LABORATORY REVIEW
CELL RESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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H+ ions serve as the final electron acceptor
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a concentration gradient is generated when H+ ions are passively transported from the matrix to the intermembrane space of the mitochondrion
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energy is released as H+ ions move freely across the mitochondrial membrane
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ATP is synthesized when H+ ions move through a channel in ATP synthase
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Detailed explanation-1: -The proton gradient produced by proton pumping during the electron transport chain is used to synthesize ATP. Protons flow down their concentration gradient into the matrix through the membrane protein ATP synthase, causing it to spin (like a water wheel) and catalyze conversion of ADP to ATP.
Detailed explanation-2: -Hydrogen ions in the matrix space can only pass through the inner mitochondrial membrane through a membrane protein called ATP synthase. As protons move through ATP synthase, ADP is turned into ATP. The production of ATP using the process of chemiosmosis in mitochondria is called oxidative phosphorylation.
Detailed explanation-3: -ATP is synthesized by the enzyme F1F0-ATP synthase. This enzyme, the smallest-known molecular machine, couples proton translocation through its membrane-embedded, hydrophobic domain, F0, to the synthesis of ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi) in its soluble, hydrophilic headpiece, F1.
Detailed explanation-4: -Similarly, hydrogen ions in the matrix space can only pass through the inner mitochondrial membrane through an integral membrane protein called ATP synthase (Figure 2). This complex protein acts as a tiny generator, turned by the force of the hydrogen ions diffusing through it, down their electrochemical gradient.
Detailed explanation-5: -ATP synthase is organized into two structurally distinct components, F0 and F1, which are linked by a slender stalk (Figure 10.11). The F0 portion spans the inner membrane and provides a channel through which protons are able to flow back from the intermembrane space to the matrix.