Lecture 2 Questions

Question 1

At physiologic pH (7.4), what is the charge on the side chain of Glu? Of Arg?

Answer 1

Negative; positive

Question 2

In a soluble protein, would Leu would most likely be located on the inside or the outside of the folded protein? What if it were a membrane protein?

Answer 2

Inside; in the portion of the protein spanning the membrane

Question 3

Make sure you can identify an alpha helix and a beta sheet in a diagram.

Answer 3

diagrams…

Question 4

In the collagen alpha chain (see lecture powerpoint), what amino acid repeats every third position? Why is it special? (from Flashcards)

Answer 4

Gly; fits into the small space because it only has H for a sidechain

Question 5

What can a Western blot tell you about a protein?

Answer 5

If it is present in the sample, approximate size (M.W.), whether there are multiple modified forms (sometimes). It does not say anything about protein structure or activity.