The Cell

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The Cell

• All Living things are composed of cells
• All Cells have/contain the following
• Cell Membrane - Lipid Bilayer - Separates inside
  from outside

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Cytoplasm

• Cytoplasm - everything but DNA/Nucleus

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Two Cell types

•         Prokaryotic Cells
• 1.      Primitive cells include bacteria
• 2.     No nucleus
• 3.     No Membrane-bound organelles
• 4.     Very Small 1-10 micrometers
• 5.     Single Strand of Circular naked DNA
• 6.     Contain Ribosomes

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Typical Prokaryotic Cell
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Eukaryotic Cells

• Eukaryotic Cells
• 1.      Contain a Nucleus which protects DNA /
  Chromosomes
• 2.     Much larger than prokaryotic cells
• 3.     Have many different types of Membrane
  bound organelles - compartmentalization
  efficiency

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Eukaryotic Cells
Animal Eukaryotic Cell
Plant Eukaryotic Cell
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Organelles

• Membrane-Bound organelles only found in
  Eukaryotes
• Localize Chemical Reactions making the cell far
  more efficient

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Major Organelles of the Eukaryotic Cell

• The Nucleus
• eukaryotic means true nucleus
• Contains protects the cells DNA
• Helps coordinate the division of cells
• Surrounded by a Nuclear Envelope
• Envelope is double layered with an Inner Outer
  membrane
• Has perforations called Nuclear Pores which allow
  large molecules to pass in/out of the nucleus
• Contains a Nucleolus
• Ribosomes are made in this region
• Contains DNA packaged in structures called
  chromosomes

Chromosomes
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Mitochondria

• Serves as the powerhouse of the cell by
  generating chemical energy
• Has its own DNA
• Can divide on its own

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Chloroplasts (Plant Cell Only)

• Is the cells farm - meaning food is generated
  here.
• Does this by photosynthesis - the conversion of
  CO2, H2O and sunlight into sugar
• Contain Chlorophyll - a green pigment - which
  does this
• Has its own DNA
• Can divide on its own

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Ribosomes

• Are NOT membrane-bound also exist in
  prokaryotes
• Are used to manufacture proteins
• Granular in appearance
• Often found on rough endoplasmic reticulum

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Endoplasmic Reticulum

• Are folds of membranes used to package modify
  proteins made by ribosomes. They also make
  lipids
• 2 types
• Rough - which is usually near nucleus and
  covered with ribosomes giving it its rough
  appearance. (Finishes proteins)
• Smooth - which is usually away from the nucleus
  (produce lipids)

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Examples of Endoplasmic Reticulum
Smooth ER
Rough ER
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Golgi Bodies

• Are the post offices of the cell
• Modify (address) proteins lipids and send them
  in packages (vessicles) throughout (or out of)
  the cell.

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Lysosomes

• Small Vessicles which serve to digest particles
  and clean-up cells
• Contain Lysozyme a powerful digestive enzyme
• Digests food particles
• Destroys worn-out organelles
• Self-Destructs worn-out cells

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Centrioles(Animal Cell Only)

• Serve as construction/organization points for
  cellular microtubules
• Organize and transfer chromosomes and other
  organelles during Meiosis Mitosis
• Occur in some prokaryotes, protists animals.
  Do not occur with fungi and plants
• Tube like structures usually at right angles to
  each other.
• Some animals have centriole-like structures at
  the base of flagella called basal bodies.

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Tonoplast(water vacuole)(plant cells only)

• Large H2O / Lipid / waste storage tank
• Provides pressure (Turgor pressure) to maintain
  cell structure

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Cell Wall

• Provides support / protection for plant cell
• Two layers of cell wall
• Primary Cell Wall Outer Cellulose only
• Secondary Cell Wall Inner Cellulose Lignin
• Cell membrane is innermost layer

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Cytoskeleton

• Network of fibers which help organize the
  internal arrangement within cells.
• Three basic types of fibers compose cytoskeleton
• Actin Filaments
• Thinnest fibers 7nM
• Formed from protein Actin
• Microtubules
• Largest component of cytoskeleton 25 nM
• Formed from protein Tubulin
• Intermediate filaments
• Intermediate in size and can vary
• Form from several proteins inluding vimentin
  keratin