Question

Match List I with List II regarding cellular processes and their specific locations within the cell: \begin{center} \begin{tabular}{ll} List I (Process) & List II (Location)
A. Glycolysis & I. Inner mitochondrial membrane
B. ETS & II. Mitochondrial matrix
C. Accumulation of protons & III. Cytoplasm
D. Krebs' cycle & IV. Intermembrane space
\end{tabular} \end{center} Choose the correct answer from the options given below:

• A. A-IV, B-II, C-I, D-III
• B. A-I, B-IV, C-III, D-II
• C. A-II, B-III, C-IV, D-I
• D. A-III, B-I, C-IV, D-II

Hint:

Think of the Matrix as the "Inside Room" (Krebs) and the Intermembrane Space as the "Pressure Tank" (Proton accumulation) that drives the ATP turbine!

Answer 1

The Correct Option is D

Aerobic respiration is a multi-step process that is compartmentalized within the cell to maximize efficiency and maintain necessary chemical gradients. The specific locations for each stage are:
• Glycolysis (A): This occurs in the Cytoplasm (III). It is the universal first step of glucose breakdown, occurring in both aerobic and anaerobic organisms. It does not require oxygen or specialized organelles.
• Electron Transport System (B): The ETS consists of a series of protein complexes and organic molecules located in the Inner Mitochondrial Membrane (I). This is where the majority of ATP is generated through oxidative phosphorylation.
• Accumulation of Protons (C): As electrons move through the ETS, the energy released is used to pump protons ($H^{+}$) from the matrix into the Intermembrane Space (IV). This creates a high concentration of protons, forming the "proton motive force."
• Krebs' Cycle (D): Also known as the Citric Acid Cycle, this series of enzymatic reactions takes place within the Mitochondrial Matrix (II). It is here that Acetyl CoA is fully oxidized into $CO_2$. Matching these leads to: A-III, B-I, C-IV, D-II.