We’ve all heard of the Citric Acid Cycle, but have you ever stopped to consider why it’s called a cycle? Most of us have a general understanding of the process, but this article will take a deeper dive into what makes the Citric Acid Cycle a cycle, and its importance in human biology.
We’ll explore the process, the history of its name, and just why it is so important. So buckle up and get ready to get to know the Citric Acid Cycle a little bit better. Let’s begin our exploration of why it is called a cycle!
Why is the Citric Acid Cycle called a Cycle?
The citric acid cycle, also known as the Krebs cycle or tricarboxylic acid cycle (TCA), is an essential metabolic pathway for cellular respiration and energy production in living organisms.It is a complex network of chemical reactions that convert food into usable energy in the form of ATP – and this is the reason why it is one of the most important and widely studied biochemical cycles in biology. But why is the citric acid cycle called a cycle?The cycle of reactions that compose the citric acid cycle are cyclical in nature and resemble a ring, thus implying the term “cycle”.
The reactions occurring within the citric acid cycle involve the transfer of electrons and protons to create energy in the form of ATP, which in turn completes the cycle. This cycle continues and replenishes itself to keep the energy production efficient and sustained.
The Different Reactions of the Citric Acid Cycle
The whole process is composed of eight distinct reactions – four oxidation-reduction reactions and four synthesis reactions – that are repeated in a cycle to produce the energy-rich molecules. The cycle begins with the condensation of acetyl-CoA and oxaloacetate to create citrate and is completed by oxidative decarboxylation of oxoglutarate to create succinyl-CoA. The cycle also includes a number of intermediate steps which involve cell respiration and the release of carbon dioxide as a waste product.During the cycle, NAD+ and FAD are oxidized to form NADH, FADH2 and ATP, which will be used by the cell for other metabolic processes. The citric acid cycle has two main pathways which are the Embden-Meyerhof-Parnas (EMP) pathway and the pentose phosphate pathway.
The EMP pathway converts the glucose molecules into pyruvate, releasing energy and carbon dioxide from ATP. The pentose phosphate pathway is a side pathway leading from the EMP and is used for the regeneration of NADPH, an important coenzyme for synthesis and storage of glucose molecules.
Why is Citric Acid Cycle Important?
The citric acid cycle is one of the most important metabolic pathways for generating energy. It is vital for cellular respiration, which is the process that cells use to break down carbohydrates and generate ATP – the energy that keeps the cells alive and functioning. Additionally, the citric acid cycle is essential for the breaking down of fats and proteins, as well as the synthesis of important metabolites.