2.7.2 Amino Acids: The R Groups

Question 1

note

Answer 1

• there are 20 amino acids, each with a different R group
• the properties of the different R groups lead to interactions between R groups within a protein, which in turn determines the conformation, or shape, of the protein
• amino acids can be placed into one of three general categories based on their R groups: charged, polar, and nonpolar.

Question 2

charged amino acids

Answer 2

• Aspartic acid
• Glutamic acid
• Lysine
• Arginine
• Histidine

Question 3

polar amino acids

Answer 3

• Threonine
• Cysteine
• Tyrosine
• Asparagine
• Glutamine
• Serine

Question 4

nonpolar amino acids

Answer 4

• Glycine
• Alanine
• Valine
• Leucine
• Isoleucine
• Methionine
• Phenylalanine
• Tryptophan
• Proline

Question 5

R groups

Answer 5

• can be acidic, basic, or neutral

Question 6

Threonine is an amino acid whose R group contains an alcohol group. What class of amino acid is threonine expected to be in?

Answer 6

• polar

Question 7

Glycine has the simplest R group of the amino acids, a hydrogen. What class of amino acid is glycine in?

Answer 7

• nonpolar

Question 8

The R group of amino acids

Answer 8

• is different for each amino acid