ATP
Created | Updated Oct 7, 2002
ATP – Adenosine triphosphate - not very good, but i tryed :)
Atp (adenosine triphosphate) is required in all living cells as a continual supply of energy, to be used in processes, which keep the organism alive. ATP is a mononucleotide molecule made of three main components, the base (adenine), a phosphate chain and a ribose sugar backbone.
The first step in the production of ATP and the store of energy is Glycolysis and occurs in both aerobic respiration and anaerobic respiration. In both cases Glycolysis takes place in the cytoplasm of the cell, mostly because glucose is too big to get in to the mitochondria and because even before the prokaryotic mitochondria organelle invaded the cell, this process was taking place.
The process starts with glucose (a six carbon sugar) and two ATP molecules needed to kick-start the process by transferring glucose in to Fructose Bisphoshate another six-carbon sugar. The breaking of the Fructose Bisphoshate into two three carbon sugars called Pyruvate produces two ATP molecules per Pyruvate by the condensation reaction of a phosphate group (phosphorolation occurs) and a ADP (adenosine diphosphate). The excess hydrogen ions are removed by the aid of NAD to form one molecule of reduced NAD per pyruvate.
If the organism is anaerobic or when the supply of oxygen is not high enough for the energy consumption taking place, the NAD supply must be replenished, this involves oxidising the NAD and transferring the hydrogen to another molecule. This may be done in two ways, Lactose fermentation (producing Lactic acid) or alcoholic fermentation (producing Ethanol). Neither of these produces anymore ATP, meaning the gross product (as four are made but two ATP molecules must be used to start the process) of anaerobic respiration is only two ATP.
Mammals who need to respire anaerobically produce lactic acid. This process occurs by the three carbonic sugar Pyruvate being reduced into Lactic acid by the addition of the hydrogen ion from reduced NAD. One molecule of lactic acid is made for every pyruvate and there are two pyruvates per glucose put in. This build up of acid in the muscles causes a fall in pH, which in turn causes cramps and pains to occur. The lactic acid may be removed quickly when oxygen levels are restored.
This makes the over all reaction:
Yeast who need to respire anaerobically produce ethanol. This process occurs the same way except Ethanol (two carbon back bone) is produced and carbon dioxide is given off as another waste product.
This makes the equation:
However if the organism is not anaerobic then further processes may take place and produce more ATP molecules (about another 34 - 36 molecules, as two already produced). These processes take place in the mitochondria but the pyruvate molecule is too big so must again be broken down into acetylcoenzyme (Acetyl CoA) (a two carbon molecule). This “Link” reaction is catalysed by the enzyme CoA. The extra hydrogen is reduced on to NAD to form, reduced NAD. The extra carbon and two oxygen atoms are removed (oxidative decarboxylation) to form carbon dioxide, which is exhaled through the lungs and removed from the body. The molecule is now small enough to travel through the membrane into the matrix, where Krebs cycle takes place.
At the Krebs cycle the CoA enzyme enters the Acetyl into the Krebs cycle, then returns to the cytoplasm to transport another Acetyl. Each time the cycle is completed one ATP molecule is produced by substrate level phosphorolation (see below for more details)
The Last process takes place on the Christi of the mitochondria and is called the Electron Transport Chain. This is the most efficient stage of respiration where around thirty-two molecules of ATP may be produced via a series of redox (oxidation and reduction reactions) reactions. (See diagram below) – The hydrogen ions are brought by the reduced NAD and reduced FAD; this replenishes the cells supply of hydrogen carriers. The hydrogen atoms are brought at different energy levels depending on the carrier (NAD at the higher energy level). Once these hydrogen ions (+) are on the electron transport chain they moved along the chain, this happens because each successive carrier on the chain has a higher electro negativity than the carrier one before it, therefore the positive hydrogen ions are pulled along down the chain. While there are being pulled along they participate in a series of redox reactions, which join the free phosphorous groups to ADP molecules to form the end ATP.
