Chapter 19- Amino Acids And Proteins Flashcards
Acidic amino acid
An amino acid has an R group with a carboxylate (-COO) ion
A (alpha) helix
A secondary level of protein structure, in which hydrogen bonds connect the N-H of one peptide bond with the ( C=O) of a peptide bond further down the chain to form a coiled or corkscrew structure
A-keratins
Fibrous proteins containing mostly a Helixes found in hair,nails, and skin
Amino acids
The building block of proteins, consisting of an ammonium group,ma carboxylate group, and a unique R group attached to the a carbon
Basic amino acid
An amino acid that contains an R group with an ammonium (-NH3+) ion
B-pleated sheet
A secondary level of protein structure that consists of hydrogen bonds between peptide links in parallel polypeptides
C terminal
The end amino acid In a peptide chain with a free carboxylate (-COO) group
Collagen
The most abundant form of protein in the body, which is composed if fibrils of triple Helixes with hydrogen bonding between the -OH groups ofnhydroxyproline and hydroxylisine
Denaturation
The loss of secondary or tertiary protein structure caused by heat, acids, bases, organic compounds, heavy metals, and/or agitation
Disulfide bond
Covalent -S-S- bonds that firm between the -SH groups of two cysteines in a protein to stabilize the tertiary structure
Electrophoresis
The use of electrical current to separate proteins or other charged molecules with different isoelectric points
Essential amino acids
Amino acids that must be supplied by the diet because they are not synthesized by the body
Fibrous proteins
Proteins that are insoluble in water; consisting of polypeptide chains with a- Helixes or b-pleated sheets, and comprising with fibers of hair, skin, nails, and silk
Globular proteins
Proteins that acquire a compact shape from attractions between the R groups of the amino acids in the protein
Hydrogen bonds
The interactions between water and the polar R groups such as -OH, -NH2, and -COOH on the outside surface of polypeptide chain
Hydrophilic reactions
The attractions between polar R groups on the protein surface and water
Water attracting
Hydrophobic interactions
The attractions between non polar R groups on the inside of a globular protein
Water fearing
Isoelectric point (pI)
The pH at which amino acid exists as a zwitterion with a net charge of zero
N terminal
The end amino acid in a peptide with a free -NH3+ group
Nonpolar amino acids
Amino acids with Nonpolar R groups containing only C and H atoms
Peptide
The combination of two or more amino acids joined by peptide bonds; di peptide, tripeptide, and so on
Polar amino acids (neutral)
Amino acids with polar R groups
Primary structure
The specific sequence of the amino acids in a protein
Protein
Polypeptides containing many amino acids linked together by peptide bonds that are biologically active
Quaternary structure
A protein structure in which two or more protein subunits form an active protein
Salt bridge
The attraction between the ionized R groups of basic and acidic amino acids in the tertiary structure of a protein
Secondary structure
The formation of an a-helix, b-pleated sheet, or triple helix
Tertiary structure
The folding of the secondary structure of a protein into a compact structure that is stabilized by the interactions of R groups such as ionic and disulfide bonds
Triple helix
The protein structure found in collagen consisting of three polypeptide chains woven together like a braid
Zwitterion
The diplomat form of an amino acid consisting of two oppositely charged ionic regions, -NH3+, and -COO
