CHAPTER 6 - CELLS

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CHAPTER 6 - CELLS

• Section 6.1 6.2

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Importance of cells

• An organisms basic unit of structure function
  is the cell
• Everything we do occurs fundamentally at the
  cellular level
• Thinking
• Moving
• Maintaining homeostasis
• Cells discovered by Robert Hooke in 1665

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Studying Cells

• How do we understand cells if we cant see them?
• Microscopes allow us to see the inner workings of
  cells
• Two main types of Microscopes
• Light Microscope (LM) 1665-present
• Electron Microscope (EM) 1950s-present

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Light Microscopes

• Allow us to see plant animal cells and the
  nucleus.
• Can also see bacteria cells.
• Light passes through the specimen and lenses,
  bends the light to magnify the image.
• Magnification ratio of an objects image to its
  real size (max. about 1,000x)
• Resolution measure of the clarity of the image
  (max. about 200nm size of bacteria)

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Electron Microscopes

• Rapidly advance our understanding of cells
  because we could see subcellular structures
• Focuses a beam of electrons through the specimen
• Two types
• Scanning electron microscope (SEM)
• Gives a 3D image of the surface of the specimen
• Transmission electron microscope (TEM)
• Used to study internal stux gives a cross
  section

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Advantages Disadvantages

• Light Microscopes
• Advantage Can study living organisms
• Disadvantage Cant see organelles in detail
• Electron Microscopes
• Advantage Can see organelles in detail
• Disadvantage Specimens are killed in preparation
  process (not for living tissues)

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Cell Fractionation

• Goal take cells apart and separate the major
  organelles from one another
• Process
• Centrifuge spins test tubes at various speeds
• Cell components separate by size and density
• Result
• Bulk quantity of cellular organelles to study
  composition and function

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Section 6.2

• Two types of cells
• Prokaryotic found in Domain _______ _______
• Eukaryotic found in Domain _______
• What 4 Kingdoms contain organisms with Eukaryotic
  cells?
• 1. Animal
• 2. Plant
• 3. Protist
• 4. Fungi

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Similarities Differences

• All Cells contain
• Plasma membrane made up of a __________
• Phospholipid bilayer
• Cytosol (cytoplasm)
• DNA
• Ribosomes
• Differences
• Eukaryotic cells contain membrane bound
  organelles and the DNA is contained in the
  nucleus.

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Prokaryotic cells

• DNA located in nucleoid region
• Prefix pro means before
• Suffix karyon means kernel (nucleus)
• No membrane bound organelles in cytoplasm
• Smaller simpler
• Cilia and flagella for locomotion
• Some have cell wall surrounding plasma membrane

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Prokaryotic cells
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Cell Size

• Cellular metabolism sets a limit on how large a
  cell can get
• The cell needs to bring in oxygen nutrients and
  needs to get rid of waste
• Cell needs to maintain a high surface area to
  volume ratio to exchange the materials it needs
  to
• Larger organisms do not have larger cells just
  more of them (we have trillions of cells!)

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Surface area to volume ratio
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Plasma membrane
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Eukaryotic cells

• Contain membrane bound organelles
• Larger than prokaryotic cells and more complex
• Animal Plant cells
• Draw a diagram of an animal and a plant cell

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