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Eukaryotic Cell Structure Chapter 7 Eukaryotic Cell Structure Chapter 7 2

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Eukaryotic Cell Structure Chapter 7 Eukaryotic Cell Structure Chapter 7 2 Powered By Docstoc
					Eukaryotic Cell
  Structure
    Chapter 7.2
         The Eukaryotic Cell
• Divided into two major parts:

  1. The nucleus

  2. The cytoplasm
      Portion of the cell outside the nucleus
      Contains the organelles
              Organelles
• Functional components of the cell
   Each carries out a specific job
   Determines the job of the cell
   Work together to make the cell function

• Typically surrounded by a membrane
   – Same membrane structure that surrounds
     the cell
   – Allows incorporation between organelles
     and the cell membrane
    How these notes work

      • Red = Cell structure
        • Green = Function
  • Purple = Other information
• Picture = Structure (separate
               slide)
                The Nucleus
• The nucleus holds nearly all of the cell’s DNA
  and with it the coded instructions for making
  proteins and other important molecules
  • control center of the cell
  – Surrounded by a double membrane with pores in it
    nuclear envelope outer boundary of the nucleus


• Houses genetic material and nucleolus
  – Genetic material = DNA and proteins
  – Nucleolus  makes ribosomes
The Nucleus
          Genetic Material
• Chromatin
  – Tangles mass of protein and DNA


• Chromosome
  – Highly organized and compact mass of
    protein and DNA


Chromatin becomes a chromosome
 before cell division
Chromatin
            Chromosome
             Ribosomes
 Site of protein synthesis

 Composed of RNA and protein

 Can be attached or free-floating

Most common organelle
 - found in prokaryotes as well
    Endoplasmic Reticulum (ER)
• The site where lipid components of the cell
  membrane are assembled; along with proteins and
  other materials that re exported from the cell

• Two types

  – Smooth ER – no ribosomes attached to it
     Contains collections of enzymes that perform specialized
      tasks (makes membrane lipids and detoxifies drugs)

  – Rough ER – has ribosomes attached to it
     Portion of ER where protein synthesis occurs
        – Newly made proteins enter the ER and are modified
          Golgi Apparatus
• The function of the Golgi Apparatus is to
  modify, sort, and package proteins and
  other materials from the ER for storage
  in the cell or secretion outside the cell
                Lysosomes
 Small organelles filled with digestive
 enzymes

  – Digestion of macromolecules into small
    molecules that can be used by the rest of the cell


  – Breakdown of organelles that have outlived their
    usefulness


  – Cell suicide organelles
Lysosomes
                 Vacuoles
 Store materials such as water, salts,
 proteins, or carbohydrates

  – One large vacuole is found in plant cells
    • Allows the plant to grow tall


  – Found in some single celled organisms
    and in some animals
    • Used to control the amount of water in the
      organism
       – Homeostatic mechanism
              Mitochondria
 Convert the chemical energy stored in
 food into compounds that are more
 convenient for the cell to use
  – Enclosed by two membranes
    • Inner membrane is highly folded
       – Called cristae



• FYI = All mitochondria come from your
  mother
               Chloroplast
 Capture the energy from sunlight and
 convert it into chemical energy in a
 process called photosynthesis

• Mostly found in plants (some other
  single celled organisms)
  – Surrounded by two membranes
    • Highly stacked internal membrane
      – Called the thylakoid
      – Holds chlorophyll
  Mitochondria and Chloroplast
• Both contain their own DNA

• Endosymbiotic theory
  – Lynn Margolis suggested that ancient
    mitochondria and chloroplasts were
    independent prokaryotes
    • Created a symbiotic relationship with early
      eukaryotes
            Cytoskeleton
 Network of protein filaments that help
 the cell to maintain its shape
  – Also involved in movement


• Principle protein filaments
  – Microfilaments
  – Microtubules
    Centrioles / Cilia / Flagella
• Centrioles, cilia, and flagella are all made
  of microtubules

• Centrioles
   Help to organize cell division
     • Only in animal cells


• Cilia / Flagella
  Hair-like projections that enable cells to
   “swim” in a liquid environment

				
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posted:3/17/2012
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