Biomolecules and Polymers

Biomolecules are the most important organic molecules that are involved in living organisms’ maintenance and metabolic functions. Whereas, a polymer, also known as a macromolecule, is a big molecule made up of numerous subunits. Biomolecules and polymers play vital roles in the field of chemistry.

Biomolecules and its types

Biomolecules are those non-living molecules that are the true foot soldiers in the war for life’s survival. They range in size from small molecules like primary and secondary metabolites and hormones to massive macromolecules like proteins, nucleic acids, carbohydrates, lipids, and other macromolecules.

Carbohydrates, proteins, nucleic acids, and lipids are the four major classes of biomolecules. Each one is addressed further down.

Carbohydrates

Carbohydrates are polyhydroxy aldehydes or ketones, or substances that create them when they are hydrolyzed. In layman’s words, we refer to carbs as sugars or sweet-tasting compounds. Saccharides (Greek: sakcharon = sugar) are the collective name for them. Monosaccharides (1 unit), oligosaccharides (2-10 units), and polysaccharides are classified according to the number of constituent sugar units recovered after hydrolysis (more than 10 units). They serve a variety of purposes: they are the most abundant dietary source of energy; they are structurally vital for many living species as a primary structural component, for example, cellulose is an important structural fibre for plants.

Proteins

Proteins, which make up around half of the dry weight of a cell, are another class of essential macromolecules. Proteins are polypeptide chains made up of amino acids organized in a specific order. In some circumstances, the structure of proteins is classed as primary, secondary, tertiary, or quaternary. These structures are based on the degree of intricacy of a polypeptide chain’s folding. Proteins have structural and dynamic functions. Myosin is a protein that allows muscles to contract and move. Proteinaceous enzymes make up the majority of enzymes.

Nucleic acids

Nucleic acids are the genetic materials found in cells that carry all of the information passed down from parents to offspring. Nucleic acids are divided into two types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) (RNA). The transfer of genetic information and the creation of proteins are the primary functions of nucleic acid, which are accomplished through the processes of translation and transcription. The nucleotide is a monomeric unit of nucleic acids that consists of a nitrogenous base, pentose sugar, and phosphate. The nucleotide is distinguished by the nitrogen base linked to the pentose sugar. Adenine, guanine, cytosine, and thymine are the four primary nitrogenous bases found in DNA. Thymine is replaced by uracil in RNA.

The double-helix or double-helical structure of DNA is generated by hydrogen bonding between the bases of two antiparallel polynucleotide strands. The DNA structure resembles a twisted ladder in appearance.

Lipids

Lipids are organic compounds that are soluble in organic solvents but insoluble in water, are connected to fatty acids, and are used by living cells. Fats, waxes, sterols, fat-soluble vitamins, mono-, di-, or triglycerides, phospholipids, and other lipids are among them. Lipids are not polymeric compounds like carbohydrates, proteins, or nucleic acids. Lipids are the primary source of energy and play an important role in cellular structure.

Polymers and their types

Polymer is a Greek word that means ‘many components.’ Polymers can be found in almost every environment. From our DNA strand, which is a naturally occurring biopolymer, to polypropylene, which is utilized as a plastic all over the world.

Polymers can be found naturally in plants and animals (natural polymers) or they can be created artificially (synthetic polymers). Polymers contain a variety of physical and chemical qualities that allow them to be used in everyday life.

Polymers are difficult to categorize due to their complicated structures, diverse behaviors, and wide range of applications. As a result, we may classify polymers based on the following criteria.

Polymer classification based on the source of availability

Natural, synthetic, and semi-synthetic polymers are the three types of polymers included in this category.

Polymers derived from nature: They are found in both plants and animals and exist naturally. Proteins, starch, cellulose, and rubber, for example. To round things off, there are biopolymers, which are biodegradable polymers.

Polymers that are semi-synthetic: They are made from naturally existing polymers that have been chemically modified. cellulose nitrate and cellulose acetate, for example.

Synthetic polymers: Man-made polymers are known as synthetic polymers. The most prevalent and commonly used synthetic polymer is plastic. It’s used in a variety of industries and dairy products. 

Polymers classified depending on the structure of the monomer chain

The following classes apply to this category:

Polymers with a linear structure: Polymers with long and straight chains fall under this category. PVC, or polyvinyl chloride, is a linear polymer that is commonly used to make pipes and electric lines.

Polymers with Branched Chains: When a polymer’s linear chains produce branches, the polymer is classified as branched chain polymer. Low-density polythene, for example.

Polymers that are cross-linked: They are made up of monomers with bifunctional and trifunctional functions. In comparison to other linear polymers, they have a stronger covalent bond. Bakelite and melamine are both examples of this type of material.

Other Polymer Classification Methods

Polymerization-based classification.

Addition Polymerization: 

When the monomers are consumed totally and no byproducts are formed, this is termed as addition polymerization.

Polyethene, Teflon, and Polyvinyl chloride (PVC) are just a few examples.

Condensation polymerization: 

The reaction of monomers or oligomers with each other to form a larger structural units, forming a byproduct as smaller molecules such as water.

Nylon -6, 6, perylene, and polyesters are examples.

Monomer-Based Classification

Homomer: There is only one sort of monomer unit in this category. 

Heteropolymer or co-polymer: It is made up of a variety of monomer units. Nylon -6, 6 is an example.

Molecular Forces-Based Classification

Elastomers: Weak interaction forces exist in these rubber-like substances. Rubber, for example.

Fibres: These are strong, robust, have a high tensile strength, and have significant interaction forces. Nylon -6, for example.

Thermoplastics: These materials exhibit intermediate attraction forces. Polyvinyl chloride, for example.

Thermosetting polymers: These polymers significantly increase the mechanical characteristics of the material. It has improved chemical and thermal resistance. Phenolics, epoxies, and silicones, for example.

Polymerization Reactions Types

Polymerization by addition: Chain growth polymerization is another name for this process. Small monomer units link together to produce a massive polymer. The chain length grows longer with each step. Polymerization of ethane in the presence of peroxides, for example.

Polymerization via Condensation: Small molecules such as H2O, CO, and NH3 are removed during polymerization in this kind (step growth polymerization). This sort of polymerization reaction occurs most commonly in organic compounds with bifunctional groups, such as diols, -dials, diamines, and dicarboxylic acids. Preparation of nylon -6, for example.

Conclusion

Biomolecules are involved in the metabolic process of living organisms. Biomolecules play an important role in life by preventing various diseases. Ranging from small molecules like hormones to larger molecules like nucleic acids, biomolecules are present. Depending on the characteristics various types of biomolecules are defined such as Carbohydrates, proteins, nucleic acids and lipids.