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Cellular Respiration

Glycolysis














Home | Key Terms/ Key Words | What happens before cellular respiration? | Glycolysis | Transition Reactions | Kreb's Cycle | The electron transport chain | Fermentation





The First Phase Of Cellular Respiration
















Glycolysis has two parts; part one and two.
Gylcolysis one is a series of exothermic reactions. In order to start gylcolysis one you need energy (ATP). It comes from the first reaction in gylcolysis one, called substarte level phosphorylation. In this reaction, an enzyme takes a phosphate from one sulphate to another. It removes a phosphate to glucose and creates glucose-6-phosphate. Then the glucose-6-phosphate is changed into fructose-6-phosohate, and is then changed into fructose-1,6-diphosphate. The fructose-1,6-diphosphate is then rearranged to form two molecules of PGAL.
 
Gylcolysis Two consists of a series of exothermic reactions. After gylcolysis one, each PGAL is oxidized. The electrons are taken up by NAD that is eventually reduced. A hydrogen ion is then attached to the NAD molecule to create NADH. The PGAL can now take another phosphate ion from the cytosol of the cell to form PGAP(1,3-diphosphoglcerate). After PGAP is formed two molecules of ADP remove a phosphate group from PGAP and form PGA. Here, substrate level phosphorylation creates two molecules of ATP (one for each molecule of PGAP). The molecules of PGA are oxidized and release two water molecules and form PEP. Then another substrate level phosphorylation happens. Two ADP molecules remove the phosphates from the PEP and form two ATP molecules. The final product of glycolysis one and two is pyruvic acid.
















Glycolysis one and two:
 
 
 
Glucose
Glucose-6-phosphate
Fructose-6-phosphate
fructose-1,6-diphosphate
PGAL (phosphogylceraldehyde)
NADH ADDED
PGAP (1,3-phosphogylceraldehyde)
2 ADP ADDED
PGA (phosphoglycerate)
2 WATER MOLECULES RELEASED
PEP
2 ADP ADDED
Pyruvic acid