Question

Which of these statements is incorrect?

• A. Glycolysis occurs in cytosol
• B. Glycolysis operates as long as it is supplied with NAD+ that can pick up hydrogen atoms
• C. Oxidative phosphorylation occurs in the outer mitochondrial matrix
• D. Enzymes of TCA cycle are present in mitochondrial matrix

Answer 1

The correct option is C

Oxidative phosphorylation occurs in the outer mitochondrial matrix

The correct option is C.

Explanation for the correct option:

Statement (iii):

1. In oxidative phosphorylation, energy is harnessed by a sequence of protein complexes anchored in mitochondria's inner membrane (called the electron transport chain and ATP synthase).
2. The process of oxidative phosphorylation occurs in the oxysome found in the inner membrane of mitochondria.

Explanation for the incorrect option:

Statement (i):

1. Glycolysis takes place in the cell's cytosol (the fluid that surrounds the organelles).
2. The citric acid cycle, the next phase in cellular respiration, takes place in the mitochondria.

Statement (ii):

1. Glycolysis works as long as there is NAD available to soak up hydrogen atoms produced during the oxidation of PGAL.
2. TCA cycle enzymes can be found in the mitochondrial matrix space.
3. During oxidative phosphorylation, the inner mitochondrial membrane is used.
   

Statement (iv):

1. All TCA cycle enzymes are found in the mitochondrial matrix, with the exception of one, which is found in the inner mitochondrial membranes of eukaryotes and the cytosol of prokaryotes.
   

Final answer: Oxidative phosphorylation that occurs in the outer mitochondrial matrix is the incorrect statement.