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Question 1 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 Mr 50,000 and the average lipid is 750.) Question 1 answers 1 50 200 10,000 50,000 Question 2 The shortest  helix segment in a protein that will span a membrane bilayer has about _____ amino acid residues. Question 2 answers 5 20 50 100 200 Question 3 According to the current model for HIV infection, which of the following is not involved in the process of membrane fusion? Question 3 answers A cell surface co-receptor protein A cell surface receptor protein A viral glycoprotein complex The viral chromosome The viral envelope Question 4 Consider the transport of glucose into an erythrocyte by facilitated diffusion. When the glucose concentrations are 5 mM on the outside and 0.1 mM on the inside, the free-energy change for glucose uptake into the cell is: (These values may be of use to you: R = 8.315 J/mol•K; T = 298 K; 9 (Faraday constant) = 96,480 J/V; N = 6.022 x1023/mol.) Question 4 answers less than 2 kJ/mol. about 10 kJ/mol. about 30 kJ/mol. about –30 kJoule/mol. impossible to calculate without knowledge of the membrane potential. Question 5 Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to: Question 5 answers diacylglycerol + inositol triphosphate. diacylglycerol + inositol+ phosphate. glycerol + inositol + phosphate. glycerol + phosphoserine. phosphatidyl glycerol + inositol + phosphate. Question 6 Steroid hormones are carried on specific carrier proteins because the hormones: Question 6 answers are too unstable to survive in the blood on their own. cannot dissolve readily in the blood because they are too hydrophobic. cannot find their target cells without them. need them in order to pass through the plasma membrane. require subsequent binding to specific receptor proteins in the nucleus. Question 7 Ubiquitin is a: Question 7 answers component of the electron transport system. protease. protein kinase. protein phosphorylase. protein that tags another protein for proteolysis. Question 8 Which one of the following signaling mechanisms is used most predominantly in plants? Question 8 answers Cyclic-nucleotide dependent protein kinases DNA-binding nuclear steroid receptors G protein-coupled receptors Protein serine/threonine kinases Protein tyrosine kinases Question 9 Which of the following does not involve cyclic AMP? Question 9 answers Regulation of glycogen synthesis and breakdown Regulation of glycolysis Signaling by acetylcholine Signaling by epinephrine Signaling by glucagon Question 10 The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system. Question 10 answers G protein ligand-gated receptor-enzyme serpentine receptor voltage-gated

In an attempt to design a treatment for Botulism, you have been asked to design a five-turn alpha-helix that is destined to have half its circuference in the interior of a protein. Draw a helical wheel projection of your prototype alpha-helix using N for nonpolar and P for polar residues. For example, if N1 occupied the 12 o'clock position of the helical wheel, what positions would residues 2,3,4,5,6 etc. occupy and would they be polar or nonpolar? How many residues will there be? After you have drawn your helical wheel, write out the primary sequence of the protein (using N and P) for the five-turn alpha-helix. I know what is a five-turn alpha-helix, but I'm pretty confused with the rest of the information provided in this question. Can some one help me... Thanks