GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Help with Mitochondria Structure

Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology

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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

1 Diagnostic Test 201 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #25 : Cell Biology

What is the primary purpose of cristae in the mitochondria?

Possible Answers:

No purpose has yet been identified; they are likely an evolutionary remnant 

Provide a large surface area for chemical reactions

Protect the mitochondrial genome

Prevent the mitochondria from folding in on itself

Correct answer:

Provide a large surface area for chemical reactions

Explanation:

The importance of the cristae comes from the fact that they greatly increase the surface area of the inner membrane of the mitochondria. This is important because this membrane houses the electron transport chain proteins. A larger surface area allows reactions to occur at a higher rate and, thus, more ATP can be generated. The cristae are not essential to protecting the mitochondrial genome or maintaining shape.

Example Question #1 : Help With Mitochondria Structure

Where does the Krebs cycle take place in the mitochondria?

Possible Answers:

Mitochondrial matrix

Intermembrane space

Outer mitochondrial membrane

Inner mitochondrial membrane

Correct answer:

Mitochondrial matrix

Explanation:

The mitochondrion is a double-membraned organelle responsible for generating ATP for the cell. The Krebs cycle is the middle step of cellular respiration, and takes place in the mitochondrial matrix.

Example Question #2 : Help With Mitochondria Structure

In what part of mitochondria does the electron transport chain take place?

Possible Answers:

Intermembrane space

Matrix

Inner membrane 

Thylakoid space

Outer membrane 

Correct answer:

Inner membrane 

Explanation:

While the matrix, outer membrane, and intermembrane spaces are components of mitochondria, the correct answer is inner membrane. The thylakoid space is found in chloroplasts not mitochondria. Compounds are embedded in the inner membrane and transfer electrons from electron donors to electron acceptors by redox reactions. The final enzyme in the chain is ATP synthase, which generates ATP from ADP and inorganic phosphate. 

Example Question #1 : Mitochondria And Chloroplasts

Crucial steps of the citric acid cycle and the electron transport chain occur within the mitochondria. Which of the following pairs of answers contains an enzyme essential to ATP synthesis, and its correct mitochondrial localization?

Possible Answers:

ADP phosphorylase, inner mitochondrial membrane

ATP synthase, outer mitochondrial membrane

ATP synthase, inner mitochondrial membrane

ADP phosphatase, mitochondrial cristae

ATP reductase, mitochondrial cristae

Correct answer:

ATP synthase, inner mitochondrial membrane

Explanation:

ATP synthase is the correct enzyme, and it is powered by a  gradient that permits the addition of an inorganic phosphate group to a molecule of ADP. This is located in the inner membrane of the mitochondria, where the ETC is pumping  out to form the necessary gradient required to power ATP synthase. 

All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

1 Diagnostic Test 201 Practice Tests Question of the Day Flashcards Learn by Concept
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