The Cell


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The Cell

  1. 1. The Cell <ul><li>All Living things are composed of cells </li></ul><ul><li>All Cells have/contain the following: </li></ul><ul><li>Cell Membrane - Lipid Bilayer - Separates inside from outside </li></ul>
  2. 2. Cytoplasm <ul><li>Cytoplasm - everything but DNA/Nucleus </li></ul>
  3. 3. Two Cell types <ul><li>         Prokaryotic Cells </li></ul><ul><ul><li>1.       Primitive cells – include bacteria </li></ul></ul><ul><ul><li>2.      No nucleus </li></ul></ul><ul><ul><li>3.      No Membrane-bound organelles </li></ul></ul><ul><ul><li>4.      Very Small 1-10 micrometers </li></ul></ul><ul><ul><li>5.      Single Strand of Circular “naked” DNA </li></ul></ul><ul><ul><li>6.      Contain Ribosomes </li></ul></ul>
  4. 4. Typical Prokaryotic Cell
  5. 5. Eukaryotic Cells <ul><li>Eukaryotic Cells </li></ul><ul><li>1.       Contain a Nucleus which protects DNA / Chromosomes </li></ul><ul><li>2.      Much larger than prokaryotic cells </li></ul><ul><li>3.      Have many different types of Membrane bound organelles - compartmentalization = efficiency </li></ul>
  6. 6. Eukaryotic Cells Animal Eukaryotic Cell Plant Eukaryotic Cell
  7. 7. Organelles <ul><li>Membrane-Bound organelles only found in Eukaryotes </li></ul><ul><li>Localize Chemical Reactions making the cell far more efficient </li></ul>
  8. 8. Major Organelles of the Eukaryotic Cell <ul><li>The Nucleus </li></ul><ul><li>“ eukaryotic” means “true nucleus” </li></ul><ul><ul><li>Contains & protects the cell’s DNA </li></ul></ul><ul><ul><li>Helps coordinate the division of cells </li></ul></ul><ul><li>Surrounded by a Nuclear Envelope </li></ul><ul><li>Envelope is double layered with an Inner & Outer membrane </li></ul><ul><ul><li>Has perforations called Nuclear Pores which allow large molecules to pass in/out of the nucleus </li></ul></ul><ul><li>Contains a Nucleolus </li></ul><ul><ul><li>Ribosomes are made in this region </li></ul></ul><ul><li>Contains DNA packaged in structures called chromosomes </li></ul>Chromosomes
  9. 9. Mitochondria <ul><li>Serves as the “powerhouse of the cell” by generating chemical energy </li></ul><ul><ul><li>Has it’s own DNA* </li></ul></ul><ul><ul><li>Can divide on its own* </li></ul></ul>
  10. 10. Chloroplasts (Plant Cell Only) <ul><li>Is the “cell’s farm” - meaning food is generated here. </li></ul><ul><li>Does this by photosynthesis - the conversion of CO 2 , H 2 O and sunlight into sugar </li></ul><ul><li>Contain Chlorophyll - a green pigment - which does this </li></ul><ul><li>Has it’s own DNA* </li></ul><ul><li>Can divide on its own* </li></ul>
  11. 11. Ribosomes <ul><li>Are NOT membrane-bound & also exist in prokaryotes </li></ul><ul><li>Are used to manufacture proteins </li></ul><ul><li>Granular in appearance </li></ul><ul><li>Often found on “rough” endoplasmic reticulum * </li></ul>
  12. 12. Endoplasmic Reticulum <ul><li>Are folds of membranes used to package & modify proteins made by ribosomes. They also make lipids </li></ul><ul><li>2 types </li></ul><ul><ul><li>“ Rough ” - which is usually near nucleus and covered with ribosomes giving it its “rough” appearance. (Finishes proteins) </li></ul></ul><ul><ul><li>“ Smooth ” - which is usually away from the nucleus (produce lipids) </li></ul></ul>
  13. 13. Examples of Endoplasmic Reticulum Smooth ER Rough ER
  14. 14. Golgi Bodies <ul><li>Are the post offices of the cell </li></ul><ul><li>Modify (address) proteins & lipids and send them in packages ( vessicles ) throughout (or out of) the cell. </li></ul>
  15. 15. Lysosomes <ul><li>Small Vessicles which serve to digest particles and clean-up cells </li></ul><ul><li>Contain Lysozyme – a powerful digestive enzyme </li></ul><ul><li>Digests food particles </li></ul><ul><li>Destroys worn-out organelles </li></ul><ul><li>Self-Destructs worn-out cells </li></ul>
  16. 16. Centrioles (Animal Cell Only) <ul><li>Serve as construction/organization points for cellular microtubules </li></ul><ul><li>Organize and transfer chromosomes and other organelles during Meiosis & Mitosis </li></ul><ul><li>Occur in some prokaryotes, protists & animals. Do not occur with fungi and plants </li></ul><ul><li>Tube like structures usually at right angles to each other. </li></ul><ul><li>Some animals have centriole-like structures at the base of flagella called basal bodies . </li></ul>
  17. 17. Tonoplast (water vacuole) (plant cells only) <ul><li>Large H 2 O / Lipid / waste storage tank </li></ul><ul><li>Provides pressure ( Turgor pressure ) to maintain cell structure </li></ul>
  18. 18. Cell Wall <ul><li>Provides support / protection for plant cell </li></ul><ul><li>Two layers of cell wall </li></ul><ul><ul><li>Primary Cell Wall – Outer – Cellulose only </li></ul></ul><ul><ul><li>Secondary Cell Wall – Inner – Cellulose & Lignin </li></ul></ul><ul><li>Cell membrane is innermost layer </li></ul>
  19. 19. Cytoskeleton <ul><li>Network of fibers which help organize the internal arrangement within cells. </li></ul><ul><li>Three basic types of fibers compose cytoskeleton: </li></ul><ul><ul><li>Actin Filaments </li></ul></ul><ul><ul><ul><li>Thinnest fibers ~7nM </li></ul></ul></ul><ul><ul><ul><li>Formed from protein Actin </li></ul></ul></ul><ul><ul><li>Microtubules </li></ul></ul><ul><ul><ul><li>Largest component of cytoskeleton ~25 nM </li></ul></ul></ul><ul><ul><ul><li>Formed from protein Tubulin </li></ul></ul></ul><ul><ul><li>Intermediate filaments </li></ul></ul><ul><ul><ul><li>Intermediate in size and can vary </li></ul></ul></ul><ul><ul><ul><li>Form from several proteins inluding vimentin & keratin </li></ul></ul></ul>