Transcript Cellular Respiration PPT

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
mitochondria.
 Foods are broken down into small molecules
like glucose.
 Glucose is broken down during glycolysis.
Glycolysis

Glycolysis
 Takes place BEFORE cell
respiration.
 Splits the glucose molecule
into two three-carbon
molecules and makes two
molecules of ATP.
 It takes place in the
cytoplasm of the cell.
 It is an anaerobic process.
○ Does NOT require oxygen
to take place.
Glycolysis
1. Two ATP molecules are used to
energize a glucose molecule.
– The glucose is then split into two
three-carbon molecules.
2. Energized electrons from the
three-carbon molecules are
transferred to molecules of NAD+.
– This makes NADH. (this is an
enzyme that helps energy
production)
– A series of reactions convert the
three-carbon molecules into
pyruvate. (used in cellular
respiration)
– 4 ATP molecules are made.
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 down.
 Pyruvate is split into a two-
carbon molecule and
carbon dioxide (given off as
waste).
 The two-carbon molecule
donates high energy
electrons to NAD+, forming
a molecule of NADH.
○ This will move to the
electron transport chain.
2. Coenzyme A
 Bonds to the two-carbon
molecule made by the
breakdown of pyruvate.
Krebs Cycle
3. Citric acid formed.
– The two-carbon molecule
binds to a four-carbon
molecule to form citric acid.
– Coenzyme A returns to step 2.
4. Citric acid broken down.
– The citric acid molecule is
broken down by an enzyme,
and a five-carbon molecule is
formed.
– A molecule of NADH is made
and moves out of the Krebs
cycle.
– A molecule of carbon dioxide
is given off as waste.
Krebs Cycle
•
5. Five-carbon molecule
broken down.
– A four-carbon molecule, a
molecule of NADH, and a
molecule of ATP are formed.
– NADH leaves the Krebs Cycle.
– Carbon dioxide is given off as
waste.
•
6. Four-carbon molecule
rearranged.
– Enzymes rearrange the four-
carbon molecule, releasing
high-energy electrons.
– NADH and FADH2 (another
enzyme/electron carrier) are
made.
– They leave the Krebs cycle and
the four-carbon molecule
remains.
Krebs Cycle Products
•
•
The Krebs cycle will break down
TWO pyruvate molecules at the
same time.
Products:
– 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
electrons.
Electron Transport Chain
•
3. ATP produced.
– The hydrogen pumps through a protein
channel in the mitochondrial membrane
with ATP synthase.
– ATP synthase adds phosphate groups to
ADP to make ATP molecules.
• Each pair of electrons (hydrogen) that
passes through results in an average of 3
ATP molecules made.
•
4. Water formed.
– Oxygen enters the cycle and picks up
extraneous hydrogen, forming water.
• This is given off as a waste.
Electron Transport Chain
Electron Transport Chain
Products

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
– 36-34 ATP from cellular respiration (Krebs
Cycle and Electron Transport Chain)
•
•
Other products include carbon dioxide
and water.
The equation for cellular respiration is:
– C6H12O6 + 6O2
6CO2 + 6H2O
Fermentation
•
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
Animals
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
Plants
1. Pyruvate and NADH from
glycolysis enter alcoholic
fermentation.
 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
Photosynthesis



Cellular Respiration and
Photosynthesis are approximately
the reverse of each other.
Photosynthesis stores energy.
Cellular Respiration releases it.
Photosynthesis
Cellular Respiration
Organelle for
Process
Reactants
Chloroplast
Mitochondria
CO2 and H2O
Electron Transport
Chain
Proteins within
thylakoid membrane
Cycle of Chemical
Reactions
Calvin cycle in stroma
of chloroplasts builds
sugar molecules.
Products
Sugars (C6H12O6) and
O2
Sugars (C6H12O6) and
O2
Proteins within inner
mitochondrial
membrane
Krebs cycle in matrix
of mitochondria
breaks down carbonbased molecules.
CO2 and H2O