At the last electron carrier, the cytochrome oxidase oxygen is used to get rid of the left over hydrogen ions (+), by joining together to form water as they are acidic and a build up would cause problems. This is why when a person is suffocated respiration must stop.
ATP is only produced, as it is required. It releases energy by breaking off the last phosphate group on the phosphate chain, attached with a very unstable covalent bond; the bond is broken by hydrolysis (the addition of water) releasing around 30 kJ of energy (a exergonic reaction). This leaves adenosine diphosphate (ADP), while the phosphate group usually joins with a hydrogen atom to form orthophosphate (HPO4).
ATP + H2O ADP + HPO4
If even more energy is required the second phosphate may be removed as well to form adenosine monophosphate (AMP).
However if the organism does not require energy, a reverse reaction may occur where a phosphate group may be bonded back to the ADP by condensation (removal of a water molecule), using energy supplied from food or sun light (depending on organism). This stores energy until it is needed when it may be easily accessed like a battery.
This is caused and controlled by an enzyme called ATPase. ATP production is regulated by end product inhibition, this means that when the concentration gets to high because not enough is being produced, the ATP itself acts as an allosteric inhibitor. Until the concentration falls (ATP is being used at a higher rate than production) and the energy release carries on as before.
This energy may be used in muscle contraction using the protein actin and mysin, protein syntheses and also active transport (diffusion against the concentration gradient).
Atp may also be obtained by other means such as photosynthesis, but only in small amounts. Also using other molecules of food such as fats and carbohydrates, as shown below:
The energy released when cells break down molecules of fat and carbohydrates is used to create an excess of protons on one side of a membrane. Using ATP synthesis, cells use this proton imbalance to power the synthesis of ATP. In Boyer's model, the key to this process is a tiny shaft, which runs through the middle of a barrel bit of the enzyme. A flow of protons through the membrane makes the shaft spin, which sucks in the raw materials and blows out the ATP.
The production of ATP is the reason why phosphates are so important to living organisms and why it must be available. For example fertilisers must contain high levels of phosphorous to make the plant grow healthier and faster, because it may produce as much ATP as it requires
Atp (adenosine triphosphate) is required in all living cells as a continual supply of energy, to be used in processes, which keep the organism alive. ATP is a mononucleotide molecule made of three main components, the base (adenine), a phosphate chain and a ribose sugar backbone.
The first step in the production of ATP and the store of energy is Glycolysis and occurs in both aerobic respiration and anaerobic respiration. In both cases Glycolysis takes place in the cytoplasm of the cell, mostly because glucose is too big to get in to the mitochondria and because even before the prokaryotic mitochondria organelle invaded the cell, this process was taking place.
The process starts with glucose (a six carbon sugar) and two ATP molecules needed to kick-start the process by transferring glucose in to Fructose Bisphoshate another six-carbon sugar. The breaking of the Fructose Bisphoshate into two three carbon sugars called Pyruvate produces two ATP molecules per Pyruvate by the condensation reaction of a phosphate group (phosphorolation occurs) and a ADP (adenosine diphosphate). The excess hydrogen ions are removed by the aid of NAD to form one molecule of reduced NAD per pyruvate.
If the organism is anaerobic or when the supply of oxygen is not high enough for the energy consumption taking place, the NAD supply must be replenished, this involves oxidising the NAD and transferring the hydrogen to another molecule. This may be done in two ways, Lactose fermentation (producing Lactic acid) or alcoholic fermentation (producing Ethanol). Neither of these produces anymore ATP, meaning the gross product (as four are made but two ATP molecules must be used to start the process) of anaerobic respiration is only two ATP.
Mammals who need to respire anaerobically produce lactic acid. This process occurs by the three carbonic sugar Pyruvate being reduced into Lactic acid by the addition of the hydrogen ion from reduced NAD. One molecule of lactic acid is made for every pyruvate and there are two pyruvates per glucose put in. This build up of acid in the muscles causes a fall in pH, which in turn causes cramps and pains to occur. The lactic acid may be removed quickly when oxygen levels are restored.
