Amino Acids

Question 1

Proteins and amino acids and bonds formed

Answer 1

• diverse and abundant macromolecules
• building blocks of proteins through condensation polymerization to form a peptide bond / 20 natural occurring in people

Question 2

What determines chemical properties of peptides

Answer 2

-since -COOH- And -NH2- are bound in peptide bonds the R group will determine chemical reactions and physical properties as well

Question 3

Classification of amino acids, describe briefly (esp 1st) and polarity at physiologic pH

Answer 3

-By polarity of R groups

1 Non-polar - side group does not gain or lose protons or participate in H2 or ionic bonding ( not charged )

• Glycine / Alanine / Valine / Leucine / Isoleucine / Phenylalanine / Tryptophan / Proline / Methionine
• in polar environments these side groups are located in interior of protein ( hydrophobic effect due to non-polar R group. These folds protein giving rise to 3D structure me
• found outside of protein in non-polar environment

2 Basic side group -has NH2 in R group which accepts protons. +ve at physiologic pH
-Histidine / Lysine / Argenine

3 Acidic side group - COOH which donates protons , -ve at physiologic pH
-Aspartic Acid / Glutamatic acid

4 Uncharged polar groups -have net 0 charge at physiologic Ph
-Serine / Threonine / Tyrosine / Asparagine / Glutamine / Cysteine

Question 4

Cysteine and Disulfide bridge

Answer 4

-two cysteine amino acids can be oxidized and form a disulfide bridge

Question 5

Criteria for Abbreviations

Answer 5

• Unique 1st letter
• Most common occurring given priority of 1st letter
• similar sounding letter to the acid
• Letter close initial

Question 6

Amino acids and isomerism and whats the configuration of aas in natural proteins

Answer 6

• if Chiral center present

- all are L configured

Question 7

Isoelectric point

Answer 7

-pH at which an amino acid is at 0 pH