functions of proteins - Answers transport, hormones, catalysis, structure, protection
transport - Answers Proteins help to move molecules around the cell and organism. Hemoglobin is a
blood-based protein that carries oxygen from the lungs to tissue
Hormones - Answers These molecules communicate messages between cells. Relaxin is a protein
hormone that helps women during childbirth by relaxing pelvic ligaments to make delivery easier
Catalysis - Answers Enzymes speed up, or catalyze, chemical reactions. Protease, an enzyme, breaks
down proteins in cells to help organisms recycle unneeded proteins. This enzyme is also added to
laundry detergent to degrade stains with protein (i.e. blood or food)
Structure - Answers These proteins give strength to cells, organelles, and tissues. Collagen is the
structural protein found in cartilage, skin, and tendons
Protection: - Answers The human body protects itself from outside proteins and toxins by making
proteins called antibodies to fight the foreign invaders
amino acids - Answers the monomers used as building blocks of proteins
non-polar aliphatic - Answers simplest, straight chain amino acids (Glycine, Alanine, Valine, Proline,
Leucine, Isoleucine, Methionine)
non-polar aromatic groups - Answers similar to aliphatic in that they are non-polar, but the side chains
of these compounds contain a ring of carbons as an aromatic functional group (Phenylalanine,
Trptophan, Tyrosine)
polar, but neutral, amino acids - Answers contain side chains that have a dipole, and most can hydrogen
bond. unlike the non-polar groups, are often found on the outside of the protein and in contact with
water (Serine, Threonine, Cysteine, Asparagine, Glutamine)
acidic amino acids - Answers have side chains with pKa values smaller than 7 (Aspartic Acid, Glutamic
Acid)
Basic amino acids - Answers have a pKa that is near or greater than pH = 7, which means their side
chains are normally positively charged (Arginine, Lysine, Histidine)
disulfide bond - Answers unique amino acid is cysteine, a neutral, polar amino acid shown earlier. Its
side chain is uncharged, but two cysteines can react together to form a disulfide bond by their sulfur
atoms, forming a covalent bond
polypeptides - Answers Amino acids joined together into long chains. When the number of residues is 99
or less, we say, formally, that it is a polypeptide. After 100 residues have been added together, it is said
that the molecule has attained the status of a protein.