What is the use of atp? give three examples of how atp is used in the cell.
The cell doesn’t have to make ATP from scratch every time it needs some energy. Like a rechargeable battery, ATP can also be recharged and reused. Show ADP, the “uncharged” version of the molecule, stands for adenosine diphosphate. The word diphosphate indicates that the molecule has 2 phosphate (PO3) groups. To “charge” ADP, the cell adds a third phosphate group, converting ADP to ATP. ATP stands for adenosine triphosphate. The word triphosphate indicates that the molecule has 3 phosphate groups. ATP stores energy within the bonds between phosphate groups, especially the second and third. This bond is a source of potential chemical energy, and it’s kind of like a compressed spring. Getting the energy back out requires a protein (or in some cases RNA) that (1) breaks the third phosphate group off and (2) uses the energy released, like when a spring uncoils, to do something: drive a chemical reaction, move part of the protein, or transport something (see below). The cell can make and break ATP extremely quickly. A working muscle cell makes and uses about 10 million molecules of ATP every second! The ADP portion of the molecule stays the same. Adding a third phosphate group (phosphorylation) adds energy, like compressing a spring. Removing the phosphate group (hydrolysis) releases energy, like freeing a spring to uncoil. Top Uses for ATP
Two Ways for Making ATPAs our cells oxidize carbon-based molecules from our food, some of the energy held within their chemical bonds is released. Our whole complex metabolic system is arranged to capture some of this energy and put it to work. If ATP is like a battery, then cellular respiration is like a battery charger. Our cells have two ways to make ATP: substrate-level phosphorylation and oxidative phosphorylation. Plants have a third. During photosynthesis, they use energy from sunlight to make ATP. Substrate-level PhosphorylationThis process involves an enzyme (a type of protein) which transfers a phosphate group from a substrate (in this case, a carbon-based molecule from food) to ADP. The ATP generated during glycolysis and the citric acid cycle come about in this way, accounting for 4 ATPs per glucose molecule. Oxidative PhosphorylationThis process generates most of the ATP we use—up to 27 for each molecule of glucose. As enzymes break apart the molecules from food, they transfer hydrogen atoms (made of a proton and an electron) to the carrier molecules FAD and NAD. The carriers deliver these protons and electrons to the mitochondrial membrane. The movement of electrons along the electron transport chain powers pumps that move protons into the space between the two mitochondrial membranes. The protons then diffuse back across the membrane through ATP synthase, a remarkable molecular machine that uses the energy from proton diffusion to “charge” molecules of ATP. Substrate-level Phosphorylation Oxidative Phosphorylation ATP is a NucleotideATP not only stores energy, it is one of the building blocks of RNA—along with UTP, CTP, and GTP. Molecular machines inside all cells, called RNA polymerases, link these building blocks together into long chains to make messenger, transfer, ribosomal, and other types of RNA. Each nucleotide holds the energy needed to add itself to the growing chain. As RNA is being built (a process called transcription), two phosphates are cleaved off the incoming nucleotide, and the energy from that bond is redirected into forming a new bond with the nucleotide in front of it. DNA is built using a similar process, only the building blocks are dATP, dTTP, dCTP, and dGTP. The “d” indicates that the nucleotides contain the sugar deoxyribose instead of ribose (the difference is that deoxyribose has one less oxygen atom). Like ATP, GTP can also be used to hold and transfer energy. During the citric acid cycle, for example, GTP acts as an intermediate energy holder, ultimately transferring its third phosphate group to ADP to generate ATP. GTP also powers some of the steps of protein synthesis. What is ATP and how is it used?Adenosine 5′-triphosphate, abbreviated ATP and usually expressed without the 5′-, is an important “energy molecule” found in all life forms. Specifically, it is a coenzyme that works with enzymes such as ATP triphosphatase to transfer energy to cells by releasing its phosphate groups.
What are 3 types of work that ATP is involved in?The work that ATP does falls into three general categories: chemical, mechanical, and transport. In other words, the energy from ATP can be used to drive a chemical reaction, move something, or push a molecule from one side of a membrane to another.
What are the 3 main sources of ATP in our body?In general, the main energy source for cellular metabolism is glucose, which is catabolized in the three subsequent processes—glycolysis, tricarboxylic acid cycle (TCA or Krebs cycle), and finally oxidative phosphorylation—to produce ATP.
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