All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources
Example Questions
Example Question #1 : Help With Mitochondria Structure
What is the primary purpose of cristae in the mitochondria?
Protect the mitochondrial genome
Prevent the mitochondria from folding in on itself
Provide a large surface area for chemical reactions
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 #2 : Help With Mitochondria Structure
Where does the Krebs cycle take place in the mitochondria?
Outer mitochondrial membrane
Inner mitochondrial membrane
Intermembrane space
Mitochondrial matrix
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?
Intermembrane space
Thylakoid space
Matrix
Outer membrane
Inner membrane
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 #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?
ADP phosphatase, mitochondrial cristae
ADP phosphorylase, inner mitochondrial membrane
ATP synthase, outer mitochondrial membrane
ATP synthase, 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.
Certified Tutor
Certified Tutor