CELLULAR RESPIRATION
Cellular respiration is the process by which the chemical energy of "food" molecules is released and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved.
GLYCOLYSIS
This process occurs in the cytoplasm irrsepective of the presence or absence of oxygen.In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.
KREB CYCLE
The Krebs cycle occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis.Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule. When acetyl-CoA is oxidized to carbon dioxide in the Krebs cycle, chemical energy is released and captured in the form of NADH, FADH2, and ATP.
OXIDATIVE PHOSPHORYLATION VIA THE ELECTRON TRANSPORT CHAIN
The electron transport chain allows the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2). The energy released is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH2).
NADH + H+ + 3 ADP + 3 Pi + 1/2 O2 ---> NAD+ + H2O + 3 ATP
FADH2 + 2 ADP + 2 Pi + 1/2 O2 ---> FAD+ + H2O + 2 ATP
The electron transport chain (ETC) consists of a series of molecules, mostly proteins, embedded in the inner mitochondrial membrane.
HOW RESPIRATION MAKES ENERGY
Respiration is the release of energy from glucose or other organic substances. Energy is required for growth, repair, movement and other metabolic activities.
There are two main types of respiration -
1) Aerobic respiration
2) Anaerobic respiration
AEROBIC RESPIRATION
It takes place in the presence of oxygen.Glucose molecules react with oxygen molecules to form carbon dioxide and water molecules, with energy being released by the breaking of bonds in the glucose molecules.The energy released from glucose in respiration is used to produce a chemical called adenosine triphosphate (ATP). ATP is where the energy released during respiration is stored for future use.
Glucose + Oxygen ---> Carbon Dioxide + Water + Energy
A lot of energy is released in aerobic respiration - 2900 kj from one glucose and 6 oxygen molecules.
ANAEROBIC RESPIRATION
It occurs when oxygen is not available. In anaerobic respiration the glucose is only partially broken down, and lactic acid is produced - together with a much smaller amount of energy.
Glucose ---> lactic acid + carbon dioxide + energy
This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.
One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.
When anaerobic respiration occurs in yeast it is called fermentation. In this case ethanol (alcohol) is produced instead of lactic acid, and this reaction is used in the brewing of alcoholic drinks.
Glucose ---> ethanol + carbon dioxide + energy
All cells are able to synthesize ATP via the process of glycolysis. In many cells, if oxygen is not present, pyruvate is metabolized in a process called fermentation.Fermentation complements glycolysis and makes it possible for ATP to be continually produced in the absence of oxygen. By oxidizing the NADH produced in glycolysis, fermentation regenerates NAD+, which can take part in glycolysis once again to produce more ATP.
During vigorous exercise the body needs a lot more energy. It gets this by breathing in deeper and faster and rushing the oxygen to the muscles in dilated blood vessels. This extra oxygen is then used to release more energy, needed to meet the higher level of demand. Soon a point is reached when the body cannot breathe any faster or harder, and aerobic respiration alone cannot meet the enhanced energy demands. So how do muscle cells get the extra energy they need? They get it by respiring anaerobically.
But anaerobic respiration produces lactic acid, which accumulates in the muscles and causes muscle fatigue and cramps. To avoid damage to cells, lactic acid has to be broken down to carbon dioxide and water immediately the exercise has finished. This is an oxidisation reaction, and requires oxygen.
This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.
One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.
Cellular respiration is the process by which the chemical energy of "food" molecules is released and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved.
GLYCOLYSIS
This process occurs in the cytoplasm irrsepective of the presence or absence of oxygen.In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.
KREB CYCLE
The Krebs cycle occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis.Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule. When acetyl-CoA is oxidized to carbon dioxide in the Krebs cycle, chemical energy is released and captured in the form of NADH, FADH2, and ATP.
OXIDATIVE PHOSPHORYLATION VIA THE ELECTRON TRANSPORT CHAIN
The electron transport chain allows the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2). The energy released is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH2).
NADH + H+ + 3 ADP + 3 Pi + 1/2 O2 ---> NAD+ + H2O + 3 ATP
FADH2 + 2 ADP + 2 Pi + 1/2 O2 ---> FAD+ + H2O + 2 ATP
The electron transport chain (ETC) consists of a series of molecules, mostly proteins, embedded in the inner mitochondrial membrane.
HOW RESPIRATION MAKES ENERGY
Respiration is the release of energy from glucose or other organic substances. Energy is required for growth, repair, movement and other metabolic activities.
There are two main types of respiration -
1) Aerobic respiration
2) Anaerobic respiration
AEROBIC RESPIRATION
It takes place in the presence of oxygen.Glucose molecules react with oxygen molecules to form carbon dioxide and water molecules, with energy being released by the breaking of bonds in the glucose molecules.The energy released from glucose in respiration is used to produce a chemical called adenosine triphosphate (ATP). ATP is where the energy released during respiration is stored for future use.
Glucose + Oxygen ---> Carbon Dioxide + Water + Energy
A lot of energy is released in aerobic respiration - 2900 kj from one glucose and 6 oxygen molecules.
ANAEROBIC RESPIRATION
It occurs when oxygen is not available. In anaerobic respiration the glucose is only partially broken down, and lactic acid is produced - together with a much smaller amount of energy.
Glucose ---> lactic acid + carbon dioxide + energy
This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.
One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.
When anaerobic respiration occurs in yeast it is called fermentation. In this case ethanol (alcohol) is produced instead of lactic acid, and this reaction is used in the brewing of alcoholic drinks.
Glucose ---> ethanol + carbon dioxide + energy
All cells are able to synthesize ATP via the process of glycolysis. In many cells, if oxygen is not present, pyruvate is metabolized in a process called fermentation.Fermentation complements glycolysis and makes it possible for ATP to be continually produced in the absence of oxygen. By oxidizing the NADH produced in glycolysis, fermentation regenerates NAD+, which can take part in glycolysis once again to produce more ATP.
During vigorous exercise the body needs a lot more energy. It gets this by breathing in deeper and faster and rushing the oxygen to the muscles in dilated blood vessels. This extra oxygen is then used to release more energy, needed to meet the higher level of demand. Soon a point is reached when the body cannot breathe any faster or harder, and aerobic respiration alone cannot meet the enhanced energy demands. So how do muscle cells get the extra energy they need? They get it by respiring anaerobically.
But anaerobic respiration produces lactic acid, which accumulates in the muscles and causes muscle fatigue and cramps. To avoid damage to cells, lactic acid has to be broken down to carbon dioxide and water immediately the exercise has finished. This is an oxidisation reaction, and requires oxygen.
This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.
One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.
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