Adenosine triphosphate - Wikipedia
Start studying photosynthesis, ATP, ADP, and AMP. Learn vocabulary, terms, and more with chemical equation for photosynthesis. chemical equation for. ATP (Adenosine tri-phosphate) is an important molecule found in all living things. from ADP, adenoside di-phosphate, to AMP, adenosine mono-phosphate. Relationships among ATP, ADP, and AMP. How is ATP recycled within cells? all have adenosine bound with phosphates with high energy bonds; recycled via.Proceso de síntesis de ATP
Naturally, molecules want to be at a lower energy state, so equilibrium is shifted towards ADP. Electrostatic repulsion of the four negative charges on the oxygens of the ATP molecule.
Naturally, like charges repel and opposite charges attract. Therefore, if there are four negative charges in close proximity to one another, they will naturally repel each other.
ATP and reaction coupling
This makes ATP a relatively unstable molecule because it will want to give away its phosphate groups, when given the chance, in order to become a more stable molecule. The oxygen molecules of the ADP are sharing electrons. Those electrons are constantly being passed back and forth between the oxygens, creating an effect called resonance.
This stables the ADP. Resonance does not occur in ATP; therefore, it is a more unstable molecule. This means that it is easier for ATP to lose one of its phosphate groups.
But, it takes a large amount of water to force ADP to lose one of its phosphates. ATP is useful in many cell processes such as glycolysisphotosynthesisbeta oxidationanaerobic respirationactive transport across cell membranes as in the electron transport chainand synthesis of macromolecules such as DNA. Macmillan Publishing Company, A number cellular respiration enzymes are controlled by the binding of regulatory molecules at one or more allosteric sites.
An allosteric site is just a regulatory site other than the active site. Binding of a regulator to the allosteric site of an enzyme changes its structure, making it more or less active. The molecules that bind cellular respiration enzymes act as signals, giving the enzyme information about the cell's energy state. ATP, for instance, is a "stop" signal: This is a case of feedback inhibition, in which a product "feeds back" to shut down its pathway. Diagram showing feedback inhibition of glycolysis, pyruvate oxidation, and the TCA cycle by the end product of cellular respiration, ATP.
Regulation of glycolysis Several steps in glycolysis are regulated, but the most important control point is the third step of the pathway, which is catalyzed by an enzyme called phosphofructokinase PFK. Citrate, the first product of the citric acid cycle, can also inhibit PFK. Diagram showing regulation of glycolysis via the enzyme phosphofructokinase PFK. PFK catalyzes the conversion of fructosephosphate to fructose-1,6-bisphosphate in glycolysis. Pyruvate oxidation The next key control point comes after glycolysis, when pyruvate is converted to acetyl CoA.
The enzyme that catalyzes the conversion reaction is called pyruvate dehydrogenase.
- Regulation of cellular respiration
- What is the energy relationship between ATP, ADP, and AMP?
- Adenosine triphosphate
So, more acetyl CoA is made when energy stores are low. Pyruvate dehydrogenase is also activated by its substrate, pyruvate, and inhibited by its product, acetyl CoA. Diagram of the regulation of pyruvate oxidation. The enzyme pyruvate dehydrogenase catalyzes the conversion of pyruvate to acetyl CoA. Citric acid cycle Entry into the citric acid cycle is largely controlled through pyruvate dehydrogenase abovethe enzyme that produces acetyl CoA.
Regulation of cellular respiration (article) | Khan Academy
However, there are two additional steps in the cycle that are subject to regulation. These are the two steps in which carbon dioxide molecules are released, and also the steps at which the first two NADH molecules of the cycle are produced.
Isocitrate dehydrogenase controls the first of these two steps, turning a six-carbon molecule into a five-carbon molecule. Diagram showing regulation of the citric acid cycle.
Putting it all together There are lots of other regulatory mechanisms for cellular respiration besides the ones we've discussed here. For instance, the speed of the electron transport chain is regulated by levels of ADP and ATP, and many other enzymes are subject to regulation.
However, these examples give you a feel for the kind of logic and strategies cells use to regulate metabolic processes. At each stage, we can see similar elements.