Amino Acids, Peptides, and Proteins (CH1)

Question 1

What amino acids are known for having long alkyl side chains and what special properties do they hold?

Answer 1

They are strongly hydrophobic and more likely to be found on the interior of a protein:

• Alanine
• Isoleucine
• Leucine
• Valine
• Phenylalanine

Question 2

What amino acids are known for being hydrophillic?

Answer 2

Charged side chains (+ or -)

Question 3

Regular Amino Acid Equation?

Answer 3

(pka NH group + pka COOH group)/2

Question 4

Acidic Amino Acid Equation?

Answer 4

(pka R group + pka COOH group)/2

Question 5

Basic Amino Acid Equation?

Answer 5

(pka R group + pka NH group)/2

Question 6

What is special about glycine?

Answer 6

• Alpha carbon is not chiral

- VERY flexible

Question 7

What two amino acids are considered alpha helix breakers?

Answer 7

Proline (which has two alpha carbons) and Glycine

Question 8

How are secondary structures held together?

Answer 8

Hydrogen bonding between nearby amino acids (intermolecular) and intramolecular hydrogen bonding.

Question 9

What are two secondary structures?

Answer 9

• Alpha helices

- Beta-pleated sheets

Question 10

Explain alpha helices.

Answer 10

• Rodlike structure
• Peptide coils clockwise around the central axis
• Side chains point away

Question 11

Explain beta-pleated sheets.

Answer 11

• Parallel/Anti-Parallel
• Pleated or Rippled Shape
• R groups point above and below

Question 12

How are tertiary structures held together?

Answer 12

Hydrogen bonding and salt bridges (acid-base interactions of AA with charged R groups).

Question 13

What breaks disulfide bonds?

Answer 13

Urea