In mitochondria, ATP synthesizing chemical reactions take place in the
- A.Outer membrane.
- B.Matrix.
- C.Inner membrane.
- D.DNA of mitochondria.
Correct answer
Explanation
The correct answer is C, Inner membrane. The enzyme that makes most of the cell's ATP, ATP synthase, sits in the inner mitochondrial membrane along with the electron transport chain.
The inner membrane is folded into cristae, which give it a large surface. The electron transport chain on it pumps hydrogen ions into the space between the two membranes. As these ions flow back through ATP synthase, the F₀–F₁ particles, the enzyme joins ADP and phosphate to make ATP. This is oxidative phosphorylation, which yields most of the roughly 30–38 ATP from one glucose molecule.
A is wrong because the outer membrane is a smooth, porous covering and carries no ATP synthase.
B is wrong because the matrix runs the Krebs cycle, which feeds electrons to the chain but makes only a little ATP directly.
D is wrong because mitochondrial DNA carries genes for some proteins; it does not itself make ATP.
Exam tip: glycolysis – cytoplasm; Krebs cycle – matrix; electron transport and ATP synthase – inner membrane (cristae).
Practice Questions
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- A.Golgi apparatus
- B.Mitochondrion
- C.Lysosome
- D.Endoplasmic reticulum
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- B.Onion, garlic, carrot
- C.Potato, onion, garlic
- D.Potato, garlic, turnip
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- A.0.5 s
- B.1 s
- C.1.5 s
- D.2 s
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- A.equal to its weight.
- B.less than its weight.
- C.greater than its weight.
- D.zero.
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- A.Forefront brain, Standard brain and Hind brain
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- C.Fore brain, Mid brain and Hind brain
- D.Precursor brain, Mean brain and Hind brain
Show answer
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