Cellular Respiration and Fermentation Plant Biology 1

Respiration and Fermentation Process of converting glucose to a useable form of energy Respiration uses Oxygen and is very efficient Fermentation does not need Oxygen but is very inefficient

ATP Adenosine Tri-phosphate A compound that “powers” the cell All cell parts need ATP to work properly Without ATP, the cell dies.

Glycolysis, Cell respiration or fermentation ATP So where can we get ATP? Glycolysis, Cell respiration or fermentation

Glycolysis Cells cannot break down large compounds Glucose must be changed so the cell can use it. Through a series of chemical reactions, glucose is changed to pyruvic acid During this process, 6 molecules of ATP are produced (8 are produced, but 2 are used up)

Pyruvic acid Energy compound produced at the end of glycolysis

2 ATP’s used Glucose 8 ATP’s produced Glycolysis Pyruvic Acid

Respiration (an aerobic process) Process of converting pyruvic acid to ATP in the presence of oxygen One pyruvic acid molecule can produce 30 molecules of ATP By-product of respiration is CO2 + H20 Takes places inside each cell, in the mitochondria (organelle)

C6H12O6 + 6O2= 6CO2 +6 H2O This reaction produces 30 ATPs! Respiration C6H12O6 + 6O2= 6CO2 +6 H2O This reaction produces 30 ATPs!

2 ATP’s used Glucose 8 ATP’s produced Glycolysis Pyruvic Acid Respiration 30 ATP’s produced CO2 and H2O

What if there is no, or not enough oxygen? Fermentation

Fermentation (an anaerobic process) Process of producing some ATP without oxygen present Much less efficient Only 2 ATP’s are produced from each glucose molecule All cells are capable of fermentation Two types Lactic Acid fermentation Alcoholic fermentation

Lactic Acid Fermentation “Feeling the burn!” When a cell runs out of oxygen, it makes ATP by repeating the glycolysis process. Fermentation replaces a special compound lost during glycolysis Fermentation does not produce ATP, but merely allows the cell to go through the glycolysis process repeatedly.

Lactic Acid fermentation Fermentation uses sugar much faster than respiration This is why exercise is better if your cells are functioning in this mode (anaerobic). Lactic acid and carbon dioxide are the by products of fermentation. If you produce them, your body must get rid of them quickly, or they can cause damage to your cells.

Alcoholic Fermentation Similar to lactic acid fermentation, but the by-product is ethyl alcohol, instead of lactic acid, and carbon dioxide The carbon dioxide produces the air spaces in bread, and the ethyl is the toxin that impairs brain function when consumed.

Ethyl alcohol or lactic acid and CO2 2 ATP’s used Glucose 8 ATP’s produced Glycolysis 2 ATP’s produced Pyruvic Acid Is oxygen present? No Yes Fermentation Respiration 30 ATP’s produced Ethyl alcohol or lactic acid and CO2 CO2 and H2O

Something to think about What is the advantage of aerobic respiration vs anaerobic? Why wouldn’t all cells just do aerobic? In what situations would anaerobic be better?