Download Cellular Respiration

CHAPTER 9 SECTION 3
C6H12O6 + 6O2 6 CO2 + 6 H2O
CELLULAR RESPIRATION
 Process by which cell breaks down food molecules to
produce ATP.
 3 stages
 Glycolysis (anaerobic)
 Citric Acid Cycle (aerobic)
 Electron Transport Chain (aerobic)
 **aerobic exercise is with OXYGEN
 *** anaerobic is WITHOUT oxygen.
Glycolysis (breaking glucose)
 Series of chemical reactions in the cytoplasm of a cell
that break down glucose (6 carbons) into 2 molecules
of PYRUVIC ACID. (3 carbons)
 Not very effective because it takes 2 molecules to start
the process and only 4 are produced (Net of 2 ATP )
 Following gycolysis the PYRUVIC ACID molecules
move into the mitochondria, the organelle that
transforms energy for the cell.
Glycolysis cont…
 Outside of mitochondria
•
•
•
•
•
 inside of mitochondria
O<>O
O<>O
O<>O
O<>O
O<>O
 Pyruvic acid moves across the membrane
IN THE PRESENCE OF OXYGEN
 Two more aerobic phases begin.
 CITRIC ACID CYCLE (aka KREB’s
cycle)
 ELECTRON TRANSPORT CHAIN
 Without oxygen things will have to develop a back up
survival plan.
Citric Acid Cycle
 Series of chemical reactions that start and begin with the
same molecule (so it’s a cycle!) Acetyl Co A is the starting
and ending molecule.
 For every turn of the cycle 1 molecule of ATP is produced
and 2 molecules of CO2 per Pyruvic acid molecule. (2 ATP
and 4 CO2 total)
 Following the cycle some excited NADH, FADH, and 3 H
molecules drive excited electrons to an Electron Transport
Chain….
Citric Acid
Cycle
NADH + H+
(Acetyl-CoA)
Citric acid
Oxaloacetic acid
NAD+
NADH + H+
(CO2)
NAD+
NAD+
NADH + H+
ADP +
ATP
FADH2
FAD
Electron Transport Chain
 Occurs in MITOCHONDRIAL membrane this time.
 Excited e- brought over by NADH and FADH2 are
passed from protein to protein.
 Some energy is used to make ATP
 Some is used by an enzyme to pump H+ to the center
of the mitochondria.
 Mitochondria inner membrane is positively charged
with H+ ions while the outer membrane is negatively
charged creating a concentration gradient providing
energy for ATP production (just like photosynthesis)
ETC cont
 Final e- acceptor is OXYGEN. Which reacts with 4 H+
to make H2O. This is why oxygen is so important.
Without oxygen the proteins canNOT pass off the final
e- and everything STOPS.
 ETC produces 32 ATP molecules to the 4 already
produced.
 Aerobic Respiration is very efficient.
 Total ATP production in Cell Respiration is 36.
Electron Transport Chain
Electron carrier
proteins
Electron
pathway
NADH
NAD+
FADH2
FAD
4H+ + O2
+ 4 electrons
H2O
ADP +
H2O
Anaerobic Respiration (without
oxygen)
 Times when your cells are without oxygen for a short
period of time such as heavy exercise, and anaerobic
process begins this is called FERMENTATION.
Fermentation will follow glycolysis to produce small
amounts of ATP.
 2 Types
 Lactic Acid Fermentation (2 ATP produced)
 Alcoholic Fermentation (2 ATP produced)
Lactic Acid Fermentation
 Electron Transport chain backs up because O2 is
missing and carriers can’t release their e-.
 The 2 molecules of PYRUVIC ACID from glycolysis
use NADH to form Lactic Acid this releases the NADH
carrier again so it can be used again in glycolysis
(FADH is stuck in the ETChain).
 Lactic Acid starts to build up in Muscle cells where it is
being produced which causes muscle fatigue.
Eventually it makes its way through the blood back to
the liver where it is converted back into pyruvic acid.
Alcohol Fermentation
 Used by yeast cells and some bacteria to produce CO2
and ethyl alcohol.
 Mini lab p236