Does Glycolysis Occur In The Cytoplasm? 5 Facts

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Glycolysis is a definite pathway that ensures the breaking down of the glucose molecules. Let us check if it occurs within cytoplasm or not.

Glycolysis occurs within the vast organelle cytoplasm, which is an important process in generating the energy units to support the cells, that are adenosine triphosphate (ATP).

Let us check the details of the ways the process of glycolysis occurs in cytoplasm, along with the reason and the cause of its occurrence in cytoplasm.

How does glycolysis occur in cytoplasm? 

Every cellular process within cytoplasm has definite sequential activities. Let us check the way glycolysis occurs within cytoplasm. 

There is a ten-step process to establish the glycolysis process within cytoplasm, which are as follows: 

Step 1:

  • An addition of the phosphate group occurs to glucose with the aid of the enzyme named hexokinase in the cytoplasm of the cell. 
  • This group of phosphate gets transferred from ATP to glucose which helps in the formation of glucose-6-phosphate. 

Step 2: 

  • The compound Glucose-6-phosphate then gets isomerised to form fructose,6-phosphate with the aid of the enzyme named phosphoglucomutase.

Step 3:

  • Another ATP molecule gets utilised in the transfer of a phosphate group to fructose 6-phosphate in order to convert into fructose 1,6-bisphosphate by utilising the enzyme named phosphofructokinase.

Step 4:

  • The conversion of fructose 1,6-bisphosphate takes place to glyceraldehyde 3-phosphate and dihydroxyacetone phosphate through the usage of the enzyme aldolase.

Step 5:

  • The dihydroxyacetone phosphate is then converted into glyceraldehyde 3-phosphate. 

Step 6:

  • This step consists of two reactions. One is where glyceraldehyde 3-phosphate dehydrogenase ensures transferring of one hydrogen molecule from glyceraldehyde phosphate to nicotinamide adenine dinucleotide (NAD) to form the outcome NADH and H+.
  • Another is where one phosphate is added to glyceraldehyde phosphate by Glyceraldehyde 3-phosphate dehydrogenase in order to form 1,3-bisphosphoglycerate.

Step 7:

  • Phosphate is transferred from 1,3-bisphosphoglycerate with the support of phosphoglycerokinase to ADP in order to form ATP. Thus, the end products obtained are two molecules of phosphoglycerate along as well as ATP.

Step 8:

  • The phosphate collected from the two molecules of phosphoglycerate molecules are relocated to the second carbon to form two molecules of 2-phosphoglycerate by utilising the enzyme phosphoglyceromutase.

Step 9: 

  • A water molecule gets removed from 2-phosphoglycerate using enolase as the enzyme to form phosphoenolpyruvate.

Step 10: 

  • A phosphate gets transferred from phosphoenolpyruvate to ADP in order to form a pyruvate along with ATP with the support of pyruvate kinase. Two molecules of pyruvate in addition with ATP is generated as the outcomes.
does glycolysis occur in the cytoplasm
Steps of Glycolysis from Wikimedia

Why does glycolysis occur in cytoplasm?

Every process in the cell has a definite outcome. Let us check why glycolysis occurs within cytoplasm. 

The process glycolysis occurs within cytoplasm in order to break glucose molecules by the process of cleaving into two phosphorylated 3-carbon compounds. These are then oxidised to form pyruvate and two molecules of ATP to support as the energy source in the body. 

Does glycolysis occur always in cytoplasm?

Glycolysis is an important process of breaking down glucose within the cells. Let us check if glycolysis always occurs within cytoplasm or not. 

Glycolysis has been identified to be always occurring within the cytoplasm of all types of cells, both prokaryotic and eukaryotic in order to partially oxidise glucose to help in the formation of the two molecules of pyruvic acid. 

In the human cells, the pyruvic acid that is being produced in the process of glycolysis are further used in the Krebs cycle in order to facilitate the complete process of oxidation to generate energy. 

When does glycolysis not occur in cytoplasm?

Under certain circumstances, some cellular processes tend to not occur. Let us check when glycolysis does not occur in cytoplasm. 

In case of exceptions like no transport of ATPs within the cells, or insufficient availability of the enzyme pyruvate kinase can lead to an absence of glycolysis in cytoplasm, otherwise it always occur within cytoplasm in all the cells of the eukaryotes.

Where does glycolysis occur in eukaryotic cells?

There are few cellular processes that tend to not occur in eukaryotic cells but occur in prokaryotic cells and vice versa. Let us check in the case of glycolysis. 

The process of glycolysis occur in the cytoplasm of both prokaryotic and eukaryotic cells as to support the energy production by catabolizing glucose to form pyruvic acid. The outcome is then passed onto the Krebs cycle for complete oxidation for energy production. 

Conclusion 

It can be thus noted that glycolysis occurs only within the cytoplasm of the cells, in both the types, prokaryotes and eukaryotes.

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