Chapter 4: Cell Structure and Function. Chapter 5: Membranes and Cellular Transport. Chapter 6: Cell Signaling. Chapter 7: Metabolism. Chapter 9: Photosynthesis. Chapter Cell Cycle and Division. Chapter Meiosis. Chapter Classical and Modern Genetics.
Chapter Gene Expression. Chapter Biotechnology. Chapter Viruses. Chapter Nutrition and Digestion. Chapter Nervous System. Chapter Sensory Systems. Chapter Musculoskeletal System. Chapter Endocrine System. Chapter Circulatory and Pulmonary Systems.
Chapter Osmoregulation and Excretion. Chapter Immune System. Chapter Reproduction and Development. Chapter Behavior. Chapter Ecosystems. Chapter Population and Community Ecology. Chapter Biodiversity and Conservation. Chapter Speciation and Diversity.
Chapter Natural Selection. Chapter Population Genetics. Chapter Evolutionary History. Chapter Plant Structure, Growth, and Nutrition. Chapter Plant Reproduction.
Chemistry Expert. Helmenstine holds a Ph. She has taught science courses at the high school, college, and graduate levels. Facebook Facebook Twitter Twitter. Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. An Introduction to Types of Respiration. Anabolism and Catabolism Definition and Examples. What Is Fermentation? Definition and Examples. Beyond the use of the PMF to make ATP, as discussed in this chapter, the PMF can also be used to drive other energetically unfavorable processes, including nutrient transport and flagella rotation for motility.
Figure 1. This flow of hydrogen ions across the membrane, called chemiosmosis , must occur through a channel in the membrane via a membrane-bound enzyme complex called ATP synthase Figure 1. The tendency for movement in this way is much like water accumulated on one side of a dam, moving through the dam when opened.
The turning of the parts of this molecular machine regenerates ATP from ADP and inorganic phosphate P i by oxidative phosphorylation , a second mechanism for making ATP that harvests the potential energy stored within an electrochemical gradient. The number of ATP molecules generated from the catabolism of glucose varies. For example, the number of hydrogen ions that the electron transport system complexes can pump through the membrane varies between different species of organisms.
In aerobic respiration in mitochondria, the passage of electrons from one molecule of NADH generates enough proton motive force to make three ATP molecules by oxidative phosphorylation, whereas the passage of electrons from one molecule of FADH 2 generates enough proton motive force to make only two ATP molecules.
Thus, the 10 NADH molecules made per glucose during glycolysis, the transition reaction, and the Krebs cycle carry enough energy to make 30 ATP molecules, whereas the two FADH 2 molecules made per glucose during these processes provide enough energy to make four ATP molecules. Overall, the theoretical maximum yield of ATP made during the complete aerobic respiration of glucose is 38 molecules, with four being made by substrate-level phosphorylation and 34 being made by oxidative phosphorylation Table 1.
In reality, the total ATP yield is usually less, ranging from one to 34 ATP molecules, depending on whether the cell is using aerobic respiration or anaerobic respiration; in eukaryotic cells, some energy is expended to transport intermediates from the cytoplasm into the mitochondria, affecting ATP yield.
Table 1 summarizes the theoretical maximum yields of ATP from various processes during the complete aerobic respiration of one glucose molecule. Skip to main content. Microbial Metabolism. Search for:. Cellular Respiration Learning Objectives Compare and contrast the electron transport system location and function in a prokaryotic cell and a eukaryotic cell Compare and contrast the differences between substrate-level and oxidative phosphorylation Explain the relationship between chemiosmosis and proton motive force Describe the function and location of ATP synthase in a prokaryotic versus eukaryotic cell Compare and contrast aerobic and anaerobic respiration.
Think about It Do both aerobic respiration and anaerobic respiration use an electron transport chain? Think about It What are the functions of the proton motive force? Key Concepts and Summary Most ATP generated during the cellular respiration of glucose is made by oxidative phosphorylation. An electron transport system ETS is composed of a series of membrane-associated protein complexes and associated mobile accessory electron carriers. The ETS is embedded in the cytoplasmic membrane of prokaryotes and the inner mitochondrial membrane of eukaryotes.
0コメント