MITOCHONDRIA STRUCTURE

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MITOCHONDRIA STRUCTURE

• By
• Prof. DR. IR. CHANIF MAHDI, MS.
• DEPARTEMENT OF CHEMISTRY
• BRAWIJAYA UNIVERSITY

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Diagrame of the mitochondria structure
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Mitochondria

• Mitochondria contain two membranes, separated by
  space. Inside the space enclosed by inner
  membrane is the matrix.
• These appears moderatly dense and one may find
  strands of DNA, Ribosome, or small granula in the
  matrix.
• The above diagrame shows the diagram of the
  mitochondrial membranes and the enclosed
  compartement.

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Contd

• Mitochondria is the Power of house of the cell.
• How are mitochondria organized to be power
  house.
• The food we eat is oxidized to produce high
  energy electrons that converted to store energy.
  This energy is stored in high energy phosphat
  bond in a molecule called Adenosine Triphosphate
  (ATP).
• ATP is converted from Adenosine Diphosphat by
  adding the phophat group with high energy bond.
• Various reaction in the cells can be either use
  energy ( where by the ATP is converted back to
  ADP( releasing the high energy bond).

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REAKSI PEMBENTUKAN ENERGI

• C6 (H2O)6 H2O O2 4H 4 e
• NADP 2 H 2 e NADPH H
  Energi
• Energi ADP H3 PO4 ATP

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Why are mitochondria important

• The food we eat must first be converted to basic
  chemicals that the cell can use. Some of the best
  energy supplaying foods contain sugar or
  carbohydrates.
• The sugars are broken down by enzymes that split
  them into into simplest form sugar which called
  glucose . Then glucose enters the cell by special
  molecules in the membrane called Glucose
  transporter.

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Contd

• Once inside the cell, glucose is broken down to
  make ATP in two pathways.
• The first pathways requires no oxygen and is
  called anaerobic metabolism this pathway is
  called glycolysis and it occur in the cytoplasm,
  outside of mitochondria.
• During glycolysis, glucose is broken down into
  pyruvate.

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Contd

• Each reaction is designed to produce some
  hydogen ions (electron) that can be used to make
  energy packet ( ATP ). However, only 4 ATP
  molecules can be made by one molecule of glucose
  run through this pathway.
• That is why mitochondria and oxygen are so
  important.We need to continou the breakdown with
  the Krebs cycle inside the mitochondria in orde
  to enough ATP to run all the cell function.

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Figure 2. Mitochondria as power house of the cell
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Figure Glycolysis diagrame
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Figure Anaerob and aerob meabolism
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Figure 2. Information

• Pyruvat is carried into the mitochondria and it
  converted into Acetyl Coa which enter the Krebs
  cycle. This first reaction produce carbon
  dioxide, because it involves the removal of one
  carbon from pyruv, atc.
• How does the Krebs Cycles work.
• The whole idea behind respiration in the
  mitochondria is to use the Krebs ( also called
  the Citric acid Cycle ) to get many electron ( in
  the form of hydrogen ions ), are then used to
  drive pumps that produce ATP. The energy carried
  by ATP is than used for all kind of cellular
  function, like movement, transport, entry and
  exit products, devision, etc.

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Contd

• First, you need pyruvate, which is made by
  glycolysis from glucose. Next you need some
  carrier molecule for the electrons. There are two
  types of these one called Nicotinamide Adenin
  Dinucleotide ( NAD ), and the other is called
  Flavin Adenin Dinucleotid ( FAD ), The third
  molecule, of course is oxygen.
• Pyruvat is a 3 carbon molecule. After inter the
  mitochondria, it is broken down to a 2 carbon
  molecule by special enzyme. This release

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contd

• molecule are called acetyl Coa and it enters the
  Krebs Cycle by joining to 4 carbon molecule
  called Citric acid ( 2 carbon 4 carbon 6
  carbon). That is where the citric acid cycle got
  it name. ( from the first reaction, that make
  citric acid).
• Citric acid is then broken down, and modified in
  a stepwise fashion ( See text for details), and
  as the happens, hidrogen ions and carbon
  molecules are released.
• The carbon molecules are used to make more
  carbon dioxide and the hydrogen ions are picked
  up by NAD and FAD.

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Contd

• Eventually the process produces the 4 carbon
  oxalo acetat again. The reason, the process
  called cycle, is because its ends up always where
  it started, with oxalo acetat available to
  combine with more acetyl Coa.

