FIGURE 17. 6 The three stages of catabolism FIGURE 17.6 The three stages of catabolism. Stage 1: Proteins, polysaccharides, and lipids are broken down into their component building blocks, which are relatively few in number. Stage 2: The various building blocks are degraded into the common product, the acetyl groups of acetyl-CoA. Stage 3: Catabolism converges to three principal end products: water, carbon dioxide, and ammonia. Fig. 17-6, p. 546

ACTIVE FIGURE 18. 1 The glycolytic pathway ACTIVE FIGURE 18.1 The glycolytic pathway. Test yourself on the concepts in this figure at http://chemistry.brookscole.com/ggb3 Fig. 18-1, p. 580

FIGURE 18.2 In the first phase of glycolysis, five reactions convert a molecule of glucose to two molecules of glyceraldehyde-3-phosphate. Fig. 18-2, p. 581

Via Facilitated diffusion ANIMATED FIGURE 18.4 Phosphorylation of glucose to glucose- 6-phosphate by ATP creates a charged molecule that cannot easily cross the plasma membrane. See this figure animated at http://chemistry. brookscole.com/ggb3 Fig. 18-4, p. 584

Anaerobic Fate of Pyruvate Yeast Muscle FIGURE 18.30 (a) Pyruvate reduction to ethanol in yeast provides a means for regenerating NAD+ consumed in the glyceraldehyde-3-P dehydrogenase reaction. (b) In oxygen-depleted muscle, NAD+ is regenerated in the lactate dehydrogenase reaction. Fig. 18-30, p. 598