Question

Explain the biomolecules building blocks of life.

Answer 1

The building blocks of life are carbohydrates, lipids, proteins and nucleic acids.

• Carbohydrates: 

1. Carbohydrates are biomolecules made from carbon, hydrogen and oxygen.
2. The general formula of carbohydrates is (CH₂O) n.
3. They contain hydrogen and oxygen in the same ratio as in water (2:1).
4. Carbohydrates can be broken down to release energy.
5. Based on sugar units, carbohydrates are classified into three types: Monosaccharides, disaccharides and polysaccharides.

• Lipids:

1. These are group of substances with greasy consistency with long hydrocarbon chains containing carbon, hydrogen and oxygen.
2. In lipids hydrogen to oxygen ratio is greater than 2:1.
3. Lipid is a broader term used for fatty acids and their derivatives.
4. They are soluble in organic solvents (non-polar solvents).
5. Fatty acids are organic acids which are composed of hydrocarbon chain ending in carboxyl group (COOH).
6. These are divided into: Saturated fatty acids and unsaturated fatty acids.
7. Fatty acids are basic molecules which form different kinds of lipids.
8. Lipids are classified into three types: Simple lipids, Compound lipids, Derived lipids.

• Proteins:

1. Proteins are large molecules containing amino acid units ranging from 100 to 3000.
2. They have higher molecular weight.
3. In proteins, amino acids are linked together by peptide bonds which join the carboxyl group of one amino acid residue to the amino group of another residue.
4. A protein molecule consists of one or more polypeptide chains.
5. Proteins contain any or all twenty naturally occurring amino acid types.
6. Proteins have different structures like primary structure, secondary structure, tertiary structure and quaternary structure.
7. Proteins are classified into three types:
   Simple proteins: Simple proteins on hydrolysis yield only amino acids. E.g. Histones and albumins.
   Conjugated proteins: It consists of a simple protein united with some non-protein substance. E.g. Haemoglobin.
   Derived proteins: These proteins are not found in nature as such but are derived from native protein molecules on hydrolysis. E.g. Metaproteins, peptones.

• Nucleic Acids:

1. Nucleic acids are macromolecules composed of many small units or monomers called nucleotides.
2. Each nucleotide is formed of three components i.e. pentose sugar, a nitrogen base and a phosphate (phosphoric acid).
3. When sugar combines with a nitrogenous base it forms nucleoside. Nucleotides can be called as nucleoside phosphate.
4. There are two types of nucleic acids, i.e. DNA and RNA. DNA (Deoxyribonucleic acid) is the genetic material of a cell. It is a double-stranded helix. Each strand of helix is made up of deoxyribose nucleotides. RNA (Ribonucleic Acid) is a single-stranded structure having fewer nucleotides as compared to DNA. The strands may be straight or variously folded upon itself. It is made up of nucleotides.