Question

Oxidative phosphorylation occurs in the __________.

• A. cytoplasm
• B. chloroplast
• C. mitochondria
• D. nucleus

Answer 1

The correct option is C mitochondria

Oxidative phosphorylation occurs in mitochondria. It takes place in the inner mitochondrial membrane. The inner mitochondrial membrane has four complexes that accept and transfer electrons released from $NADH+H^{+}$ and $FAD{H}_2$. As the electrons move through different complexes they release energy. This energy is utilized to pump protons from the matrix to the intermembrane space. The protons accumulate in the intermembrane space and create a proton gradient. Later the protons move through the complex V (ATP synthase) into the matrix from intermembrane space.

Complex V has two components, $F_0$ and $F_1$. $F_0$ forms the channel for the passage of protons and $F_1$ has a site for the synthesis of ATP from ADP and inorganic phosphate.

The first step of cellular respiration i.e., glycolysis takes place in the cytoplasm.

Chloroplast is the cell organelle in plants where photosynthesis takes place.

Nucleus controls and coordinates the various activities of the cell.