All Biochemistry Resources
Example Questions
Example Question #151 : Catabolic Pathways And Metabolism
Where does oxidative phosphorylation take place in a eukaryote?
Endoplasmic reticulum
Mitochondria
Nucleus
Cytoplasm
Lysosome
Mitochondria
Oxidative phosphorylation takes place in the mitochondria in a eukaryote. The process is made possible by the double membrane within the mitochondria.
Example Question #11 : Electron Transport Chain Proteins And Complexes
How many protons in total are pumped into the intermembrane space of a mitochondria through the electron transport chain, if each complex individually receives 2 electrons?
12 protons
8 protons
10 protons
14 protons
6 protons
12 protons
Complex I pumps 4 protons, complex IV pumps 4 protons, and the interaction between complex III and complex II is more complicated.
Complex II pumps no electrons in itself, but releases the fully reduced quinone species, , which interacts with complex III through the Q cycle. Simplified, the net result of the Q cycle is that 4 protons are pumped out into the intermembrane space. complex III pumps 2 protons from the mitochondrial matrix and 2 protons from .
This is a simplification of the 4 complexes, providing only the information necessary to complete the question. But a full understanding of the 4 complexes, and the flow of electrons is nonetheless essential for understanding why each complex pumps the number of protons it does.
Example Question #12 : Electron Transport Chain Proteins And Complexes
Which of the electron transport chain protein complexes accepts electrons from ?
Complex 2 (succinate dehydrogenase)
All of the protein complexes accept electrons from
Complex 1 (NADH-Q reductase complex)
Complex 4 (cytochrome C oxidase complex)
Complex 3 (Cytochrome C reductase complex)
Complex 2 (succinate dehydrogenase)
first delivers its electrons to complex 2 of the electron transport chain. Subsequently, the electrons are delivered to ubiquinone, and then they move through complex 3, cytochrome C, and complex 4. Complex 2, therefore, is the only protein complex that directly accepts electrons from .
Example Question #13 : Electron Transport Chain Proteins And Complexes
Which of the following is a unique property of complex 4 in the electron transport chain with respect to the other protein complexes?
It reduces oxygen to water
It is the only complex that contains iron
It accepts electrons from
It is the smallest of the protein complexes
It is the only complex that does not pump hydrogens
It reduces oxygen to water
The fourth complex in the electron transport chain is unique in that it has the important responsibility of reducing molecular oxygen to water. Oxygen is the final electron acceptor for cellular respiration, so this is a very important role. Complex 2 is the only one that accepts electrons from and is the smallest of the protein complexes. Complex 2 is also the one that does not have hydrogen pumping ability. Iron is a component of complexes 1, 3, and 4.
Certified Tutor