BIOC202 Tutorial 3 Practice Questions w Answers

pdf

School

University of British Columbia *

*We aren’t endorsed by this school

Course

202

Subject

Chemistry

Date

Feb 20, 2024

Type

pdf

Pages

3

Uploaded by Drsarahmiles099842

Report
BIOC202 Tutorial 3 | Elyn Rowe | 2024 Dr. Williams has suggested that we spend a bit of time going through some practice midterm questions in more depth, and has provided a relevant textbook question to look at. I’ve slightly changed the short answer questions pulled from the midterm so you have to do a bit more thinking than opening up the answer key PDF. Modified Q3 from Practice Midterm 1. Biochemists often use a helix wheel to visualize placement of amino acids ( αα ) in an α - helix. In a helix wheel, #1 corresponds to the first αα in the sequence, #2, the second, etc. etc. The sequence listed below forms an α -helix. Using the helix wheel provided, analyze this sequence and comment on its specific properties. SWLS NHVI QAMA EIDK NF
BIOC202 Tutorial 3 | Elyn Rowe | 2024 Modified Q4 from Practice Midterm 2a. Draw an anti-parallel β -sheet composed of two β -strands with each strand being 4 residues long. Just draw the backbone (i.e. do NOT draw R groups) and indicate any hydrogen bonds. How would the hydrogen bonding pattern in a parallel β -sheet be different? 2b. Relative to the β -sheet you drew in 4a, describe the orientation of the R groups in the sheet relative to the plane of the exam page.
BIOC202 Tutorial 3 | Elyn Rowe | 2024 The Final Boss Lehninger, Chapter 4 Q4 3. Effect of pH on the conformation of - helical secondary structures: Specific rotation is a measure of a solution’s capacity to rotate circularly polarized light. The unfolding of the - helix of a polypeptide to a randomly coiled conformation is accompanied by a large decrease in specific rotation. Polyglutamate, a polypeptide made up of only L-Glu residues, is an -helix at pH 3. When the pH is raised to 7, there is a large decrease in specific rotation of the solution. Similarly, polylysine (L-Lys residues) is an -helix at pH 10, but at pH 7 its specific rotation also decreases. Explain the effect of the pH changes on the conformations of poly(Glu) and poly(Lys). Why does this transition occur over such a narrow range of pH?
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help