Glycolysis vs Fermentation: Definition, Function, and Steps

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Glycolysis: (anaerobic, occurs in the cytoplasm) Can be performed in all cells.

Phosphorylated molecules cannot diffuse through the membrane.

The process of ATP production in glycolysis is called Substrate-level phosphorylation.

Glycolysis - Definition and Examples - research tweet

Net Glycolysis Equation

Glucose + 2ATP + 2NAD+ + 4ADP + 2Pi = 2pyruvate + 2ADP + 2 NADH + 2H+ + 4ATP + 2H2O

Reduced Glycolysis Equation

Glucose + 2NAD+ + 2ADP + 2Pi = 2pyruvate + 2NADH + 2H+ + 2ATP + 2 H2O

"In Glycolysis, 2 net ATP (4 total made, but 2 needed to complete this stage)"

2 NADH produced (making 4 ATP in ETC for eukaryotes and 6 ATP for prokaryotes) via reduction of NAD+

2 pyruvate (3 carbons) produced Pyruvate can then be converted into various products:

1. It can be oxidized to give the acetyl group of acetyl- coenzyme A, which is then oxidized completely to give CO2.

2. It can be reduced to lactate (a type of fermentation).

3. It can be converted to ethanol and CO2 (another type of fermentation)

ADP & AMP is a activator for glycolysis

ATP and Citrate are inhibitors for glycolysis In order for glycolysis to continue operating the produced NADH must be oxidized back into NAD+

Fructose can enter glycolysis as fructose 6-phosphate!!


Fermentation is anaerobic, occurs in the cytoplasm.

It includes the process of glycolysis

Animal tissues reduce pyruvate to lactate under anaerobic conditions, at the same time oxidizing NADH back to NAD+, which is needed for continued glycolysis.

Reaction is catalyzed by lactate dehydrogenase. Lactate can be recycled; it is carried in blood to the liver where it is converted back to glucose (in a process requiring the input of energy).

The acidification of muscle explain why continued exercise can cross cramping, aka Acidosis.

Yeast produce ethanol and CO2

0 ATP is produced.

Low [NAD+]/High [NADH] is a driver for fermentation

Pyruvate Decarboxylation

Aerobic, occurs in the cytoplasm for prokaryotes, mitochondrial matrix for eukaryotes).

Both pyruvate and NADH move through the mitochondrial membrane through a large membrane protein called porin.

The inner mitochondrial membrane, however, is less permeable.

Although pyruvate moves into the matrix via facilitated diffusion, each NADH (depending upon the mechanism used for transport) may or may not require the hydrolysis of ATP (this is why the NADH in glycolysis only produce 4 ATP instead of 6).

Pyruvate decarboxylation is the biochemical reaction that uses pyruvate to form acetyl-CoA, releasing NADH, a reducing equivalent, and carbon dioxide


2 CO2

0 ATP produced

2 NADH produced, for the decarboxylation of both pyruvate (making 6 ATP in ETC)

Glycolysis vs Fermentation Citations


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