This makes the over all reaction:
Yeast who need to respire anaerobically produce ethanol. This process occurs the same way except Ethanol (two carbon back bone) is produced and carbon dioxide is given off as another waste product.
This makes the equation:
However if the organism is not anaerobic then further processes may take place and produce more ATP molecules (about another 34 - 36 molecules, as two already produced). These processes take place in the mitochondria but the pyruvate molecule is too big so must again be broken down into acetylcoenzyme (Acetyl CoA) (a two carbon molecule). This “Link” reaction is catalysed by the enzyme CoA. The extra hydrogen is reduced on to NAD to form, reduced NAD. The extra carbon and two oxygen atoms are removed (oxidative decarboxylation) to form carbon dioxide, which is exhaled through the lungs and removed from the body. The molecule is now small enough to travel through the membrane into the matrix, where Krebs cycle takes place.
At the Krebs cycle the CoA enzyme enters the Acetyl into the Krebs cycle, then returns to the cytoplasm to transport another Acetyl. Each time the cycle is completed one ATP molecule is produced by substrate level phosphorolation (see below for more details)
The Last process takes place on the Christi of the mitochondria and is called the Electron Transport Chain. This is the most efficient stage of respiration where around thirty-two molecules of ATP may be produced via a series of redox (oxidation and reduction reactions) reactions. (See diagram below) – The hydrogen ions are brought by the reduced NAD and reduced FAD; this replenishes the cells supply of hydrogen carriers. The hydrogen atoms are brought at different energy levels depending on the carrier (NAD at the higher energy level). Once these hydrogen ions (+) are on the electron transport chain they moved along the chain, this happens because each successive carrier on the chain has a higher electro negativity than the carrier one before it, therefore the positive hydrogen ions are pulled along down the chain. While there are being pulled along they participate in a series of redox reactions, which join the free phosphorous groups to ADP molecules to form the end ATP.
At the last electron carrier, the cytochrome oxidase oxygen is used to get rid of the left over hydrogen ions (+), by joining together to form water as they are acidic and a build up would cause problems. This is why when a person is suffocated respiration must stop.
ATP is only produced, as it is required. It releases energy by breaking off the last phosphate group on the phosphate chain, attached with a very unstable covalent bond; the bond is broken by hydrolysis (the addition of water) releasing around 30 kJ of energy (a exergonic reaction). This leaves adenosine diphosphate (ADP), while the phosphate group usually joins with a hydrogen atom to form orthophosphate (HPO4).
ATP + H2O ADP + HPO4
If even more energy is required the second phosphate may be removed as well to form adenosine monophosphate (AMP).
However if the organism does not require energy, a reverse reaction may occur where a phosphate group may be bonded back to the ADP by condensation (removal of a water molecule), using energy supplied from food or sun light (depending on organism). This stores energy until it is needed when it may be easily accessed like a battery.
This is caused and controlled by an enzyme called ATPase. ATP production is regulated by end product inhibition, this means that when the concentration gets to high because not enough is being produced, the ATP itself acts as an allosteric inhibitor. Until the concentration falls (ATP is being used at a higher rate than production) and the energy release carries on as before.
This energy may be used in muscle contraction using the protein actin and mysin, protein syntheses and also active transport (diffusion against the concentration gradient).
Atp may also be obtained by other means such as photosynthesis, but only in small amounts. Also using other molecules of food such as fats and carbohydrates, as shown below:
The energy released when cells break down molecules of fat and carbohydrates is used to create an excess of protons on one side of a membrane. Using ATP synthesis, cells use this proton imbalance to power the synthesis of ATP. In Boyer's model, the key to this process is a tiny shaft, which runs through the middle of a barrel bit of the enzyme. A flow of protons through the membrane makes the shaft spin, which sucks in the raw materials and blows out the ATP.
The production of ATP is the reason why phosphates are so important to living organisms and why it must be available. For example fertilisers must contain high levels of phosphorous to make the plant grow healthier and faster, because it may produce as much ATP as it requires
