Chapter 6 – Protein: Amino Acids
After completing Chapter 6, the student will be able to:
Describe how the chemical structure of proteins differs from the structures of carbohydrates and fats.
List the 9 essential amino acids.
Trace the digestion of protein and list the enzymes needed to complete the process.
Explain the process used by the body to synthesize new proteins.
List the 8 major functions of protein in the body.
Describe nitrogen balance and provide examples of positive nitrogen balance, negative nitrogen balance, and
Describe deamination, where it occurs in the body, the products produced, and the fate of these products.
Discuss the factors used to evaluate protein quality.
Describe the diseases that result from inadequate intake of protein and protein-kcalories.
10. Discuss the health effects of over-consumption of protein.
11. Calculate the protein needed daily using the RDA for protein.
12. Discuss the health risks of protein and amino acid supplements.
13. Define nutritional genomics and explain its potential uses in health care.
The Chemist’s View of Proteins
are made from 20 different amino acids, 9 of which are essential. Each amino acid has an amino
group, an acid group, a hydrogen atom, and a side group. It is the side group that makes each amino acid
unique. The sequence of amino acids in each protein determines its unique shape and function.
Have unique side groups that result in differences in the size, shape and electrical charge of an amino
Nonessential amino acids,
amino acids, are ones the body can create.
Nonessential amino acids include alanine, arginine, asparagines, aspartic acid, cysteine, glutamic acid,
glutamine, glycine, proline, serine, and tyrosine.
Essential amino acids,
amino acids, must be supplied by the foods people
consume. Essential amino acids include histidine, isoleucine, leucine, lysine, methionine,
phenyalanine, threonine, tryptophan, and valine.
Conditionally essential amino acids
refer to amino acids that are normally nonessential but essential
under certain conditions.
Amino acid chains are linked by
in condensation reactions.
have two amino acids bonded together.
have three amino acids bonded together.
have more than two amino acids bonded together.
Amino acid sequences are all different, which allows for a wide variety of possible sequences.
Hydrophilic side groups are attracted to water.
Hydrophobic side groups repel water.
Coiled and twisted chains help to provide stability.
4. Protein Functions
Some carry and store materials.
b. Some provide strength.