Depending on the number of phosphate groups attached to the sugar moiety, a nucleotide may be called nucleoside monophosphate if with only one phosphate group , nucleoside diphosphate with two phosphate groups , or nucleoside triphosphate when with three phosphate groups. Depending on the pentose sugar component, a nucleoside may be a ribonucleoside or a deoxyribonucleoside.
A ribonucleoside is a nucleoside with a ribose sugar component. Based on the nucleobase component, the ribonucleoside may be adenosine , guanosine , cytidine , uridine , or 5-methyluridine.
A deoxyribonucleoside is a nucleoside with a deoxyribose sugar. Similarly, depending on the nucleobase component, a deoxyribonucleoside may be deoxyadenosine , deoxyguanosine , deoxycytidine , thymidine , or deoxyuridine. Adenosine diphosphate ADP is a nucleoside phosphate comprised of a ribonucleoside and two phosphate groups. It means it has a ribose as its sugar and two phosphate groups attached. Its nucleoside contains a purine base, i.
It has two phosphate groups attached to the nucleoside. It can be interconverted to ATP. When the cell has extra energy gained from breaking down food that has been consumed or, in the case of plants, made via photosynthesis , it stores that energy by reattaching a free phosphate molecule to ADP, turning it back into ATP. The ATP molecule is just like a rechargeable battery.
There are times when the cell needs even more energy, and it splits off another phosphate, so it goes from ADP, adenoside di-phosphate, to AMP, adenosine mono-phosphate. Think of the others as different brands of rechargable batteries that do the same job. What about oxygen? Why do we need that?
What happens if you put a glass over a candle? You starve the fire of oxygen, and the flame flickers out. If a metabolic reaction is aerobic, it requires oxygen. Breaking one phosphoanhydride bond releases 7. ATP is the primary energy transporter for most energy-requiring reactions that occur in the cell.
For example, it takes only a few seconds for half of the ATP molecules in a cell to be converted into ADP to be used in driving endergonic non-spontaneous reactions and then converted back into ATP using exergonic spontaneous reactions. ATP is useful in many cell processes such as glycolysis , photosynthesis , beta oxidation , anaerobic respiration , active transport across cell membranes as in the electron transport chain , and synthesis of macromolecules such as DNA.
Introduction ATP is an unstable molecule which hydrolyzes to ADP and inorganic phosphate when it is in equilibrium with water. The adenine ring is at the top, connected to a ribose sugar , which is connected to the phosphate groups. Used with permission from Wikipedia Commons. Why is ATP hydrolysis an exergonic reaction?
Therefore, due to thermodynamics , the reaction spontaneously occurs because it wants to be at a higher entropy level.
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.
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