Mitochondria Flashcards
(22 cards)
Where does electron transport take place?
In four large protein complexes embedded in the inner mitochondrial membrane.
Which enzymes of metabolism are contained in the mitochondria?
1) Pyruvate dehydrogenase
2) TCA enzymes
3) Fatty acid oxidation enzymes
4) Electron transport/oxidative phosphorylation enzymes
How much of eukaryotic cell volume do mitochondria take up?
20% (about 200 mitochondria per cell)
What kind of membrane does mitochondria have?
Smooth outer membrane and extensively invaginated inner membrane.
Where are electron transport and oxidative phosphorylation enzymes located?
They are bound to the inner mitochondrial membrane.
What is the space in the mitochondria that is bound by the inner membrane and is comprised of a gel-like solution containing many metabolic enzymes (and other cofactors, genetic material, etc)?
Matrix (enclosed by inner membrane)
What are the invaginated folds of mitochondria called?
Cristae
What proteins located in the outer mitochondrial membrane allow free diffusion of molecules up to 10kD?
porins
How much of the mass of the inner membrane of the mitochondria is comprised of proteins?
75%
True or false: the mitochondria is richer in proteins than the cytosol.
True
True or false: The intermembrane space of the mitochondria is richer in concentration of metabolites and ions than the cytosol.
False; porins in the outer membrane allow free diffusion of molecules up to 10 kD.
Which molecules are allowed to freely travel across the inner mitochondrial membrane? How do other molecules move back and forth?
O2, CO2, H2O; all other molecules require transport proteins
How do ATP, ADP, pyruvate, Ca2+, and phosphate get across the inner mitochondrial membrane?
Via transport proteins
What results in the compartmentalization of metabolic functions between the cytosol and the inner mitochondria?
Controlled permeability (creating an ion gradient) of the inner membrane
Which molecules are allowed to travel freely across the outer mitochondrial membrane?
Any up to 10 kD (via porins)
Where in the mitochondria do most of the reactions of the citric acid cycle and fatty acid oxidation take place?
Mitochondrial matrix
Where does oxidative phosphorylation take place?
Inner mitochondrial membrane
What is the significance of the cristae (folds) of the mitochondial inner membrane?
It increases the surface area of the mitochondria, creating more sites for oxidative phosphorylation.
True or false: The inner mitochondrial membrane is impermeable to almost all ions and polar molecules (they cannot simply diffuse).
True
What is the membrane potential on the cytoplasmic side of the mitochondrial inner membrane?
positive
What is the membrane potential on the matrix side of the mitochondrial inner membrane?
negative
What kind of ion gradient is created by the selective permeability of the inner mitochondrial membrane?
Proton gradient
