prob_set_3ans - Problem Set#3 Bio 1A Name Section 1 Explain...

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Problem Set #3 Bio 1A Name____________________________ Section # ___ 1) Explain what it means to say that membranes are selectively permeable. What accounts for this selective permeability? Some molecules cross membranes more efficiently than others. Due to size, charge, hydrophobicity and the presence of transport proteins or channels in the membrane. 2) How does hydrophobcity, polarity, and charge affect molecular movement across membranes? Hydrophobic molecules can more readily cross membranes while polar and charged molecules require specific transporters or channels. 3) What is active transport? What energy source is required in this process? Transport of a molecule across a membrane against its electrochemical gradient. Energy comes from a) co-transport, b) ATP, c) light (photons) 4) What is a trans-membrane domain? What type of protein structure commonly characterizes this region of membrane proteins? How would you use this knowledge to predict whether a protein of known sequence contains a transmembrane domain? Domain of a protein which crosses a membrane. Usually a hydrophobic alpha helix. Assess hydrophobicity of successive amino acids in primary sequence. If ~20 consecutive hydrophobic aa’s, then could be transmembrane domain 5) How might a mutation in the cytoplasmic domain of the CFTR protein interfere with its function as a Cl - channel? It is possible that such a mutation might result in a structural change in CFTR which
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This note was uploaded on 04/02/2008 for the course BIO 1A taught by Professor Schlissel during the Spring '08 term at Berkeley.

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prob_set_3ans - Problem Set#3 Bio 1A Name Section 1 Explain...

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