Energy conversion: Fermentation

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Energy conversion Fermentation
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Announcements

• No quiz during next week lab. session
• Write an informal summary about today lab.
• I will discus this at the end of the lab.
• -Photosynthesis will be taught in 2 lab. session
• come prepared (as usual) and for the first week
  
• exercise read the protocol at page 5-5 to 5-11
  

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Today

• Terminology
• Respiration
• Fermentation
• High energy bonds
• Terminal electron acceptors
• fermentation exercise
• The Informal summary

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Terminology

• Polar charged
• Non polar uncharged
• Reduced losing O
• acquiring H atom
• acquiring electrons
• -Oxidized acquiring O atom
• losing H atom
• losing electrons
• -Hydrogen ion H proton

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Terminology

• Metabolism sum of total reaction that occur in a
  cell
• and it consist of two
  types of processes
• 1- Catabolismcomplex molecules are broken down
• into simpler molecules
  with the
• release of energy and
  reducing
• power (electrons).
• 2- AnabolismSynthesis of complex molecules
  from
• simpler ones (building
  blocks) to form
• cell structures and
  macromolecules,
• this requires energy and
  often
• reducing power.

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Respiration

• it is defined as oxidation of a source of energy
  by
• removal of electrons and donation to an
  inorganic
• terminal electron acceptor.
• -the terminal electron acceptor is oxygen, so
  it has
• to happen in aerobic conditions.

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Fermentation

• it is defined as an energy yielding process
  whereby
• organic molecules serve as both electron donors
• and electron accepters.
• -it occur when there is no source for oxygen or
  when
• the cell or organism evolved to live in an
  anaerobic
• conditions
• -some anaerobic conditions include deep levels of
  the
• oceans, human and animal intestinal tracts or
• air-proof flask

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Who does what
-bacteria can either live in aerobic environment,
anaerobic environment or both (facultative
anaerobic). -yeast (baker yeast or Saccharomyces
cerevisiae) is a facultative anaerobic
organism. -human and animal cells generate energy
by respiration (human and animal skeletal
muscle cells can generate energy by
fermentation). -plant cells generate energy by
respiration (when oxygen is liberated from
plants)
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Fermentation versus respiration
A-where energy and reducing power are stored
-Energy carrier -These are intermediate "high
energy" carriers that store this energy until
the cell is ready to use it. -Two main types
1- Adenosine TriPhosphate (ATP) carrier of
chemical energy in the form of high energy
phosphate bonds
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Fermentation versus respiration
2-Nicotinamide Adenine Dinucleotide (NAD) is a
carrier of hydrogen and electrons and is
involved in many oxidation-reduction reactions
in the cell NAD2e-H NADH
2eH
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Fermentation versus respiration
B- Do they have a common pathway -glycolysis or
Embden-Meyerhoff-Parnas pathway (EMP) is a
common pathway. -it occur in the cytosol of the
cell 2ADP2Pi
2ATP Glucose-------------------gt2 pyrovate

2NAD4e-2H
2NADH
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Fermentation versus respiration
C- what is the difference -Basically, how the
limited amount of NDA is Regenerated and
whether pyruvate molecules undergo further
catabolism. -in fermentation, the electrons are
passed to pyruvate with the formation of end
products that is the excreted outside the
cell. Yeast cell
also Co2 is released
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Fermentation versus respiration
Human and animal skeletal muscle cell
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Fermentation versus respiration
-in respiration The reaction continues, where the
pyruvate molecules go into the citric acid cycle
or Krebs cycle yielding more ATP, NADH, and
FADH. -this occur in the matrix of mitochondria
in eukaryotes or in the cytosol in
bacteria. -the reduced molecules passes their
electrons to O2 that serve as terminal electron
acceptor. This process is termed electron
transport chain and occur at the level of
mitochondrial membrane in eukaryotes or cell
membrane in bacteria.
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Fermentation versus respiration
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Fermentation versus respiration
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Fermentation versus respiration
-NADH get oxidized and the total process end
with the production of---Co2 H2O. -However, the
electron transport chain result in proton
gradient outside the membrane, this gradient is
used to generate more ATP molecules using the
protonmotive force
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Fermentation versus respiration
So, fermentation generate 2 ATP molecules, while
Respiration generate 36 ATP molecules
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I got the picture
-start reading at the last paragraph of page
29. -Part B, add deionized water up to 100ml
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The informal summary

• it worth 18 points. It is due next week in lab.
• It is distributed as follow
• 1-abstract--- 6 points
• 2-introduction---3 points
• 3-experimental procedures--- 2 point
• 4-results----2 points
• 5-discussion--- 4 points
• 6-references---1
• it is a rehearsal for a formal one.