What role does chemiosmosis play in ATP synthesis and how is ATP synthase involved?
Finally, we're down to the last step of chemiosmosis! Don't stop paying attention yet, though! This final step is essential to the production of ATP, a molecule that is virtually indispensable in all living things. After protons have been pumped out of the intramembrane space, we previously discussed the effects of the law of diffusion on the protons. As a result, we know that the H+ ions have a tendency to flow from areas of high proton concentration (outside of the membrane) to areas of low proton concentration (inside the membrane). So how do they do this? The answer is ATP synthase.
ATP synthase is an enzyme embedded within the inner mitochondrial membrane (in animal cells) and in the thylakoid membrane (in plant cells). It is a hollow shape with a pathway in its center that enables protons to flow across the membrane into the mitochondrial matrix or thylakoid lumen. As protons move across the membrane as facilitated by ATP synthase, energy is produced. This energy is used to catalyze the formation of ATP by ATP synthase (hence its namesake) through the following reaction:
ADP (adenosine diphosphate) + Pi (inorganic phosphate) ---> ATP (adenosine triphosphate)
Therefore, the movement of protons powers the accelerated ATP production reaction. Through the flow of H+ ions through ATP synthase, a total of 36 ATP are generated through the Krebs cycle and chemiosmosis (actually, 38 ATP are produced in total after taking the 2 ATP formed through glycolysis into account). This extraordinarily higher number of ATP produced through aerobic means gives eukaryotes a significant advantage over prokaryotes (such as bacteria) because each eukaryote receives more ATP (36 ATP through aerobic processes like the Krebs cycle and chemiosmosis and 2 ATP through the anaerobic process of glycolysis) while anaerobic organisms receive far less (2 ATP through glycolysis alone). With more energy to spare, eukaryotes can carry out more complicated cellular, molecular, chemical, and mechanical processes.
ATP synthase is an enzyme embedded within the inner mitochondrial membrane (in animal cells) and in the thylakoid membrane (in plant cells). It is a hollow shape with a pathway in its center that enables protons to flow across the membrane into the mitochondrial matrix or thylakoid lumen. As protons move across the membrane as facilitated by ATP synthase, energy is produced. This energy is used to catalyze the formation of ATP by ATP synthase (hence its namesake) through the following reaction:
ADP (adenosine diphosphate) + Pi (inorganic phosphate) ---> ATP (adenosine triphosphate)
Therefore, the movement of protons powers the accelerated ATP production reaction. Through the flow of H+ ions through ATP synthase, a total of 36 ATP are generated through the Krebs cycle and chemiosmosis (actually, 38 ATP are produced in total after taking the 2 ATP formed through glycolysis into account). This extraordinarily higher number of ATP produced through aerobic means gives eukaryotes a significant advantage over prokaryotes (such as bacteria) because each eukaryote receives more ATP (36 ATP through aerobic processes like the Krebs cycle and chemiosmosis and 2 ATP through the anaerobic process of glycolysis) while anaerobic organisms receive far less (2 ATP through glycolysis alone). With more energy to spare, eukaryotes can carry out more complicated cellular, molecular, chemical, and mechanical processes.
So
For an overview of chemiosmosis and ATP synthase, watch the video below!
Need a detailed review on everything we've discussed thus far and more? Check out this video by an AP Biology student for AP Biology students!