Biology (9th Edition)
George Johnson, Peter Raven, Kenneth Mason, Susan Singer, Jonathan B. Losos
Format: PDF / Kindle (mobi) / ePub
Committed to Excellence. This edition continues the evolution of Raven & Johnson’s Biology. The author team is committed to continually improving the text, keeping the student and learning foremost. We have integrated new pedagogical features to guide the student through the learning process. This latest edition of the text maintains the clear, accessible, and engaging writing style of past editions with the solid framework of pedagogy that highlights an emphasis on evolution and scientific inquiry that have made this a leading textbook for students majoring in biology. This emphasis on the organizing power of evolution is combined with an integration of the importance of cellular, molecular biology and genomics to offer our readers a text that is student friendly and current.
Our author team is committed to producing the best possible text for both student and faculty. The lead author, Kenneth Mason, University of Iowa, has taught majors biology at three different major public universities for more than fifteen years. Jonathan Losos, Harvard University, is at the cutting edge of evolutionary biology research, and Susan Singer, Carleton College, has been involved in science education policy issues on a national level.
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sodium–potassium pump transports sodium (Na+) and potassium (K+) across the plasma membrane. For every three Na+ transported out of the cell, two K+ are transported into it. The sodium– potassium pump is fueled by ATP hydrolysis. The affi nity of the pump for Na+ and K+ is changed by adding or removing phosphate (P), which changes the conformation of the protein. 100 part II Biology of the Cell rav32223_ch05_088-106.indd 100 11/6/09 12:02:15 PM The remarkable protein that transports these
functions. Multienzyme complexes offer the following significant advantages in catalytic efficiency: 1. The rate of any enzyme reaction is limited by how often the enzyme collides with its substrate. If a series of sequential reactions occurs within a multienzyme complex, the product of one reaction can be delivered to the next enzyme without releasing it to diffuse away. 2. Because the reacting substrate doesn’t leave the complex while it goes through the series of reactions, unwanted side
gradient for energy to form ATP. Further Experiments: What other controls would be appropriate for this type of experiment? Why is this experiment a better test of the chemiosmotic hypothesis than the acid bath experiment in Jangendorf/chapter 8 (see figure 8.16)? Figure 7.13 Evidence for the chemiosmotic synthesis of ATP by ATP synthase. www.ravenbiology.com rav32223_ch07_122-146.indd 135 chapter 7 How Cells Harvest Energy 135 11/6/09 12:40:50 PM Figure 7.14 Aerobic respiration in the
alanine is converted into pyruvate, glutamate into α-ketoglutarate (figure 7.21), and aspartate into oxaloacetate. The reactions of glycolysis and the Krebs cycle then extract the high-energy electrons from these molecules and put them to work making ATP. O Urea H2NJCJH HJCJH HJCJH HOJ C CKO NH3 HJCJH HJCJH C HO J O C J HO Glutamate O J J J J K J J J J K C K K HO J O ␣-Ketoglutarate Figure 7.21 Deamination. After proteins are broken down into their amino acid constituents,
not done this way. As the British philosopher Karl Popper has pointed out, successful scientists without exception design their experiments with a pretty fair idea of how the results are going to come out. They have what Popper calls an “imaginative preconception” of what the truth might be. Because insight and imagination play such a large role in scientific progress, some scientists are better at science than others—just as Bruce Springsteen stands out among songwriters or Claude Monet stands