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Oxydative Phosphorilation

• First some basic difinition. When you take
  hydrogen ion or electron away from molecule, you
  oxydaze that molecule. When you give hydrogen
  ion or electron to a molecule, you reduce that
  molecule.
• So, oxidative phosphorilation ( very simply)
  mean, the process that couples the removal of
  hydrogen ion from molecule and giving phosphat
  molecule to another molecule. How does this apply
  to mitochondria?

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Contd

• As the Krebs cycle runs, hydrogen ion ( or
  electron ), are donated to the two carrier
  molecules in the 4 of the steps. They are picked
  up by either NAD or FAD, and this molecules
  became NADH and FADH ( becauce they now are
  carrying a hydrogen ion). The following diagrame
  shows what heppens next ( Figure 3).

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Figure 3.
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More information Figure 3

• The electron are carried chemically to the
  respiratory or electron transport chain found in
  the mitochondria crestae ( see diagram above and
  bellow).
• The NADH and FADH essentially serve as Ferry in
  the lateral plane of the membrane diffusing from
  one complex to the next.
• At each site is the hydrogen (or proton) pump
  which transfers hydrogen from one side of the
  membrane the other. This creates a gradient a
  cross the inner membrane with a higher
  concentration of hydrogen ion in the intercrestae
  space ( The space between inner and outer
  membranes). ( Figure 4). The diagram shows the
  individual complexes in electron transport chain.

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• The following diagram shows the individual
  complex in the electron transport chain. The
  elecron are carried from complex to complex by
  ubiquinon and cytochrome C.
• In the third pump in the series catalyzes the
  transfer of electron to oxygen to make water.
  This semiosmotic pumping creates.
• An electrochemical proton gradient a cross the
  membrane which is used to drive the Energy
  Producing Machine. The ATP Synthase this
  molecule is found in small elementary particle
  that project from crestae. See figure 5 ).

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Figure 4.
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More information figure 5

• As started above, this process requires oxygen,
  which is called aerobic metabolism The ATP
  Synthase uses energy of the hydrogen ion ( also
  called proton) gradient to form ATP from ADP and
  Phosphat. It also produces water from hydrogen
  and oxygen. Thus, each compartement of the
  mitochondria is specialized for one phase of this
  reaction.
• How oxidation is coupled to phophorilation
• To Review
• NAD and FAD remove the electron that are donated
  during some of the steps of the Krebs or citric
  acid cycle.

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Figure 5
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Contd

• They carried the electron to one electron
  transport Pump and donate them to the pump. So
  NAD and FAD are Oxidized because they loss the
  hydrogen ion to the pump. The pump then transport
  the hidrogens ion to space between two membranes,
  where they accumalate in high enough
  concentration fuel to the ATP pumps. With
  sufficient fuel, they Phosphorylate the ADP
  That is how oxidation is coupled to
  phosphorilation.
• The hydrogen that get pumped back into the
  matrix by ATP pump than combine with oxygen to
  make water. And that is very important because,
  without oxygen, they will accumulate and the
  concentration gradient needed to turn the ATP
  pump will not allow the pump work.

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So, Why do we need mitochondria

• The whole idea behind process to get as much ATP
  out of glucose (or other food product) as
  posible. If we have no oxygen, we get only 4
  molecule ATP s for energy packet each glucose
  molecule (in glycolysis).
• However, if we have oxygen, then we get to run
  Krebs cycles to product many more hydrogen ion,
  can run those ATP pumps, from the Krebs cycle we
  get 24- 28 ATP molecules out of one molecule of
  glucose converted to pyruvate.
• So you can see how much more energy we can get
  out of a molecule of glucose, if mitochondria are
  working, and if we have oxygen.

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Importance of the crestae

• Not only do they contain and organize the
  electron transport chain and the ATP pump, they
  also servte to separate the matrix from the space
  that will contain the hydogen ion, allowing the
  gradient needed to drive the pump.
• As shown in the above diagam, the molecules in
  the electron transport chain are found as cluster
  organized in the crestae. These membrane sheves
  maybe more numerous in mitochondria that are
  active in production ATP ( Gambar 6 ).

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More information of figure 6

• Mitochondria can be separated and the inner and
  outer membrane can be dissociated. This will
  result in a fraction containing only the inner
  membrane and matrix. These have been called
  Mitoplast. They are functional and have helped
  us learn more about the compartementation of
  mitochondria.

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Figure 6 Cyochrome C lying just outside the
inner membrane
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Figure 7 Cytochrome is on the inner membrane