C13 Proteins Flashcards
amino acids
the building blocks that connect together via covalent bonds to form proteins
amino group
a group of NH2 atoms; can pick up a proton to form NH3+
carboxyl group
a group of COOH atoms; can lose a proton to form COO-
R-group
a highly variable group of atoms bonded to the central carbon of an amino acid
hydrophilic
can readily interact with the partial charges on water
hydrophobic
cannot readily interact with the partial charges on water
peptide bond
the covalent bond that forms between the carboxyl group of one amino acid and the amino group of another
protein primary structure
the sequence of amino acids, linked via peptide bonds
protein secondary structure
formation of a-helices and B-pleated sheets, stabilized by hydrogen bonds between backbone atoms
protein tertiary structure
folding into a 3-D shape stabilized by hydrogen bonds, ionic bonds, S-S bridges, and hydrophobic interactions
ionic bond
an interaction that occurs when a positively charged ion is attracted to a negatively charged ion
hydrophobic interactions
interactions that stabilize hydrophobic regions of molecules by minimizing their contact with water
protein quaternary structure
assembly of multipart proteins from folded subunits, stabilized by hydrogen bonds, ionic bonds, S-S bridges, and hydrophobic interactions
Denaturing
“folding” or loss of 3-dimensional shape (secondary, tertiary, and quaternary structure), often via heating or changes in pH.
Catabolic enzyme
breaks bonds
doesn’t just randomly happen
anabolic enzyme
creates bonds
Monomer: amino acids
the monomers that make up proteins
how are amino acids built?
central carbons atom, amino group, carboxyl, hydrogen, side chain (r-group)
sides chains come from
functional groups
peptide formation
amino acid monomers are linked via dehydration synthesis reaction, forming peptide bonds
difference between polypeptides and proteins
polypeptide - a chain of amino acids joined together in peptide bonds
Protein - a polypeptide or multiple polypeptides
primary protein structure
the unique sequence of amino acids in a polypeptide
secondary protein structure
hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern (a-helices, and B-pleated sheets)
how are a-helixes formed?
by H-bond between oxygen in carbonyl group and an amino acid four positions down the chain
how are B-pleated sheets formed?
H-bonding between atoms on the backbone of the polypeptide chain
tertiary protein structure
three-dimensional folding pattern of a protein due to side chain interactions
cysteine side chains form _______ _______
disulfide bridges
quaternary protein structure
protein consisting of more than one amino acid chain
denaturation
changes the structure, but NOT the amino acids of the entire protein
