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Unformatted text preview: Chapter 11 Biological Membranes and Transport Multiple Choice Questions 1. The composition and architecture of membranes Page: 372 Difficulty: 2 Ans: C Which one of the following statements about membranes is true? A) Most plasma membranes contain more than 70% proteins. B) Sterol lipids are common in bacterial plasma membranes. C) Sterol lipids are common in human cell plasma membranes. D) Sterol lipids are common in plant cell plasma membranes. E) The plasma membranes of all cell types within a particular organism have basically the same lipid and protein composition. 2. The composition and architecture of membranes Page: 372 Difficulty: 3 Ans: C The inner (plasma) membrane of E. coli is about 75% lipid and 25% protein by weight. How many molecules of membrane lipid are there for each molecule of protein? (Assume that the average protein is M r 50,000 and the average lipid is 750.) A) 1 B) 50 C) 200 D) 10,000 E) 50,000 3. The composition and architecture of membranes Page: 372 Difficulty: 2 Ans: A Which of these statements about the composition of biological membranes is false? A) In a given eukaryotic cell type (for example, a hepatocyte), all intracellular membranes have essentially the same complement of lipids and proteins. B) The carbohydrate found in membranes is virtually all part of either glycolipids or glycoproteins. C) The plasma membranes of the cells of vertebrate animals contain more cholesterol than the mitochondrial membranes. D) The ratio of lipid to protein varies widely among cell types in a single organism. E) Triacylglycerols are not commonly found in membranes. 4. The composition and architecture of membranes Page: 372 Difficulty: 1 Ans: C Which of these statements about the composition of membranes is true? A) All biological membranes contain cholesterol. B) Free fatty acids are major components of all membranes. B) The inner and outer membranes of mitochondria have different protein compositions. D) The lipid composition of all membranes of eukaryotic cells is essentially the same. E) The lipid:protein ratio varies from about 1:4 to 4:1. Chapter 11 Biological Membranes and Transport 5. The composition and architecture of membranes Pages: 375-377 Difficulty: 1 Ans: E Membrane proteins: A) are sometimes covalently attached to lipid moieties. B) are sometimes covalently attached to carbohydrate moieties. C) are composed of the same 20 amino acids found in soluble proteins. D) diffuse laterally in the membrane unless they are anchored. E) have all of the properties listed above. 6. The composition and architecture of membranes Page: 375 Difficulty: 2 Ans: A Peripheral membrane proteins: A) are generally noncovalently bound to membrane lipids....
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- Spring '11
- Chemistry, Membrane protein, Biological Membranes and Transport