MITOCHONDRIA AND CHLOROPLASTS

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MITOCHONDRIA AND CHLOROPLASTS

• Structure and function - a review

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The Exam Question

• Contrast and compare mitochondria and
  chloroplasts structure and function.
• Do you know what it means?
• What is the function of a mitochondrion?
• What is the function of a chloroplast?
• How are they similar? How are they different?

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Energy Conversion

• Mitochondria convert the chemical energy of
  reduced carbon compounds into ATP.
• Chloroplasts convert light energy to the energy
  of reduced carbon compounds
• Fundamental to both processes is an electron
  transport chain, where energy is passed from
  compound to compound in coupled
  oxidationreduction reactions

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Mitochondria

• 2 membranes
• Outer Membrane - has large aqueous channels made
  of a protein called porin - permeable to most
  small molecules
• Inner Membrane - impermeable to ions and small
  molecules except by specific membrane-transport
  proteins

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Mitochondria

• 2 compartments
• MATRIX - enzymes -TCA cycle, DNA - several
  copies, ribosomes, tRNA, etc
• INTERMEMBRANE SPACE
• Inner Membrane is folded into cristae,that
  greatly increase its surface area. This is where
  you find the Electron Transport Chain (ETC), ATP
  synthase, transport proteins to allow substances
  in to matrix

Fig 1-11
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Mitochondrial Structure

• How many compartments do mitochondria have?
• Which letter corresponds to
• the matrix?
• a crista?
• the intermembrane space?
• the outer membrane?
• the inner membrane?
• Where would you find the DNA? the ribosomes?

A
C
E
D
B
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ELECTRON TRANSPORT CHAIN

• The ETC is found on the inner membrane
• High energy electrons are passed along the ETC
  generating a proton gradient across the inner
  membrane
• H gradient drives ATP synthesis

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Mitochondria have 2 membranesChloroplasts have 3
membranes
There are 3 compartmentswhat are they?
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Chloroplast

• Thylakoid membrane proteins of ETC, ATP
  synthase
• Inner membrane membrane transport protein for
  Rubisco
• Outer membrane - porin
• Stroma enzymes for Calvin Cycle, chloroplast
  DNA.

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Chloroplasts
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Plant Cell
Fig 13-26
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Chloroplasts vs Mitochondria
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These are mitochondria
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So are these
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Chloroplasts have different forms too
Thylakoids
Mitochondria
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But their structure and function remain linked

• Think of 3 similarities between mitochondria and
  chloroplasts.
• Think of 3 ways they are different

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• Vesicle Trafficking
• Models of Golgi function
• Receptor-mediated endocytosis
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