Adenosine triphosphate ATP is the energy currency for cellular processes. ATP provides the energy for both energy-consuming endergonic reactions and energy-releasing exergonic reactions, which require a small input of activation energy.
When the chemical bonds within ATP are broken, energy is released and can be harnessed for cellular work. The more bonds in a molecule, the more potential energy it contains. Because the bond in ATP is so easily broken and reformed, ATP is like a rechargeable battery that powers cellular process ranging from DNA replication to protein synthesis.
Adenosine triphosphate ATP is comprised of the molecule adenosine bound to three phosphate groups. Adenosine is a nucleoside consisting of the nitrogenous base adenine and the five-carbon sugar ribose. The three phosphate groups, in order of closest to furthest from the ribose sugar, are labeled alpha, beta, and gamma. One example of energy coupling using ATP involves a transmembrane ion pump that is extremely important for cellular function.
The pump works constantly to stabilize cellular concentrations of sodium and potassium. This process of a phosphate group binding to a molecule is called phosphorylation. ATP performs cellular work using this basic form of energy coupling through phosphorylation. The hydrolysis of one ATP molecule releases 7.
If it takes 2. Often during cellular metabolic reactions, such as the synthesis and breakdown of nutrients, certain molecules must be altered slightly in their conformation to become substrates for the next step in the reaction series. One example is during the very first steps of cellular respiration, when a molecule of the sugar glucose is broken down in the process of glycolysis. In the first step of this process, ATP is required for the phosphorylation of glucose, creating a high-energy but unstable intermediate.
This phosphorylation reaction powers a conformational change that allows the phosphorylated glucose molecule to be converted to the phosphorylated sugar fructose. Fructose is a necessary intermediate for glycolysis to move forward. If a metabolic reaction is aerobic, it requires oxygen. Buy why? Here's an analogy.
Think about lighting a campfire. What do you need? You need fuel the wood , you need heat it's harder to light a fire when it's cold , and you need oxygen because another word for burning is " oxidizing " and, as you might guess, it can only occur in the presence of oxygen.
Each ATP molecule can then be transported elsewhere within the cell and used where needed. The energy-carrying part of an ATP molecule is the triphosphate "tail". Three phosphate groups are joined by covalent bonds. The electrons in these bonds carry energy. Within the power plants of the cell mitochondria , energy is used to add one molecule of inorganic phosphate P to a molecule of adenosine diphosphate ADP. At the energy-requiring site, the last phosphate group in the tail is broken off and the energy in the bond liberated.
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