Cellular Respiration

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Transcript Cellular Respiration

Cellular Respiration
Cellular respiration releases chemical
energy from sugars and other carbonbased molecules to make ATP.
 It is an aerobic process.
 needs oxygen to take place.
Cellular Respiration
Cell respiration takes place in the
 Foods are broken down into small molecules
like glucose.
 Glucose is broken down during glycolysis.
 Takes place BEFORE cell
 Splits the glucose molecule
into two three-carbon
molecules (pyruvates) and
makes two molecules of
 It takes place in the
cytoplasm of the cell.
 It is an anaerobic process.
○ Does NOT require oxygen
Krebs Cycle
The first part of cellular respiration.
 Sometimes called the citric-acid cycle.
Produces molecules that carry energy to
the second part of cellular respiration.
(NADH and FADH2)
 Takes place in the interior space (matrix)
of the mitochondria.
Krebs Cycle
1. Pyruvate broken
 Pyruvate is split into 3
molecules of carbon
Dioxide which are given
off as waste
• 4 molecules of NADH
and one FADH2 form.
• They will move to the
electron transport
Krebs Cycle Products
The Krebs cycle will break down
TWO pyruvate molecules at the
same time.
– 6 carbon dioxide molecules.
– 2 molecules of ATP
– 8 molecules of NADH
• Will go to the electron transport chain.
– 2 molecules of FADH2
• Will go to the electron transport chain.
Electron Transport Chain
Second part of cellular respiration.
 Energy from the Krebs cycle (NADH and FADH2)
is transferred to a chain of proteins in the inner
membrane of the mitochondrion.
 A large number of ATP molecules are made.
 Oxygen is used to make water molecules.
 Water and heat are given off as a waste
Electron Transport Chain
1. Electrons removed.
 Proteins inside the mitochondrion take high-
energy electrons from NADH and FADH2.
○ Two molecules of NADH and one of FADH2 are used.
2. Hydrogen ions transported.
 Hydrogen ions are built up along the inner
mitochondrial membrane using energy from the
Electron Transport Chain
Electron Transport Chain
For EACH molecule of glucose the ETC
can make:
 Up to 34 molecules of ATP
Cellular Respiration Products
Up to 38 ATP are made from the
breakdown of ONE glucose molecule.
– 2 ATP from glycolysis
– 36 ATP from cellular respiration (Krebs - 2)
Cycle and Electron Transport Chain - 34)
Other products include carbon dioxide
and water.
The equation for cellular respiration is:
– C6H12O6 + 6O2
6CO2 + 6H2O
Fermentation is an anaerobic process
that takes place when there is less
oxygen in the body (i.e. during
strenuous activity)
• Fermentation does NOT make ATP, but
it allows glycolysis to continue.
– Glycolysis needs NAD+ to pick up electrons
when it splits glucose into pyruvate.
– Fermentation removed electrons from
NADH molecules and recycles NAD+
molecules for glycolysis.
Lactic Acid Fermentation in
1. Pyruvate and NADH from
glycolysis enter fermentation.
 Two NADH molecules are used to
convert pyruvate into lactic acid.
○ As the NADH is used, it converts
back to NAD+.
2. TWO molecules of NAD+ are
recycled back to glycolysis.
 This allows your body to continue to
break down sugar for energy!
Alcoholic Fermentation in
1. Pyruvate and NADH from
glycolysis enter alcoholic
 The NADH molecules provide energy
to break pyruvate into alcohol and
carbon dioxide.
○ As the NADH are used, they are
converted to NAD+.
2. The molecules of NAD+ are
recycled back to glycolysis.
 The recycling of NAD+ allows
glycolysis to continue.
Cellular Respiration and
Cellular Respiration and
Photosynthesis are approximately
the reverse of each other.
Photosynthesis stores energy.
Cellular Respiration releases it.
Photosynthesis and Cellular
Cellular Respiration
Organelle for
CO2 and H2O
Electron Transport
Proteins within
thylakoid membrane
Cycle of Chemical
Calvin cycle in stroma
of chloroplasts builds
sugar molecules.
Sugars (C6H12O6) and
Sugars (C6H12O6) and
Proteins within inner
Krebs cycle in matrix
of mitochondria
breaks down carbonbased molecules.
CO2 and H2O