hello friends this is seher from easy peasy and the topic that we are going to discuss today is called as atp adp energy cycle now this cycle have four different type of steps the first step is that salt produces atp in their mitochondria and then this atp will get delivered inside the cytoplasm inside the cytoplasm this atp is going to couple itself with some endergonic reactions and then it will convert itself into adp and inorganic phosphate with the release of energy the fourth and last step is that adp and inorganic phosphate will get recycled to make atp now we will discuss each side in more detail so let's start with the left hand side so we are going to see how adenosine diphosphate and inorganic phosphate will make atp this type of reaction is called as phosphorylation and this is an endergonic reaction it means that it will need energy in order to make atp from adenosine diphosphate in heterotrophs we have two different type of phosphorylation one is called as oxidative phosphorylation and the second type is substrate level phosphorylation oxidative phosphorylation is the main phosphorylation so 90 percent of atp is going to get produced from oxidative phosphorylation and substrate level phosphorylation produces only 10 percent of atp so it has a minor importance but it will become a major important factor when a muscle is in constant exertion and requires more atp than generated from mitochondria oxidative phosphorylation usually occur inside the mitochondria that's why the mitochondria is also called as powerhouse of the cell and atp is called as the energy currency of the cell the substrate level phosphorylation usually occurs within the cytoplasm of a cell by the process called as glycolysis or krebs cycle let's discuss the substrate level phosphorylation in little bit more detail now if you look at this picture you can see that substrate level phosphorylation means a direct transfer of a phosphate group from substrate to adp as you can see in this picture we have an enzyme and this enzyme has two different sites one side is occupied by a substrate that has a phosphate group attached with it and the other side is occupied by adenosine diphosphate with the help of the enzyme this phosphate group is going to get directly transfer from this substrate into adp converting itself into adenosine triphosphate and the substrate will release itself from the enzyme the two most common examples of the substrate level phosphorylation are here the first example is phosphenol pyruvate now this is a substrate that is having a phosphate group attach itself with it with the help of pyruvate kinase it will release its phosphate group and let it attach itself with adenosine diphosphate converting it into adenosine triphosphate the second example is 1 3-bis phosphoglycerate now in this compound we have this phosphate group that is going to get donated by this substrate to adp converting itself into atp and the substrate will convert itself into 3 phosphoglyceric acid substrate level phosphorylation usually occurs inside the cytoplasm by the process called as glycolysis because glycolysis is the first step of both aerobic and anaerobic respiration so in the process of glycolysis four atp molecules are generated the next type is oxidative phosphorylation in oxidative phosphorylation protons and electrons create a kind of gradient inside the cell which is going to produce a proton motive force that is going to help the atp synthase to convert adp into atp this type of process is called as electron transport chain as you can see over here that the citric acid cycle is going to produce the substrates called as nadh and fedh2 with the help of protons and electrons that is going to transfer from one transmembrane protein into another transmembrane protein and this gradient is going to help atp synthase to convert adp into atp the details of this electron transport chain will be discussed in a separate video now up till now we discussed the phosphorylation of atp adp energy cycle let's move on towards the right hand side so if we say that atp is converting into adp that process is called as hydrolysis and as it is going to release energy so the reaction is exergonic now let's see how atp is converting itself into adp so we have adenosine triphosphate here and we already know the structure of atp from the last video if you didn't watch the last video the link will be given in the description box so this atp has a ribose sugar attached itself with adenine nitrogenous base and three phosphate group that's why it is called as atp now this negative 4 is basically the charge present on each oxygen so we can see there are four negative charge that is why atp negative 4 is represented here now hydrolysis means that we need water molecules so these are the water molecules we are going to use now each water molecule have oxygen that is having two lone pairs on it and as we know that water molecules make hydrogen bonds with each other so these intermolecular interactions can also occur between these two water molecules so if we say that this lone pair of this oxygen is going to interact with hydrogen over here by this way this oxygen will get the liberty to have its lone pair attack the phosphate group present in atp molecule now phosphate belongs to graphite that is why it is making five bonds two with this oxygen and one one with these three oxygen so it cannot handle the sixth bond that is created by this oxygen now this phosphate group is unstable so the electrons that are sharing between this phosphate group and oxygen will go back to the oxygen and the bond will be break from here and as a result we have adenosine diphosphate with an inorganic phosphate here from here the adenosine diphosphate will go under the process called as ionization and will release this proton that is attached with oxygen atom over here and this inorganic phosphate will go under the resonance stabilization so this hydrogen is basically not present with one oxygen rather it is going to relocate itself with all the oxygen and provide stability to this inorganic phosphate group here with the release of free energy now the question is how much energy is going to get released from atp hydrolysis let's assume that atp is in a constant equilibrium state so we will take all the values at a standard level and by this way if we try to find the delta g naught value the value will come under negative 28 to negative 34 kilojoule per mole but this is not the case because atp cannot present in an equilibrium state it depends on certain different things that how much energy is going to get released from atp molecule it depends on the type of cell the atp hydrolysis takes place it also depends on the concentration of atp adp and inorganic phosphate in that location because as we know that the concentration of atp adp and inorganic phosphate is higher in mitochondria than in cytoplasm it also depends on the concentration of magnesium ion because magnesium can also attach itself with atp and adp the reason of attaching of magnesium ion with atp and adp is to provide stability to these molecules and also to prevent the unnecessary bonding of these oxygens present on atp and adp with the enzyme now let's see how this magnesium ion is going to get attached itself with adenosine triphosphate and adenosine diphosphate so if we talk about the major production of atp so we will go towards mitochondria now as we know over here that atp is coming from mitochondria so it will pass through the membrane and will gum itself into the cytoplasm inside the cytoplasm this atp will get attached itself with the magnesium ion that is already present in the cytosol now this mgatp will undergo in the process of metabolism or couple itself with some endergonic reactions and will convert itself into mgadp now over here this magnesium ion will get detached from adp and will get stored back in the cytoplasm this adp will go back into the mitochondria by adp-atp carrier so now this adp is present inside the matrix inside the matrix of mitochondria we also have magnesium ions that will attach itself with adp now here the inorganic phosphate group from metabolism is going to come inside the matrix from phosphate carrier so now this phosphate group will attach itself with adp with the help of atp synthase now this atp will convert itself into atp negative 4 charge and will go back into the cytoplasm now in order to calculate how much energy is going to get produced by atp hydrolysis let's take a specific cell and see how much energy is going to get produced by atp hydrolysis so for example we are taking red blood cells of human so if we take the human erythrocyte we can see the concentration of atp adp and phosphate groups are here and if we put these values in the equation with standard ph and temperature we can see that the delta g value will be negative 52 kilojoule per mole that is a lot different than negative 28 to negative 34 generated by delta g naught value so a lot of amount of energy is going to get produced from atp hydrolysis and we need these atp hydrolysis every second some of our organelles are working constantly and some of our organelles are working to our will thanks to our creator for this complicated system that are working just fine that's it for now thank you very much for watching this video take care bye for now [Music] you