Question

Compare and contrast each of the four organic macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids. Be sure to include the following:

1) Explain how dehydration synthesis and hydrolysis work.

2) What are the monomers of each of the 4 macromolecules?

3) What are the polymers of each of the 4 macromolecules?

4) Provide an example of each of the 4 macromolecules.

5) What kinds of bonds hold the monomers together to make a polymer? Name the 4 special bonds.

6) Give at least 2 functions of each kind of macromolecule.

7) Where can you find each macromolecule in a cell?

Answer 1

Carbohydrates: These sugars polymers made of glucose polymers. The synthesis of a long chain of polymers of carbohydrates is made by the glycosidic bond between the two glucose molecules or any other monosaccharide sugars like fructose, galactose etc. The polymers include cellulose, glycogen, starch etc. Carbohydrates are involved in the storage of energy and also important for the cell structure in plants. The carbohydrates are usually found in the cell cytoplasm where the glycolysis takes place.

Lipids: Lipids are made of basic units called fatty acids residues which upon polymerisation with other groups form structures called triglycerides. The excess of energy in the body is converted into triglycerides by synthesis of fatty acids from acetyl-CoA and esterification of fatty acids known as lipogenesis. The breakdown of fatty acids is called beta oxidation which releases acetyl-CoA molecules which enter the TCA cycle. The monomers are called as fatty acids and the polymers are known da glycerolipids, phosphoglycerolipids based on the group present. The best example of the lipids is cholesterol. The bonds involved in the polymerization of monomers to polymers include van der Waals and hydrogen bond. Lipids are involved in the cell signalling and the form an integral part of the cell membranes. The cell membrane is made up of the phospholipid bilayer.

Proteins: Proteins are made up of the basic monomer units called amino acids. The synthesis of long chain protein takes place by the dehydration reaction between two amino acids which are joined by the peptide bond. The example of the protein in the cell is Actin, which is the structural component of the cell. Proteins play a major role in the cell by performing the metabolic reaction in the form of enzymes and also form an important component of the cytoskeleton. Proteins are present everywhere in the cell.

Nucleic acids: These are biopolymers made up from the monomers called nucleotides which consist of a 5 carbon sugar, a phosphate group and nitrogenous base. The nucleic acids are joined together by phosphodiester bonds involving the sugar and the phosphate group. The polymers of the nucleic acids are called deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). They are involved in the storing the genetic information and also passing the information to many generations. The nucleic acids are found in nucleus of the cell.