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