Basicmedical Key

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…

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)…

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…

47 The Extracellular Matrix and Connective Tissue Many of the cells in tissues are embedded in an extracellular matrix that fills the spaces between cells and binds cells and tissue…

14 Translation: Synthesis of Proteins Proteins are produced by the process of translation, which occurs on ribosomes and is directed by messenger RNA (mRNA). The genetic message encoded in DNA…

28 Gluconeogenesis and Maintenance of Blood Glucose Levels During fasting, many of the reactions of glycolysis are reversed as the liver produces glucose to maintain blood glucose levels. This process…

33 Metabolism of Ethanol Ethanol is a dietary fuel that is metabolized to acetate principally in the liver, with the generation of reduced nicotinamide adenine dinucleotide (NADH). The principal route…

45 Metabolism of Muscle at Rest and during Exercise There are three types of muscle cells: smooth, skeletal, and cardiac. In all types of muscle, contraction occurs via an actin/myosin…

1 Metabolic Fuels and Dietary Components Fuel Metabolism. We obtain our fuel primarily from the macronutrients (i.e., carbohydrates, fats, and proteins) in our diet. As we eat, our foodstuffs are…

26 Formation and Degradation of Glycogen Glycogen is the storage form of glucose found in most types of cells. It is composed of glucosyl units linked by α-1,4-glycosidic bonds, with…