Difference Between Glycolysis and Krebs Cycle

The main difference between Glycolysis and Krebs Cycle is that: Glycolysis is the first step of respiration in which one molecule of glucose undergoes partial oxidation to produce two molecules of pyruvic acids, ATP, NADH, and water. It is an anaerobic process that occurs in the cytoplasm of the cell.  Krebs cycle is the second step of respiration in which the pyruvic acid produced in glycolysis degrades after complete oxidation to produce carbon dioxide and water. It is an aerobic process that occurs in the mitochondria of the cell. Glycolysis is the linear sequence that does not require oxygen whereas the Krebs cycle is a cyclic sequence that requires oxygen.

What is Glycolysis?

It is an anaerobic process in which one molecule of glucose is converted into two molecules of pyruvic acids, ATP, NADH, and water. It occurs in the cytoplasm of the cell. The glucose undergoes partial oxidation to produce pyruvic acids. Glycolysis is the first step of respiration which is followed by the Krebs cycle (during aerobic respiration). The cell makes some amount of ATP in the absence of oxygen due to fermentation, as glycolysis is followed by fermentation. Glycolysis does not require oxygen. It is a linear sequence.

What is Krebs Cycle?

It is an aerobic process in which the pyruvic acid produced in the process of glycolysis degrades. It occurs in the mitochondria of the cell. The pyruvic acid undergoes complete oxidation to produce carbon dioxide and water. Krebs cycle is the second step of respiration after glycolysis. The Krebs cycle requires oxygen. It is the cyclic sequence. It is also called as Citric acid cycle or TCA. Glucose gets completely oxidized to produce acetyl CoA which enters the citric acid cycle and further combines with carbon compound oxaloacetate to form 6C citrate. In this process 2 molecules of CO₂ are released with the recycling of oxaloacetate and the energy is stored in the form of ATP, NADH, and FADH.

Similarity between Glycolysis and Krebs cycle

Both glycolysis and Krebs cycle are steps of respiration in which energy is released in the form of ATP and NADH. The process of glycolysis and the Krebs cycle both occur inside the cell of the living organism. 

Difference between Glycolysis and Krebs cycle

Glycolysis is an anaerobic process while the Krebs cycle is an aerobic process. In the process of glycolysis, glucose is converted into pyruvic acid whereas pyruvic acid obtained in the glycolysis is converted into carbon dioxide and water. In glycolysis, partial oxidation of glucose produces pyruvic acid whereas in the Krebs cycle complete oxidation of pyruvic acid produces carbon dioxide and water. Glycolysis occurs in the cytoplasm of the cell while the Krebs cycle occurs in the mitochondria of the cell. Glycolysis is the first step of respiration whereas the Krebs cycle is the second step of respiration. Glycolysis is a linear sequence and requires does not oxygen whereas Krebs cycle is a cyclic sequence which requires oxygen.

	Glycolysis	Krebs Cycle
Type of process	It is an anaerobic process.	It is an aerobic process.
Reactants and resultant products	In this process, glucose is converted into pyruvic acid.	In this process pyruvic acid obtained in glycolysis is converted into carbon dioxide and water.
Oxidation	Partial oxidation of glucose produces pyruvic acid.	The complete oxidation of pyruvic acid produces carbon dioxide and water.
Occurs in which part	It occurs in the cytoplasm of the cell.	It occurs in the mitochondria of the cell.
Type of sequence	It is a linear sequence.	It is the cyclic sequence.
Oxygen requirement	It does not require oxygen.	It requires oxygen.
Step of respiration	It is the first step of respiration.	It is the second step of respiration.
Occurs in which type of organisms	It occurs in all living organisms.	It occurs in the aerobes.

FAQs on Glycolysis and Krebs Cycle

Question1: What is Glycolysis?

Answer: 

Glycolysis is an anaerobic process in which glucose is partially oxidized to produce pyruvic acid. 

Question 2: Which product undergoes Partial Oxidation in Glycolysis?

Answer:

In the process of glycolysis partial oxidation of glucose is done to form 2 pyruvic acids.

Question 3: What is the Krebs cycle?

Answer:

Krebs cycle is an aerobic process in which pyruvic acid obtained in the glycolysis undergoes complete oxidation to produce carbon dioxide and water.

Question 4: What are the Products released after the Completion of the Krebs cycle?

Answer:

The products released after the completion of the Krebs cycle are carbon dioxide, water, and energy in the form of ATP, NADH and FADH.