Chapter 15 - Structure and bonding in food molecules

essential amino acids

PVT TIM HALL

complementary proteins

dietary proteins whose amino acid assortments compliment each other in a way that the essential amino acids missing from one are supplied by the other

zwitterion

a dipolar ion formed when the amino and carboxyl groups in an amino acid or polypeptide are both charged

secondary structure

folding or coiling of the polypeptide chain to form a-helices or B-pleated sheets through H-bonds between different -NH and -C=O groups

compare a-helices vs B-pleated sheets

H-bonds in beta sheets form between -NH groups in the backbone of one strand the -C=O groups in the backbone of the adjacent strands. H-bonds in a-helices form between -NH groups and -C=O groups four residues prior creating a coiled structure

cellulose bonding

alternating CH2OH groups allow for the alignment of OH groups between neighbouring molecules which form H-bonds

glycosidic link

The ether link formed when the hydroxyl groups on two monosaccharides react.