The electron transport chain ________.
a. Is located in the matrix of the mitochondrion.
b. Has the electronegative carbon dioxide at its base.
c. Is a series of nucleotides located in the inner mitochondrial membrane.
d. Is a series of enzymes located in the intermembrane space.
e. Moves electrons from protein to protein and moves protons from the matrix into the intermembrane space.

Verified step by step guidance

1. Understand the concept of the electron transport chain (ETC): The ETC is a series of protein complexes and other molecules embedded in the inner mitochondrial membrane. Its primary function is to transfer electrons through a chain of proteins and pump protons (H⁺ ions) across the membrane to create a proton gradient.
2. Analyze the location of the ETC: The ETC is specifically located in the inner mitochondrial membrane, not in the matrix or intermembrane space. This is a key detail to eliminate incorrect options.
3. Review the role of carbon dioxide: Carbon dioxide (CO₂) is not involved in the electron transport chain. Instead, it is a byproduct of earlier stages of cellular respiration, such as the citric acid cycle. This helps rule out options mentioning CO₂.
4. Understand the movement of electrons and protons: In the ETC, electrons are passed from one protein complex to another, and this movement drives the active transport of protons (H⁺) from the mitochondrial matrix into the intermembrane space, creating an electrochemical gradient.
5. Evaluate the options: Based on the above understanding, identify the correct description of the ETC. The correct option should describe the ETC as a series of proteins in the inner mitochondrial membrane that move electrons and pump protons into the intermembrane space.

Key Concepts

Electron Transport Chain (ETC)

The electron transport chain is a series of protein complexes and other molecules located in the inner mitochondrial membrane. It plays a crucial role in cellular respiration by transferring electrons from electron donors like NADH and FADH2 to electron acceptors, ultimately producing ATP through oxidative phosphorylation.

Proton Gradient

As electrons are transferred through the ETC, protons (H+) are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient. This gradient is essential for ATP synthesis, as protons flow back into the matrix through ATP synthase, driving the conversion of ADP to ATP.

Oxidative Phosphorylation

Oxidative phosphorylation is the process by which ATP is produced using the energy derived from the electron transport chain. It involves the coupling of electron transfer to the phosphorylation of ADP, facilitated by the proton gradient established by the ETC, making it a key component of aerobic respiration.