Name ______________________________________
Chapter thirteen assignment: Due 28 November 2011
** Please include your last name in the saved document's name, as a precaution against
blackboard misbehavior. For example "YourLastName_HW13.doc". Remember to
upload a file; pdf, doc and .docx formats allow me to provide commentary in your
problem set.**
The text-book questions from Chapter 13 under number 1 below will all be graded
for points along with questions 2 and 3.
(20 points total)
You are also encouraged to do textbook questions 29-33, 35-67 for your own benefit.
1
From the book (7 points = 2+3+2 points each)
46, 48, 66 (tricky)
2
(6 points)
a
Look at Figure 13.16.
List the amino acids that include an alcohol functional group as part of their side chain.
List the amino acids that include a carboxylic acid functional group as part of their side
chain.
List the amino acids that include a simple amine functional group as part of their side
chain.
List the amino acids that include an amide functional group as part of their side chain.
List the amino acids that include a benzene ring as part of their side chain.
List the amino acids that include an S atom as part of their side chain. Which of these is
able to form -S-S- bonds ?
(This question seeks to make the point that a single protein is equipped with a diverse
array of chemical 'tools' with which to do its job.)
3
(1 point)
What type of secondary structure dominates in the protein depicted in Figure 13.24 ?
4
(2 points)
Red beans are mostly starch, by weight. Why do beans swell up so much when they are
cooked in a soup whereas butter does not swell up in the course of cooking ? (For full
marks mention a functional group that also features in question 2.)
5
(2 points)
Very small proteins can act as detergents. (In fact frog skin is rich in such peptides
because they disrupt the cell membranes of bacteria that might otherwise infect the
wounds frogs occasionally get.) Refresh your memory as to what properties a detergent
molecule must have and then propose two amino acids that should be present in a
dipeptide to enable it to act as a detergent. (Hint: make your choices based on the
properties of the side chains.)
6
(2 points)
A human cell is 2 µm long however each cell carries 3.1 billion base-pairs of DNA.
Imagine that all that DNA constitutes a single long molecule instead of 23 (your 23
chromosomes). Given that each base pair adds 0.34 nm to the length of a DNA molecule,
calculate the length of your one mega-molecule. (Note that the numbers above are all for
one copy of your genome, in fact each cell contains two different copies of the DNA, one
from each parent.)