Difference Between Krebs and Calvin Cycle

Krebs vs Calvin Cycle

Biochemical pathways are extremely important processes to maintain the life on Earth. The Krebs and Calvin cycles are two very important biochemical pathways occurring inside organelles of cells. Both these processes are cyclic, but there are many differences between Krebs and Calvin cycles. The places that these processes take place, and the consumption or production of energy are different from each other. This article includes additional differences between Krebs and Calvin cycles those would be interesting to follow.

What is Krebs Cycle?

Krebs cycle is simply a part of the aerobic respiration process that is taking place in cells. Production of carbon dioxide and ATP (adenosine triphosphate) with some other by-products takes place during the whole process of cellular respiration and Krebs cycle is an important part of that. Organisms store the energy in the form of ATP. The process is known by many different names such as Citric acid cycle, Tricarboxylic acid cycle, or Szent-Gyorgyi–Krebs cycle, but all these names are referred to one process. Since many types of organisms being aerobic (plants, animals, microorganisms), the Krebs cycle takes place in all those organisms. Krebs cycle is a vital step of the respiratory pathway where Acetyl coenzyme A is broken down with oxygen that leads to release energy to produce ATP molecules. However, Acetyl coenzyme A is a produced from the respiratory substrates such as glucose, amino acid, or fats. However, it does not operate in the absence of oxygen. The respiratory substrates are broken down in the Krebs cycle. Since the Krebs cycle involves both breakdown (catabolic) and synthesis (anabolic) steps, it is known as an amphibolic pathway. The whole process has been named after Hans Krebs, who won the Nobel Prize in 1953 discovered it.

What is Calvin Cycle?

Calvin cycle is a vital step of the dark reaction of the photosynthesis that is taking place in the stroma of the chloroplast of green plants. Calvin cycle is a cyclic biochemical pathway where oxygen is produced, and carbon dioxide is used. As per the definition, Calvin cycle is a set of reactions taking place in the dark reaction of the photosynthesis, which means that it does not require sunlight. The activation of electrons does not take place in the Calvin cycle, but the necessary energy requirements for the processes are fulfilled by the consumption of ATP. Overall, it is an anabolic pathway, which forms glucose from carbon dioxide and water. However, the produced carbohydrates in the Calvin cycle are not hexose sugars (glucose with six carbons) according to the latest textbooks, but those are triose (three-carbon) sugar phosphates, aka triose phosphates. Later, it leads to produce hexose sugars in the mitochondria.

Krebs Cycle vs Calvin Cycle

Krebs Cycle

Calvin Cycle

Part of the aerobic respiration process

Part of the dark reaction of photosynthesis

Takes place in the matrix of the mitochondria

Takes place in the stroma of chloroplast

Leads to synthesize ATP

ATP is spent for the process

Takes place in all the organisms with aerobic respiration

Takes place only in the photosynthetic plants

Carbon dioxide is produced

Carbon dioxide is used

The process does not take place without oxygen

The process does not demand the presence of oxygen