Oxidative Phosphorylation and Photophosphorylation
50 questions available
Questions
According to the chemiosmotic theory as proposed by Peter Mitchell, what is considered the reservoir for energy extracted from biological oxidation reactions in mitochondria and chloroplasts?
View answer and explanationWhich component of the mitochondrial respiratory chain is described as a lipid-soluble benzoquinone with a long isoprenoid side chain, capable of shuttling reducing equivalents between less mobile electron carriers?
View answer and explanationWhat is the function of Complex IV, also known as cytochrome oxidase, in the mitochondrial respiratory chain?
View answer and explanationFor each pair of electrons transferred from NADH through the respiratory chain to oxygen, how many protons are pumped out of the matrix by Complex I, Complex III, and Complex IV respectively?
View answer and explanationWhat is the standard free-energy change (DG'°) for the transfer of a pair of electrons from NADH to O2, given that the standard reduction potential (E'°) for the NAD+/NADH pair is -0.320 V and for the O2/H2O pair is 0.816 V?
View answer and explanationThe binding-change model for ATP synthase proposed by Paul Boyer describes a rotational catalysis mechanism. What is the direct driver of the conformational changes in the beta subunits of the F1 complex?
View answer and explanationWhat is the function of thermogenin, also known as uncoupling protein 1 (UCP1), found in the mitochondria of brown adipose tissue?
View answer and explanationWhat is the role of cytochrome c in the process of apoptosis?
View answer and explanationAccording to the endosymbiotic hypothesis, how did primitive eukaryotes acquire the ability to carry out oxidative phosphorylation?
View answer and explanationWhat is the key distinction between the light-dependent reactions and the carbon-assimilation reactions in photosynthesis?
View answer and explanationWhat is the energy, in kilojoules per einstein, of photons with a wavelength of 700 nanometers, as calculated in the worked example?
View answer and explanationIn the photochemical reaction center of purple bacteria, what is the 'special pair' designated (Chl)2 that is the site of the initial photochemistry?
View answer and explanationIn the Z scheme of photosynthesis in plants, what is the role of Photosystem II (PSII)?
View answer and explanationWhat is the function of the oxygen-evolving complex, also known as the water-splitting complex, in photosynthesis?
View answer and explanationHow many protons are moved from the stroma to the thylakoid lumen for every four electrons passed from water to NADP+ in plant chloroplasts?
View answer and explanationThe inhibitor IF1 prevents ATP hydrolysis during hypoxia. Under what condition is IF1 inhibitory?
View answer and explanationWhich genetic disease is caused by a mutation in a mitochondrial gene for a subunit of Complex I, leading to bilateral loss of vision in early adulthood?
View answer and explanationWhat is the primary function of accessory pigments like carotenoids in photosynthesis?
View answer and explanationHow many protons must flow inward through the F-type ATPase in yeast mitochondria to drive the synthesis of one molecule of ATP, including the transport of substrates?
View answer and explanationWhat is the primary function of the glycerol 3-phosphate shuttle, which is active in skeletal muscle and brain?
View answer and explanationWhat is the immediate electron donor that replaces the electron lost from P700 in Photosystem I after photoexcitation?
View answer and explanationWhat is the key difference in the products of noncyclic versus cyclic electron flow in photophosphorylation?
View answer and explanationWhat is the function of the enzyme superoxide dismutase in cells?
View answer and explanationHow many subunits of Complex IV (cytochrome oxidase) in the human mitochondrial respiratory chain are encoded by mitochondrial DNA?
View answer and explanationIn the Hill reaction, what did Robert Hill's experiments demonstrate about photosynthesis in isolated chloroplasts?
View answer and explanationWhat is the primary role of the hypoxia-inducible factor (HIF-1)?
View answer and explanationOn the basis of the binding-change model, what are the three successive conformations that each catalytic beta subunit of ATP synthase cycles through?
View answer and explanationWhat is the P/O ratio, defined as the ratio of ATP synthesized per 1/2 O2 reduced, when electrons enter the respiratory chain from succinate?
View answer and explanationWhat is the effect of the drug rotenone on mitochondrial respiration?
View answer and explanationIn the process of state transitions in chloroplasts, what triggers the phosphorylation of LHCII and its move from association with PSII to PSI?
View answer and explanationWhat is the primary function of the cytochrome P-450 enzymes located in the endoplasmic reticulum of hepatocytes?
View answer and explanationIn the absence of a proton gradient, what is the key observation about the reaction ADP + Pi <-> ATP + H2O on the surface of the F1 component of ATP synthase?
View answer and explanationHeteroplasmy in mitochondrial genetics refers to which condition?
View answer and explanationWhat is the role of the Pi-triose phosphate antiporter in the inner chloroplast membrane?
View answer and explanationWhat is the total number of subunits in the F1 portion of mitochondrial ATP synthase?
View answer and explanationWhich of the following agents acts as an uncoupler of oxidative phosphorylation by functioning as a K+ ionophore?
View answer and explanationWhat is the primary role of bacteriorhodopsin in Halobacterium salinarum?
View answer and explanationHow is the regulation of Complex IV in mitochondria adapted for hypoxic conditions?
View answer and explanationWhat is the estimated free-energy change for moving one mole of protons down the electrochemical gradient in actively respiring mitochondria, given a measured change in electrical potential of 0.15 V and a pH difference of 0.75 units?
View answer and explanationIn the context of photorespiration, what is the oxygenase activity of rubisco?
View answer and explanationWhich of these complexes is NOT involved in the cyclic electron flow pathway in plant chloroplasts?
View answer and explanationWhat is the primary factor that regulates the partitioning of glucose 6-phosphate between glycolysis and the pentose phosphate pathway in plants?
View answer and explanationWhat is the role of the adenine nucleotide translocase in mitochondrial function?
View answer and explanationHow does the uncoupler 2,4-dinitrophenol (DNP) disrupt the tight coupling between electron transfer and ATP synthesis?
View answer and explanationWhat is the predicted ATP yield per pair of electrons from FADH2 if the mitochondrial ATP synthase has 10 c subunits, as in yeast?
View answer and explanationHow many protein subunits does the enzyme Complex II (succinate dehydrogenase) contain?
View answer and explanationWhich class of cytochromes contains a heme group that is covalently attached to the protein through thioether bonds to two Cys residues?
View answer and explanationWhat is the acceptor control of respiration?
View answer and explanationIn the Rieske iron-sulfur proteins, what is the unique feature of the iron atom's coordination?
View answer and explanationWhat is the function of the enzyme ferredoxin:NADP+ oxidoreductase in plant photosynthesis?
View answer and explanation