All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
Example Questions
Example Question #24 : Cell Biology
What is the primary purpose of cristae in the mitochondria?
Prevent the mitochondria from folding in on itself
Provide a large surface area for chemical reactions
Protect the mitochondrial genome
No purpose has yet been identified; they are likely an evolutionary remnant
Provide a large surface area for chemical reactions
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 : Mitochondria And Chloroplasts
Where does the Krebs cycle take place in the mitochondria?
Intermembrane space
Mitochondrial matrix
Outer mitochondrial membrane
Inner mitochondrial membrane
Mitochondrial matrix
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 #1 : Mitochondria And Chloroplasts
In what part of mitochondria does the electron transport chain take place?
Outer membrane
Inner membrane
Intermembrane space
Matrix
Thylakoid space
Inner membrane
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 #2 : Help With Mitochondria Structure
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?
ADP phosphatase, mitochondrial cristae
ATP synthase, outer mitochondrial membrane
ATP synthase, inner mitochondrial membrane
ADP phosphorylase, inner mitochondrial membrane
ATP reductase, mitochondrial cristae
ATP synthase, inner mitochondrial membrane
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.
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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
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