Concept explainers
Interpretation:
The observation that uncouplers of oxidative phosphorylation in the mitochondria also uncouple the photoelectron transport and ATP synthesis in the chloroplast is to be explained.
Concept introduction:
There are a series of
Photosynthesis occurs in the presence of light, and water is converted to oxygen by oxidation and
The
The coupling of the reaction depends on the proton gradient across the membrane in both the mitochondria and the chloroplast.
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Biochemistry
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- REFLECT AND APPLLY Show how the estimate of 33% efficiency of energy use in anaerobic glycolysis is derived.arrow_forwardREFLECT AND APPLY The malate-aspartate shuttle yields about 2.5 moles of ATP for each mole of cytosolic NADH. Why does nature use the glycerol-phosphate shuttle, which yields only about 1.5 moles of ATP?arrow_forwardREFLECT AND APPLY Explain how the pentose phosphate path- way can respond to a cells need for ATP, NADPH, and ribose-5- phosphate.arrow_forward
- REFLECT AND APPLY If photosynthesizing plants are grown in the presence of 14CO2, is every carbon atom of the glucose that is produced labeled with the radioactive carbon? Why or why not?arrow_forwardREFLECT AND APPLY In biochemistry, the exergonic process of converting glucose and oxygen to carbon dioxide and water in aerobic metabolism can be considered the reverse of photosynthesis, in which carbon dioxide and water are converted to glucose and oxygen. Do you expect both processes to be exergonic, both endergonic, or one exergonic and one endergonic? Why? Would you expect both processes to take place in the same way? Why?arrow_forwardREFLECT AND APPLY What are some of the difficulties in determining the exact number of protons pumped across the inner mitochondrial membrane by the respiratory complexes?arrow_forward
- REFLECT AND APPLY Cytochrome oxidase and succinate-CoQ oxidoreductase are isolated from mitochondria and are incubated in the presence of oxygen, along with cytochrome c, coenzyme Q, and succinate. What is the overall oxidationreduction reaction that can be expected to take place?arrow_forwardREFLECT AND APPLY Two biochemistry students are about to use mitochondria isolated from rat liver for an experiment on oxidative phosphorylation. The directions for the experiment specify addition of purified cytochrome c from any source to the reaction mixture. Why is the added cytochrome c needed? Why does the source not have to be the same as that of the mitochondria?arrow_forwardREFLECT AND APPLY The enzyme lactate dehydrogenase catalyzes the reaction Pyruvate+NADH+H+lactate+NAD+ NADH absorbs light at 340 nm in the near-ultraviolet region of the electromagnetic spectrum, but NAD1 does not. Suggest an experimental method for following the rate of this reaction, assuming that you have available a spectrophotometer capable of measuring light at this wavelength.arrow_forward
- BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage Learning