Practice MT Ans

The net charge on a molecule is influenced by the ph

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Unformatted text preview: lecule is influenced by the pH. If the pH of the urine is raised, structure 3 becomes less positively charged thus promoting its diffusion across membrane lipid bilayers from the urine into the blood. PMS language:: Passive rebasorption of a molecule from the urine into the blood is promoted if the molecule is uncharged. The proportion of a molecule with a single ionizing group that exists in uncharged form is influenced by the pH. If the pH of the urine is raised, the proportion of structure 3 in solution that exists in neutral form increases thus promoting its diffusion across membrane lipid bilayers from the urine into the blood. Question #5 (6 points) Consider the structure of the neutral, uncharged form of glutathione. Note this says pKb pKa ~ 2 O OH O C pKb ~ 4 NH 2 C (CH2)2 H CN CCN H H O CH2 O (CH2)2 C H OH pKa ~ 4 pKa ~ 8 SH Estimate the pHI of glutathione. Note: For partial credit, it is important to show your written work in a form the marker can understand. A verbal clarification of your method following exam grading will not be considered. pH pKa 2 4 2 -0.5 -1 4 0 -0.5 8 0 0 +1 +1 +0.5 -0.5 10 pH I = 2 + 4/2 = 3 8 10 Question #6 (8 points) (a) You need to do something to help distinguish two possible protein structures. Indicate whether the indicated action would be useful to do by answering YES or NO. Example Problem Action You need to distinguish between Compare a fibrous protein and a globular protein the gross shape of the proteins YES Problem Action Useful? You need to distinguish between Compare (1) a fibrous protein and the surface area/volume ratio of a globular protein the two proteins (2) a multi-domain monomeric protein the results of completely and an oligomeric protein denaturing each protein (3) a monomeric globular protein and the presence/absence of intrachain a subunit of a globular oligomeric -S-S-bonds in each polypeptide protein (4) a single domain monomeric the amino acid composition lipid-soluble protein and a single of the two proteins domain monomeric water-soluble protein Useful? YES YES NO YES (b) Now briefly explain your reasoning for one of your choices...
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This test prep was uploaded on 04/01/2014 for the course BIOL 201 taught by Professor Chowrira during the Winter '13 term at UBC.

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