Download Chapter 6

Aerobic and anaerobic cell respiration
 What
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
does respiration mean?
can mean breathing or ventilation of lungs or
gills
Can refer to gas exchange in the blood at the
cellular level (oxygen in/carbon dioxide out)
Can refer to the complex set of reactions that
allow cells to burn sugar to make ATP
 What
systems of the body are responsible for
carrying these reactions out?
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Respiratory (oxygen/carbon dioxide exchange)
Cardiovascular (transport)
Digestive (digestion and absorption of glucose)
We can “burn” molecules other than glucose
There are MANY steps in this process. Balanced
equation is simplified
 Three
general reactions- aerobic cell
respiration
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Glycolysis – happens in cell cytoplasm
Kreb’s Cycle – happens in matrix of mitochondria
Oxidative Phosphorylation/ETC- occurs in
proteins in inner mitochondrial membrane called
the Electron Transport Chain
 Splitting
of sugar
 Glucose split into two three carbon
molecules called pyruvate and energy is
released.
 Energy is used to make 2 ATP by substrate
Level Phosphorylation- ATP made without
ETC
 Energy is also used to make 2 NADH-an
energy storage molecule to be “cashed out”
later
 No oxygen needed in this step!
 Each
pyruvate is broken down into 3 CO2
molecules
 Energy stored in
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4 NADH
1 FADH2 (also a “check” to be cashed out)
1 ATP ( made by SLP- no ETC)
Is a cycle – begins and ends with same molecule
How many times must the cycle run/glucose?
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 Cycle
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turns twice for each glucose
8 NADH
2 FADH2
2ATP
6CO2
PHASE
ATP
NADH
FADH2
GLYCOLYSIS
2 by SLP
2
0
KREB’S CYCLE
2X per glucose
2 by SLP
8
2
ETC
?????
0
0
 Energy
rich electrons stored in NADH and
FADH2 are cashed in at a cascade of proteins
in the inner mitochondria membrane
 As electrons fall they lose energy- exergonic
 Energy released is COUPLED with the active
transport of H+ ions across the membrane
 Called chemiosmosis
 Oxygen
accepts the electron at the end of
the chain- H+ combine with oxygen and the
electron to make water (waste)
 H+ accumulate in intermembrane space
 Rush back to matrix through ATP synthase(light bulb shaped protein) release lots of
energy
 Energy is used to add a phosphate to ADP to
make ATP !!!
 This is called oxidative phosphorylation
 Phosphorylation-
to make ATP
 Oxidative – using oxygen as last electron
acceptor (ETC)
 Substrate level- without ETC, using enzymes
in the mitochondria and cytoplasm
Phase
ATP
NADH
FADH2
Glycolysis
2
2 (worth 2 ATP
each)
0
KREB’S
2
8 (worth 3 ATP
each)
2 (worth 2 ATP
each)
ETC cash out
value
N/A
4 ATP + 24 ATP= 4 ATP
28 ATP
TOTAL ATP =
36 / glucose
2
from glycolysis are only worth 2 ATPs.
 They have to travel through two
mitochondrial membranes
8
NADHs from Kreb’s are already in
mitochondria – are worth 3 ATPs each
 Prokaryotes
make 38 ATPs – no internal
membranes to pass through