Question

Help!
1) Explain the similarity and difference in hydrogen bonding of the alpha-helix and the beta-pleated sheet secondary protein structure.

2) Describe the molecular structure of a starch molecule and identify its features, which make it suitable for storage in cells.
Thanks in advance.

Answer 1

3) Complete the diagram to show the formation of a dipeptide..

Answer 2

1) Hydrogen bonding in the alpha helix/beta sheet is on the backbone of the polypeptide. There is only 1 type of alpha-linkage. There are 2 types of Beta-sheets: parallel and antiparallel.

2) Starch (amylose & amylopectin) have alpha (1,4) glycosidic bonds, which is similar to glycogen structure which is stored in the muscles.

3) The Nitrogen on the N-terminal (Amino group on the far right....I think its a lysine) will act as a nucleophile and attack the C-terminal of the 1st amino acid, left amino acid (valine?)

Answer 3

Thanks. As for number 3), the C of the carboxylic group of one amino acid links to the N of the amine group of the other, right? But the thing is, I don't know how to draw the final product :/

Answer 4

Hold on...... i can show you...... give me 10 minutes

Answer 5

im at work :P

Answer 6

okay...so that cleared it up...thanks alot.

Answer 7

By the way, where do the H2O come from?

Answer 8

2 hydrogens come from the NH3 and Oxygen comes from the Carboxylic acid

Answer 9

Ohhh...thanks for helping me!