Transcript Cellular Respiration

Cellular Respiration
C6H12O6 + O2  CO2 + H2O + energy
Glucose + oxygen carbon + water + ATP
dioxide
Glycolysis
• Glucose is converted into 2 pyruvate.
• NAD+ becomes NADH
• Net 2 ATP
• Water made as waste product.
http://www.mcgrawhill.ca/school/applets/abbi
o/quiz/ch05/how_glycolysis_works.swf
http://instruct1.cit.cornell.edu/courses/biomi2
90/ASM/glycolysis.dcr
http://programs.northlandcollege.edu/biology
/Biology1111/animations/glycolysis.html
Reduction of NAD+
• http://www.mcgrawhill.ca/school/applets/a
bbio/quiz/ch05/how_nad_works.swf
Krebs Cycle
• First Pyruvate converted to Acetyl-CoA.
• NAD + converted to NADH
• FAD converted to FADH2
• CO2 given off as waste product
• ATP produced
http://www.mcgrawhill.ca/school/applets/abbi
o/quiz/ch05/how_the_krebs_cycle_wor.swf
Electron Transport Chain and
Chemiosmosis
• NADH converted to NAD+ releasing high
energy electrons.
• FADH2 converted to FAD releasing high
energy electrons.
• H+ pumped to intermembrane space by
high energy electrons.
• H+ reenters matrix joining with electrons
and O2 to produce water.
• This converts ADP to ATP.
• When ETC is operating pH matters.
• The H+ gradient that results is called the
proton motive force.
• Force is an electrochemical gradient.
– The concentration of protons (chemical
gradient).
– Voltage across the membrane because of a
higher concentration of positively charged
charged protons on one side (electrical gradient).
• Oxidative and photo phosphorylation.
• http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites
/dl/free/0072437316/120071/bio11.swf::Electron%20Tran
sport%20System%20and%20ATP%20Synthesis
These take time to load…
• http://vcell.ndsu.nodak.edu/animations/etc/movie.htm
• http://vcell.ndsu.nodak.edu/animations/atpgradient/movie
.htm
Prokaryotes
• http://www.mcgrawhill.ca/school/applets/abbio/quiz/ch05/
electron_transport_syst38.swf
ATP Total from Cell Respiration
• 38 ATP prokaryotes
• 36 ATP eukaryotes (b/c 2 used for active
transport of NADH into mitochondria)
• 2 ATP Glycolysis;
• 2 ATP Krebs Cycle;
• 32 ATP ETC and Chemiosmosis
Regulation of Aerobic Respiration
3 points of feedback inhibition
1. Large amounts of ATP or citrate (from the
Krebs cycle) bind to and stop enzyme
phosphofructokinase from allowing glycolysis
to continue. These are allosteric inhibitors.
2. Also, large amounts of NADH inhibit
pyruvate dehydrogenase from converting
pyruvate to acetyl-CoA.
3. Finally, large amounts of ADP activate the
enzyme phosphofructokinase of glycolysis.
Oxidation without O2
Anaerobic Respiration
• Some prokaryotes use S, N, CO2, and
inorganic metals as final e- acceptors in
place of O2. Less ATP produced but enough
to be called respiration.
• Methanogens are part of Archaea and use
CO2 as e- acceptor. They convert it into CH4
or methane.
• Some prokaryotes use SO2 or other sulfates
as e- acceptor. They convert it into H2S.
Fermentation
• Process in which electrons stored in
NADH from glycolysis are recycled or
donated to organic molecules. This
converts NADH to NAD+ and allows
glycolysis to run continuously.
• Bacteria can carry out many different
types of fermentation.
Organic molecule + NADH 
reduced organic molecule + NAD+
Ethanol Fermentation
• Occurs in yeast after glycolysis.
• Yeast enzymes remove CO2 as a waste
product from pyruvate through
decarboxylation.
• The other product from decarboxylation is
a 2C molecule acetaldehyde which
accepts electrons from NADH. This
produces ethanol and NAD +.
Lactic Acid Fermentation
• The enzyme lactate dehydrogenase
converts pyruvate into lactic acid and
converts NADH into NAD+.
• Usually blood can remove the lactate,
however if this does not happen muscle
fatigue results.
Catabolism
of Proteins
and Fats
Catabolism of Proteins
• Broken down into amino acids.
• Deamination removes side amine group.
• New proteins can be made from these
amino acids.
• Some enter glycolysis or Krebs cycle to
become intermediate molecules.
Catabolism of Fats
• Broken down into fatty acids and glycerol.
• Fatty acids are converted to form acetyl-CoA
by –oxidation.
• Produce more energy per gram than
glucose.
Key intermediates connect
metabolic pathways
• Many enzymatic pathways can be used to
break down macromolecules (catabolism)
or to build up macromolecules
(anabolism).
Evolution of Metabolism
(important events)
1. Obtaining chemical energy from breaking
down organic molecules.
2. Evolution of glycolysis.
3. Evolution of photosynthesis to generate ATP.
4. The substitution of H2O for H2S to produce
O2 during photosynthesis.
5. The evolution of aerobic respiration.
6. Nitrogen fixation makes N available to
organisms.