plasma membrane to
    secrete contents

10
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11
Golgi Apparatus Micrograph
12
Lysosomes Peroxisomes
  • Contains digestive enzymes to breakdown
    macromolecules.
  • Lysosomes from GA and peroxisomes from ER
  • Peroxisome functions
  • catalyzing redox reactions
  • Breaks down toxic molecules
  • Contains catalase
  • Lysosome functions
  • Catalyze hydrolysis reactions
  • Breaks down old cell parts
  • Digests invaders

13
Vacuoles Vesicles
  • Membrane bound storage sacs (vesicles vacuoles)
    or transport sacs (vesicles only)
  • Larger vacuoles (ie central) found only in
    plants
  • Vesicles smaller more common in animals
  • Contents
  • Water
  • Food
  • Ions
  • Wastes
  • Macromolecules

14
Food Vacuole Micrograph
15
End Part 2
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