Becker's World of the Cell (9th Edition)
9th Edition
ISBN: 9780321934925
Author: Jeff Hardin, Gregory Paul Bertoni
Publisher: PEARSON
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Chapter 3, Problem 3.5PS
Hair Versus Silk. The a-keratin of human hair is a good example of a fibrous protein with extensive a-helical structure. Silk fibroin is also a fibrous protein, but it consists primarily of b-sheet structure. Fibroin is essentially a
(a) If you were able to grab onto both ends of an α-keratin polypeptide and pull, you would find it to be both extensible (it can be stretched to about twice its length in moist heat) and elastic (when you let go, it will return to its normal length). In contrast, a fibroin polypeptide has essentially no extensibility, and it has great resistance to breaking. Explain these differences.
(b) Can you suggest why fibroin assumes a pleated sheet structure, whereas α-keratin exists as an α helix and even reverts spontaneously to a helical shape when it has been stretched artificially?
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Chapter 2: CARBOHYDRATES
SELF-ASSESSMENT EXERCISES
I. Essay questions
1. Define and classify carbohydrates with suitable examples. Add a note on the functions of
carbohydrates.
2. Describe the structure and functions of mucopolysaccharides.
3. Give an account of the structural configuration of monosaccharides, with special reference to
glucose.
4. Discuss the structure and functions of 3 biochemically important disaccharides.
5. Define polysaccharides and describe the structure of 3 homopolysaccharides.
III. Fill…
Sweet proteins. List the key classes of glycoproteins, their defining characteristics, and their biological functions.
Chapter 3 Solutions
Becker's World of the Cell (9th Edition)
Ch. 3 - What structural features of protein molecules...Ch. 3 - Prob. 3.1CCCh. 3 - Like proteins, nucleotides are important...Ch. 3 - Polysaccharides are also important macromolecules...Ch. 3 - Prob. 3.4CCCh. 3 - Polymers and Their Properties. For each of the six...Ch. 3 - Stability of Protein Structure. Several different...Ch. 3 - Prob. 3.3PSCh. 3 - Prob. 3.4PSCh. 3 - Hair Versus Silk. The a-keratin of human hair is a...
Ch. 3 - The Permanent Wave That Isnt. The permanent wave...Ch. 3 - Features of Nucleic Acids. For each of the...Ch. 3 - Wrong Again. For each of the following false...Ch. 3 - Prob. 3.9PSCh. 3 - Prob. 3.10PSCh. 3 - Telling Them Apart. For each of the following...Ch. 3 - Prob. 3.12PSCh. 3 - Prob. 3.13PSCh. 3 - QUANTITATIVE Thinking About Lipids. You should be...Ch. 3 - Shortening. A popular brand of shortening has a...
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