Intertissue Relationships in the Metabolism of Amino Acids
40 Intertissue Relationships in the Metabolism of Amino Acids The body maintains a relatively large free amino acid pool in the blood, even during fasting. As a result, tissues have…
Structure of the Nucleic Acids
11 Structure of the Nucleic Acids Nucleotides in DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleotides are the monomeric units of the nucleic acids, DNA (deoxyribonucleic acid) and RNA (ribonucleic…
Regulation of Enzymes
9 Regulation of Enzymes In the human body, thousands of diverse enzymes are regulated to fulfill their individual functions without waste of dietary components. Thus, with changes in our physiologic…
Digestion, Absorption, and Transport of Carbohydrates
21 Digestion, Absorption, and Transport of Carbohydrates Carbohydrates are the largest source of dietary calories for most of the world’s population. The major carbohydrates in the U.S. diet are starch,…
Purine and Pyrimidine Metabolism
39 Purine and Pyrimidine Metabolism Purines and pyrimidines are required for synthesizing nucleotides and nucleic acids. These molecules can be synthesized either from scratch, de novo, or salvaged from existing…
Cellular Bioenergetics: Adenosine Triphosphate and O2
20 Cellular Bioenergetics: Adenosine Triphosphate and O2 Bioenergetics refers to cellular energy transformations. The Adenosine Triphosphate–Adenosine Diphosphate (ATP–ADP) Cycle. In cells, the available free energy of fuels is transformed into…
Basic Concepts in the Regulation of Fuel Metabolism by Insulin, Glucagon, and Other Hormones
19 Basic Concepts in the Regulation of Fuel Metabolism by Insulin, Glucagon, and Other Hormones All cells use adenosine triphosphate (ATP) continuously and require a constant supply of fuels to…
Enzymes as Catalysts
8 Enzymes as Catalysts Enzymes are proteins that act as catalysts, which are compounds that increase the rate of chemical reactions (Fig. 8.1). Enzyme catalysts bind reactants (substrates), convert them…
Oxygen Toxicity and Free-Radical Injury
25 Oxygen Toxicity and Free-Radical Injury O2 is both essential to human life and toxic. We are dependent on O2 for oxidation reactions in the pathways of adenosine triphosphate (ATP)…
Tetrahydrofolate, Vitamin B12, and S-Adenosylmethionine
38 Tetrahydrofolate, Vitamin B12, and S-Adenosylmethionine Groups that contain a single-carbon atom can be transferred from one compound to another. These carbon atoms may be in a number of different…
