Lecture 10- Chemiosmosis Flashcards
How many protons are sent into the intermembrane space for every NADH molecule that is oxidized? How does this compare to FADH2?
3 protons. For FADH2, its electron only enters the electron transport chain later, and so it only powers the sending of 2 protons to the intermembrane space.
Through which protein do the protons reenter the mitochondrial matrix once a concentration gradient has been achieved? How does it work?
ATP synthase. For every 3 protons which pass through it, the enzyme synthesizes one molecule of ATP by turning on itself.
What is chemiosmosis?
The process by which using the proton gradient, an inorganic phosphate is attached to an ADP molecule to make ATP.
What is known as oxidative phosphorylation?
The combined processes of the electron transport chain and chemiosmosis.
What happens to the protons when they reenter the mitochondrial matrix?
Four protons (H+) bind to 4 used-up (low-energy) electrons from the electron transport chain making 4 H, which then bind to 2 O molecules (1 O2) to make 2 H2O. This is where the Oxygen is used, and why the process is called aerobic respiration.
Summarize oxidative phosphorylation.
When the NADH and FADH2 molecules attained from glycolysis, pyruvate dehydrogenase, and the krebs cycle arrive near the mitochondrial inner membrane, first the NADH, then the FADH2 have their protons and electrons removed. High energy electrons are passed around by proteins which use the energy from the electrons donated by the high energy electron carriers to create a concentration gradient of H+ inside the intermembrane space. When these H+ molecules reenter the matrix through the ATP synthase, ATP molecules are synthesized and water is created from the H+ molecules, the now low-energy electrons, and the O2 that is present.
How many ATP molecules are created for each NADH and each FADH2 molecules? What is the net yield of ATP in cellular respiration?
Each NADH gives approximately 2.5 ATP, while each FADH2 approximately 1.5 ATP. The total net yield of cellular respiration in eukaryotes is 30 ATP, 32 in bacteria.
