Question

Which of the following biomolecules does have a phosphodiester bond?
A. Nucleic acids in nucleotide
B. Fatty acids in glyceride
C. Monosaccharides in polysaccharide
D. Amino acids in a polypeptide

Answer 1

Single moiety or simple biomolecules form a covalent bond, hydrogen bond, van der Waals bond among themselves and then forms complex biomolecules. These complex biomolecules have various metabolic and biochemical functions in the body and regulate various processes.

Complete answer: Option A) Nucleic acids are composed of a nitrogen base, a pentose ribose, or deoxygenated pentose ribose sugar. The nucleic acids without the phosphate group are called nucleosides and the one with the phosphate attachment is called nucleotides. The nitrogen bases are purines and pyrimidines: adenine, guanine, cytosine, thymine, and uracil. Uracil is absent in DNA but present in RNA. The phosphate group of one sugar moiety is attached to the hydroxyl group of other sugar in the 3’ to 5; direction. This is called the phosphodiester bond.
Option B) The glycerin or glycerol has three hydroxyl groups and can form an ester bond with the fatty acid by an oxygen atom and form monoglycerides, triglycerides, or triglycerides based on the number of bonds formed by fatty acid with glycerol.
Option C) Monosaccharides like glucose can form glycosidic bonds with the other glucose and form a disaccharide called maltose. A glycosidic bond is a condensation reaction where a water molecule is released in the bonding of two sugar moieties. Even starch, glycogen, cellulose are formed by the glycosidic bond between sugar molecules. The orientation of the sugar molecule in the plane-polarized light decides the nomenclature of the bond.
Amino acids have an amino and a carboxylic group along with hydrogen and an R group. The carboxylic group of one amino acid forms a bond with the amino group of another amino acid and a water molecule is released to form a peptide.

Hence, the correct answer is an option (A).

Note: The bond between phosphates of one sugar molecule with the hydroxyl group of others is called phosphodiester bond. It is different from the phosphodiester bond. The DNA being antiparallel has two strands of nucleotides joined by hydrogen bonds and the nucleotides in the same strand joined by a phosphodiester bond.