Glycolysis: What is it? Function, Steps, Types and Differences

It is the main pathway for glucose metabolism and is produced in the cytosol of all cells.


Glycolysis produces energy in the form of adenosine triphosphate (ATP). During the process, glucose is oxidized to lactate or pyruvate.

Steps of glycolysis

Glycolysis is an extramitochondrial pathway and is carried by a group of eleven enzymes. Glucose is converted to pyruvate in 10 steps by glycolysis. The glycolytic pathway can be divided into two phases:

Preparatory phrase

This phase is also called the  glucose activation phase . In the preparatory phase of glycolysis, two ATP molecules are inverted and the hexose chain splits into two triose phosphates.

During this, glucose phosphorylation and its conversion to glyceraldehyde-3-phosphate takes place. Steps 1, 2, 3, 4, and 5 together are called the preparatory phase.

Payment phase

This phase is also called the energy extraction phase. During this phase, the conversion of glyceraldehyde-3-phosphate to pyruvate and the coupled formation of ATP takes place.

Because glucose splits to produce two molecules of D-Glyceraldehyde-3-phosphate, each step in the payment phase occurs twice per glucose molecule. Steps after 5 constitute the payment phase.

Types of glycolysis

There are two different pathways by which the glycolysis process takes place. One is aerobic and the other is anaerobic.

Aerobic glycolysis: occurs when oxygen is abundant. The end product is pyruvate along with the production of eight ATP molecules.

Anaerobic glycolysis: occurs when oxygen is scarce. The end product is lactate along with the production of two ATP molecules.

Glycolysis through aerobic glycolysis occurs when oxygen and hydrogen atoms join together to break down glucose and facilitate energy exchange.

It is a metabolic pathway that involves the transformation of glucose into pyruvate and the subsequent conversion of pyruvate to lactate, in the absence of oxygen.

Anaerobic glycolysis is the transformation of glucose into lactate when limited amounts of oxygen (O2) are available. This type of glycolysis is just an effective means of energy production during short, intense exercise, providing energy for a period ranging from 10 seconds to 2 minutes.

The anaerobic glycolysis system is dominant from approximately 10 to 30 seconds during maximal effort. It is replenished very rapidly during this period and produces 2 ATP molecules per glucose molecule or approximately 5% of the energy potential of glucose (38 ATP molecules).

Analysis generation is thought to be the main means of energy production in organisms that previously had a high concentration in the atmosphere and an older form of energy production in cells.

Differences in between anaerobic and aerobic glycolysis

The main difference between anaerobic and aerobic glycolysis is that sugar is not completely broken down in the latter. Instead, it turns into lactic acid or ethyl alcohol. However, many animals and plants use the anaerobic pathway for the production of ATP.

Another difference between aerobic and anaerobic glycolysis has to do with the presence or absence of oxygen. If oxygen is involved, then the process is called aerobic; otherwise, without oxygen, the process becomes anaerobic.

The by-products of each process are also involved. Aerobic glycolysis has carbon dioxide and water as by-products, while anaerobic glycolysis generates by-products such as ethyl alcohol in plants and lactic acid in animals.

Aerobic glycolysis is used for the first time in any activity, and the phosphocreatine system helps during activities that last no more than thirty seconds. Anaerobic glycolysis kicks in during long-lasting activities, helping the body’s muscles use energy.