Search Results for: Chemical equation
20.1 ATP—the Universal Energy Currency
Learning Objectives Describe the importance of ATP as a source of energy in living organisms. Adenosine triphosphate (ATP), a nucleotide composed of adenine, ribose, and three phosphate groups, is perhaps the most important of the so-called energy-rich compounds in a cell. Its concentration in the cell varies from 0.5 to 2.5 mg/mL of cell fluid. Read more »
Introduction
Chapter 20 Energy Metabolism Opening Essay The discovery of the link between insulin and diabetes led to a period of intense research aimed at understanding exactly how insulin works in the body to regulate glucose levels. Hormones in general act by binding to some protein, known as the hormone’s receptor, thus initiating a series of Read more »
20.8 End-of-Chapter Material
Chapter Summary To ensure that you understand the material in this chapter, you should review the meanings of the bold terms in the following summary and ask yourself how they relate to the topics in the chapter. Metabolism is the general term for all chemical reactions in living organisms. The two types of metabolism are Read more »
20.4 Stage III of Catabolism
Learning Objectives Describe the reactions of the citric acid cycle. Describe the function of the citric acid cycle and identify the products produced. Describe the role of the electron transport chain in energy metabolism. Describe the role of oxidative phosphorylation in energy metabolism. The acetyl group enters a cyclic sequence of reactions known collectively as Read more »
19.7 End-of-Chapter Material
Chapter Summary To ensure that you understand the material in this chapter, you should review the meanings of the bold terms in the following summary and ask yourself how they relate to the topics in the chapter. A cell’s hereditary information is encoded in chromosomes in the cell’s nucleus. Each chromosome is composed of proteins Read more »
20.2 Stage I of Catabolism
Learning Objective Describe how carbohydrates, fats, and proteins are broken down during digestion. We have said that animals obtain chemical energy from the food—carbohydrates, fats, and proteins—they eat through reactions defined collectively as catabolism. We can think of catabolism as occurring in three stages (Figure 20.4 “Energy Conversions”). In stage I, carbohydrates, fats, and proteins Read more »
18.6 Enzyme Action
Learning Objective Describe the interaction between an enzyme and its substrate. Enzyme-catalyzed reactions occur in at least two steps. In the first step, an enzyme molecule (E) and the substrate molecule or molecules (S) collide and react to form an intermediate compound called the enzyme-substrate (E–S) complex. (This step is reversible because the complex can Read more »
16.7 Polysaccharides
Learning Objective Compare and contrast the structures and uses of starch, glycogen, and cellulose. The polysaccharides are the most abundant carbohydrates in nature and serve a variety of functions, such as energy storage or as components of plant cell walls. Polysaccharides are very large polymers composed of tens to thousands of monosaccharides joined together by Read more »
16.6 Disaccharides
Learning Objectives Identify the structures of sucrose, lactose, and maltose. Identify the monosaccharides that are needed to form sucrose, lactose, and maltose. In Section 16.4 “Cyclic Structures of Monosaccharides”, you learned that monosaccharides can form cyclic structures by the reaction of the carbonyl group with an OH group. These cyclic molecules can in turn react Read more »
14.5 Reactions of Alcohols
Learning Objectives Give two major types of reactions of alcohols. Describe the result of the oxidation of a primary alcohol. Describe the result of the oxidation of a secondary alcohol. Chemical reactions in alcohols occur mainly at the functional group, but some involve hydrogen atoms attached to the OH-bearing carbon atom or to an adjacent Read more »
