Download Cellular Respiration

“Let’s Take a Breather”.
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C6H12O6 + 6O2 -----> 6CO2 + 6H20 +
energy (heat and ATP)
Energy
Capacity to move or change matter
Forms of energy are important to life include
Chemical, radiant (heat & light), mechanical,
and electrical
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Energy can be transformed from one form to
another
Chemical energy is the energy contained in
the chemical bonds of molecules
Radiant energy travels in waves and is
sometimes called electromagnetic energy. An
example is visible light
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Photosynthesis converts light energy to
chemical energy
Energy that is stored is called potential
energy
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Energy carrying molecule used by cells to fuel
their cellular processes
ATP is composed of an adenine base, ribose
sugar, & 3 phosphate (PO4) groups
The PO4 bonds are high-energy bonds that
require energy to be made & release energy
when broken
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ATP is made & used continuously by cells
Every minute all of an organism's ATP is
recycled
Phosphorylation refers to the chemical
reactions that make ATP by adding Pi to ADP
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C6H12O6 + 6O2 -----> 6CO2 + 6H20 +
energy (heat and ATP)
Controlled release of energy from organic
molecules (most often glucose)
Glucose is oxidized (loses e-) & oxygen is
reduced (gains e-)
The carbon atoms of glucose (C6H12O6) are
released as CO2
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Generates ATP (adenosine triphosphate)
The energy in one glucose molecule may be
used to produce 36 ATP
Involves a series of 3 reactions --Glycolysis, Kreb's Cycle, & Electron Transport
Chain
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Occurs in the cytoplasm
Summary of the steps of Glycolysis:
a. 2 ATP added to glucose (6C) to energize it.
b. Although glycolysis makes 4 ATP, the net
ATP production by this step is 2 ATP (because
2 ATP were used to start glycolysis). The 2
net ATP are available for cell use.
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c. If oxygen is available to the cell, the
pyruvate will move into the mitochondria &
aerobic respiration will begin.
Net Yield from Glycolysis
4 NADH2
2 CO2
4 ATP ( 2 used to start reaction)
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d. If no oxygen is available to the cell
(anaerobic), the pyruvate will be fermented by
addition of 2 H from the NADH (to alcohol +
CO2 in yeast or lactic acid in muscle cells).
This changes NADH back to NAD+ so it is
available for step c above. This keeps
glycolysis going!
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A. Alcoholic Fermentation—Alcohol (Wine,
Beer)
B. Lactic Acid Ferm.
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Occurs in the mitochondria
Includes the Krebs Cycle & the Electron
Transport Chain (ETC)
CO2 and NADH are also produced
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Named for biochemist Hans Krebs
Metabolic pathway that indirectly requires O2
Kreb's Cycle is also known as the Citric acid
Cycle
Requires 2 cycles to metabolize glucose
CO2 is a waste product that diffuses out of
cells
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6
2
4
2
NADH2
FADH2
CO2
ATP
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Found in the inner mitochondrial membrane
Contains 4 protein-based complexes that
work in sequence moving H+ from the matrix
across the inner membrane (proton pumps)
Energized e- & H+ from the 10 NADH2 and 2
FADH2 (produced during glycolysis & Krebs
cycle) are transferred to O2 to produce H2O
(redox reaction)
O2 + 4e- + 4H+ 2H2O
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At the end of the electron transport chain, the electrons
combine with H+ ions and oxygen to form water.
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Glycolysis
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4 NADH2
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0 FADH2
2 ATP
Kreb's Cycle
6 NADH2
2 FADH2
2 ATP
Total
10 NADH2 x 3 = 30 ATP
2 FADH2 x 2 = 4 ATP
4 ATP
Total: 38 ATP
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Most cells produce 36- 38 molecules of ATP
per glucose (66% efficient)
Actual number of ATP's produced by aerobic
respiration varies among cells