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Answers to Chapter Four

ANSWERS TO CHAPTER FOUR

1. Answer: b. Each of these is a part of the triglyceride molecule, except for a carboxylic acid portion. It is basically three fatty acids connected to glycerol via an ester bond. 2. Answer: d. The phospholipid is very similar to the triglyceride molecule; however, instead of three fatty acids, it has two fatty acids and a phosphate group in place of the third fatty acid moiety seen in the triglyceride molecule. 3. Answer: c. Each of these is associated with fatty acid synthesis except for muscle tissue. In each of the listed areas, fatty acids can be made after acetyl

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CoA is made through the glycolytic process from glucose in the cytoplasm. 4. Answer: b. Palmitic acid is a 16-carbon fatty acid that is the endpoint of fatty acid synthesis with fatty acid synthase. It takes other reactions to lengthen this fatty acid or to desaturate it. 5. Answer: a. Glycolipids are only found on the outside of the cell membrane.

They have their carbohydrate portion sticking out from the cell. 6. Answer: c. Peripheral proteins lie on the outer surface of the cell. They are hydrophilic in general and can be isolated without necessarily disrupting the cell membrane. 7. Answer: d. The outer part of a cell is called the glycocalyx, because it has carbohydrates attached to the protein molecules, which can be transmembrane proteins or surface proteins. 8. Answer: a. Transporter proteins transport ions and small molecules across the cell membrane because otherwise the cell membrane would be more impermeable to these types of molecules. 9. Answer: c. Membrane receptor proteins allow for chemical signaling both inside and outside of the cell. 10. Answer: b. Integral monotopic proteins do not pass all the way through the membrane; however, transmembrane proteins can pass through the cell membrane bilayer several times.

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