HW 9.4
What types of cells carry out ATP synthesis by chemiosmosis?
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
Which of the following molecules is the lowest-energy donor of electrons to the electron transport chain?
FADH2
Which of the following statements best describes the primary role played by oxygen in cellular respiration?
It serves as the final acceptor for electrons from the electron transport chain
If a cell produces on average 30 ATP molecules for each molecule of glucose that is completely oxidized to carbon dioxide and water, how many ATP molecules on average can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?
12.5
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?
30-32
In chemiosmosis, the most direct source of energy used to convert ADP + Pi to ATP is energy released ________.
from movement of protons through ATP synthase, down their electrochemical gradient
Inhibition of which of the following processes would reduce or eliminate generation of a proton-motive force in mitochondria?
pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space
Which of the following events takes place in the electron transport chain?
the harnessing of energy from redox reactions to generate a proton gradient
Which of the following statements best describes the electron transport chain?
It consists of a series of redox reactions.
Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal to form small vesicles that contain the intermembrane space. These vesicles can transfer electrons from NADH to oxygen and synthesize ATP. Which of the following statements best describes what will happen to the vesicles when NADH is added?
The inside of the vesicles will become acidic
Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal "inside out" to form small vesicles. The fact that these vesicles can transfer electrons from NADH to oxygen and synthesize ATP suggests that which of the following components must be present?
all of the electron transport system and ATP synthase
The synthesis of ATP by oxidative phosphorylation is an example of which of the following processes?
coupling of an endergonic reaction to an exergonic reaction
Which of the following sequences describes the path by which electrons move from high-energy to lower-energy molecules in aerobic respiration?
glucose →→ NADH →→ electron transport chain →→ oxygen
If the proteins of the electron transport chain were labeled with a fluorescent tag, the fluorescence observed by microscopy will be localized to which of the following regions of the mitochondria?
inner membrane
Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic cells?
mitochondrial intermembrane space
Assume that it is possible to label each of the molecules below with 18O a heavy isotope of oxygen. As a result of cellular respiration, water containing 18O would most quickly be detected if cells are provided with which one of the following molecules labeled with 18O?
molecular oxygen (O2)
In liver cells, the inner mitochondrial membranes contain about five times the surface area of the outer mitochondrial membranes, which allows for increased rates of which process below?
oxidative phosphorylation
Which of the following processes is driven by chemiosmosis?
oxidative phosphorylation
A person on a strict diet and exercise regimen lost 7 kg (about 15 pounds) of body fat in just two weeks. In which of the following forms did the lost fat most likely leave the body?
released as CO2 and H2O
When a cell is deprived of oxygen, which of the following processes will be inhibited first?
the electron transport chain