Cellular Respiration
Cellular Respiration
Process by which cells release energy from molecules of food.
Carbohydrates, fats and proteins all contain energy
This energy is released gradually in a series of reactions controlled by enzymes.
Release energy is stored as ATP for later use.
ATP is the currency of the cell.
The Chemical Equation
C6H12O6 + 6 02 6CO2 + 6H2O + 38 ATP Glucose + Oxygen
Carbon Dioxide + Water + Stored Energy 2 ATP are used to make this process take place Net Gain = 36 ATP for 1 molecule of Glucose
4 Main Steps in Respiration
Glycolysis Intermediate
Reaction Krebs Citric Acid
Cycle Electron Transport
System
Glycolysis
2 ATP are used to start the process
Glucose is split into 2 3-carbon pyruvic acid molecules
Some Hydrogen is released
4 ATP are made, a net gain of 2 ATP
It occurs in virtually all cells.
In eukaryotes, it occurs in the cytosol.
http://www.science.smith.edu/departments/Biology/Bio231/glycolysis.html
Intermediate Reaction
Takes place in the mitochondria (powerhouse of the cell)
Breakdown of the 2 3-carbon pyruvic acid molecules
2 carbon fragments, acetic acid are formed and
2 CO2 and more hydrogen are released Acetic Acid is carried by Acetyl CoA to
Kreb Cycle
Krebs Citric Acid Cycle
Breakdown Continues
Four more CO2 are released
Many more Hydrogen are released and picked up by NAD+ to form NADH
Two more ATP are made
http://www.science.smith.edu/departments/Biology/Bio231/krebs.html
Electron Transport System
Hydrogen atoms are transferred to bond with oxygen atoms to make water
32 ATP are made e- power e- carriers Water wheel
Net Result 36 ATP produced
Oxygen is vital! It is the final acceptor
of electrons – without it the process stops.
Pyruvic acid is converted to lactic acid, which accumulates in muscles causing fatigue and soreness.
http://www.science.smith.edu/departments/Biology/Bio231/etc.html