Chapter 2 Chemical Basis of Life

Chapter 2 Chemical - Chapter 2 Chemical Basis of Life Page 51 Questions 1 Why is a knowledge of chemistry essential to understanding physiology a

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Chapter 4 Cellular Metabolism Page 116 1. What are the general functions of anabolism and catabolism? a. Anabolism – larger molecules are constructed from smaller ones, requiring output of energy. b. Catabolism – larger molecules are broken down into smaller ones, releasing energy. 2. What type of molecule is formed by the anabolism of monosaccharides? Of glycerol and fatty acids? Of amino acids? a. Anabolism of Monosaccharides – Dehydration synthesis joins many simple sugar molecules to form a larger molecule of Glycogen. Pasta is broken down into monosaccharides. They are absorbed into the blood stream, then carried to blood cells. Here, dehydration synthesis joins the sugars to form glycogen, which stores the energy til needed. b. Glycerol and Fatty Acids – join by dehydration synthesis in fat tissue cells to form fat molecules. c. Amino Acids – Dehydration synthesis also builds protein molecules by joining amino acid molecules. 3. Distinguish between dehydration synthesis and hydrolysis. a. Hydrolysis – decomposes carbohydrates, lipids and proteins. Dehydration synthesis joins molecules to form larger molecules. Hydrolysis is the reverse of dehydration synthesis. It breaks down Carbohydrates into monosaccharides; fats into glycerol and fatty acids; and proteins into amino acids and nucleic acids into nucleotides. Page 117 1. What is a rate-limiting enzyme? a. The first enzyme in a series. This position is important because some intermediate product of the pathway might accumulate if an enzyme occupying another location in the sequence were rate limiting.
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2. How can negative feedback control a metabolic pathway? a. The end product of a metabolic pathway inhibits the rate-limiting enzyme. This is an example of negative feedback. Accumulating product inhibits the pathway, and synthesis of the product falls. When the concentration of product decreases, the inhibition lifts and more product is synthesized. A single enzyme can control a whole pathway, stabilizing the rate of production. Page 118 1. What is an enzyme? a. Most Enzymes are globular proteins that promote specific chemical reactions in cells by lowering the activation energy required to start these reactions. May be inactive until it combines with a non protein component that either helps the active site attain its appropriate shape or helps bind the enzyme to the substrate. This substance is called the cofactor – ion of an element or small organic molecule – Coenzyme. 2. How can an enzyme control the rate of a metabolic reaction? a. The enzymes are needed to make metabolic reactions possible. They are needed in only small amounts because as they work, they are not consumed and can function repeatedly. Each chemical reaction of cellular metabolism is controlled by a specific enzyme. 3.
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This note was uploaded on 02/12/2009 for the course SCI 1234 taught by Professor Mrs.thomas during the Spring '09 term at Hinds CC.

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Chapter 2 Chemical - Chapter 2 Chemical Basis of Life Page 51 Questions 1 Why is a knowledge of chemistry essential to understanding physiology a

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