Module 2: Lesson 5 Flashcards
What is the mitochondrial matrix?
A highly concentrated mixture of enzymes, and the site of fatty acid oxidation and the citric acid cycle.
What is the mitochondrial inner membrane?
The inner membrane consists of folded cristae to increase membrane space. The membrane carries out oxidative phosphorylation. It is non-permeable and selective.
What is the mitochondrial outer membrane?
The outer membrane consists of large porins and renders the mitos permeable at less than or equal to 5 kD.
What is the mitochondrial intermembrane space?
The space between the two mitochondrial membranes is the site of the proton buildup that drives ATP synthesis. It also contains proteins released during apoptosis.
How are damaged mitochondria removed?
Mitophagy, which is the autophagy of the mitochondria.
How are damaged cells removed?
Apoptosis, initiated by the mitochondria and mediated by a release of cytochrome c.
What is cardiolipin?
A “double” phospholipid that contains four fatty acids and constitutes 20% of the total lipids in the inner mitochondrial membrane (IMM). It also promotes membrane curvature.
How is the majority of ATP generated?
In the process involving the transport of electrons, derived from NADH and FADH2, along the IMM.
What are the two linked stages of oxidative phosphorylation?
Electrons are transferred from activated carriers to oxygen and protons are pumped across the IMM to generate an electrochemical gradient; protons flow down the electrochemical gradient to synthesize ATP.
What are the essential requirements for chemiosmotic coupling in the mitochondria?
The inner mitochondrial membrane, a source of high-energy electrons (NADH, FADH2), a set of protein complexes embedded within the membrane, and protons to generate an H+ gradient.
The IMM contains…
Proteins involved in electron transport, ATP synthase, and transport proteins allowing the passage of metabolites in and out of the matrix.
What are the names of ETC Complexes I-IV?
I: NADH dehydrogenase complex; II: succinate dehydrogenase complex; III: cytochrome c reductase complex; IV: cytochrome c oxidase complex
What is ubiquinone?
A mobile electron carrier that transfers electrons from Complex I and Complex II to Complex III INSIDE the IMM. It is hydrophobic and NOT a protein.
What is the iron-sulfur center in the ETC?
Protein sulfur residues in Complex I and II that bind iron. It possesses low affinity for electrons and readily donates to ubiquinone.
What is the final electron acceptor in the ETC?
Oxygen, which forms water.
What are the major consequences of active proton pumping?
It generates a protein gradient across the IMM where the pH is lower in the IMM than in the matrix; it generates a membrane potential across the IMM.
What drives ATP synthesis?
The electrochemical proton gradient across the IMM.
What is the function of ATP synthase?
It creates a hydrophilic pathway along the IMM allowing proton flow down its electrochemical gradient, which drives the energetically unfavorable reaction of ATP to ADP. ATP synthase is also reversible.
