Which of the following bonds is not created by a condensatio

Which of the following bonds is not created by a condensation/dehydration reaction?

a) peptide bond (between amino acids)

b) phosphodiesterase bond (between nucleotides)

c) glycosidic bond (between sugars)

d) ester linkage (connects glycerol to fatty acid)

e) they are all created by dehydration reactions

Solution

e) they are all created by dehydration reactions

In carbohydrates,the sub-units to be joined are monosaccharides like glucose.The bond so formed is called a glycosidic bond.
In proteins,the sub-units to be joined are amino-acids to form peptide bonds.

In lipids glycerol provides up to three -OH groups to react with -COOH (carboxylic acid groups) on so called fatty acids.Once again this results in -O- bridges forming between the glycerol and each fatty acid chain.The links so formed are called ester bonds.
Glycerol attached to one fatty acid chain is called a monoglyceride;glycerol molecules with two fatty acid chains are diglycerides,glycerol with three attached fatty acid chains are triglycerides. A similar ester bond can be used to attach a single group containing phosphate,resulting in a phospholipid.
Different nucleotides (each composed of a base,pentose sugar and a phosphate group) are joined by condensation reactions to form DNA and RNA.The outer sections of the DNA double helix are composed of the pentose sugar deoxyribose alternating with phosphate groups held together with special ester links i.e phosphodiester bonds.