chapter 4 section 1

Question 1

What is the central carbon in amino acids called?

Answer 1

The alpha (α) carbon, which is tetrahedral.

Question 2

How many common amino acids are found in proteins?

Answer 2

20 common amino acids.

Question 3

What bond links amino acids together?

Answer 3

A peptide bond.

Question 4

What are the four major classes of amino acids?

Answer 4

Nonpolar, polar uncharged, acidic, and basic

Question 5

What problem does methionine oxidation cause?

Answer 5

It contributes to protein aging and damage (e.g., in smokers’ lungs).

Question 6

How have researchers expanded amino acid chemistry?

Answer 6

By incorporating unnatural amino acids (UAAs) into proteins.

Question 7

What is one potential use of unnatural amino acids?

Answer 7

Development of novel antibodies, vaccines, or protein studies.

Question 8

What is released when a peptide bond forms?

Answer 8

A molecule of water

Question 9

Which amino acid has a unique ring structure that bonds to its own backbone nitrogen?

Answer 9

Proline.

Question 10

Which amino acids are acidic?

Answer 10

Aspartate and glutamate

Question 11

Which amino acids are basic

Answer 11

Lysine, arginine, and histidine

Question 12

Which amino acids are polar but uncharged?

Answer 12

Serine, threonine, asparagine, glutamine, tyrosine, cysteine.

Question 13

Which amino acids are nonpolar?

Answer 13

Glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan.

Question 14

What modification makes amino acids important in signaling?

Answer 14

Phosphorylation.

Question 15

Who developed methods to insert unnatural amino acids into proteins?

Answer 15

Peter Schultz and colleagues.