Biomolecules NEET Important Notes, Overview and Types

Biomolecules NEET Important Notes

Every organism comprises tiny building blocks called cells– the smallest fundamental unit of life. It consists of several organic and inorganic compounds. All carbon-containing substances present in living things are referred to as biomolecules.

Biomolecules are an important element of the NEET. These comprehensive Biomolecules NEET notes will give you a leg up in the competition.

Biomolecules: An Overview

These are the organic molecules produced by living organisms and act as a building block of life. It performs an important function in living organisms and is composed of carbon, hydrogen, oxygen, Sulphur, and phosphorous. Proteins, Nucleic acids, Lipids, and Carbohydrates are the most common biomolecules.

Types of Biomolecules

Biomolecules are categorized into four types:


  1. Sugars, glycogen (animal starch), plant starch, and cellulose are only a few examples.

  2. Carbohydrate source: mostly photosynthesis. It is found in just 1% of plants, yet it accounts for 80% of their dry weight.

  3. Composition: CnH2N is the ratio of carbon, hydrogen, and oxygen. Saccharide is another name for it, and sugars are the main constituents.

  4. Monosaccharide properties
  • Monosaccharides are solids that are colorless and sweet in taste.
  • They exist in distinct isomeric forms due to asymmetric carbon. They are dextrorotatory and laevorotatory because they can rotate polarised light.
  • D-glucose is converted to polyhydroxy alcohol, sorbitol, or mannitol the following reduction.
  • Cu++ is reduced to Cu+ by sugars having a free aldehyde or ketone group (cuprous to cupric).
  • Sugars undergo oxidation, esterification, and fermentation processes.
  • A simple sugar's aldehyde or ketone group can form a C-O-C bond with an alcoholic group of another organic molecule. Condensation (H-O-H) or H+OH H2O is a process that includes water loss.

Biomolecules for NEET are a vast topic. It requires a clear concept to answer the entire questions asked for this topic. If you are facing trouble understanding the topic, you can take our biology online tuition to boost your preparation.


  1. Berzelius created the term protein in 1838, and G. J. Mulder used it for the first time in 1840.

  2. Protein makes up 15% of protoplasm. The average protein has 16% nitrogen, 50–55% carbon, 20–24% oxygen, 7% hydrogen, and 0.3–0.5% sulphur. Small amounts of iron, phosphorus, copper, calcium, and iodine are also found.

  3. Protein structure: This is due to distinct amino acid rearrangements. A peptide bond is formed when the carboxyl group of one amino acid binds to the amino group (– NH2) of another amino acid. Dipeptides, tripe tides, and polypeptides are all types of peptides. Insulin is the most basic protein. Insulin is made up of 51 amino acids, according to Sanger (1953). A protein can have up to four conformation levels.
  • Primary structure: A protein's primary structure has its covalent linkages. It exclusively relates to the linear sequence, quantity, and type of amino acids linked by peptide bonds. Ribonuclease, insulin, hemoglobin, and soon.

  • Secondary structure: Secondary structure refers to folding a linear polypeptide chain into a certain coiled structure (- helix), and ß - pleated sheet refers to the structure with intermolecular hydrogen bonding. This helical structure may be observed in fur protein, hair claw keratin, and feather keratin. ß - silk fibres have a pleated structure.

  • Tertiary structure: Tertiary structure refers to the organization and linking of proteins into certain loops and bends. It is held together by hydrogen, ionic, hydrophobic, and disulfide bonds.

  • Quaternary structure: The protein is made up of the same units. Lactic dehydrogenase, for example, has a similar quaternary structure. Heterogeneous quaternary structure occurs when the units are diverse, such as hemoglobin, which has two - chains and two ß - chains.


Lipid Acid

  1. Bloor invented the term lipid.

  2. These are fatty acid and alcohol esters.

  3. They are hydrophobic and insoluble in water, whereas benzene, ether, and chloroform are soluble.

  4. Lipids are divided into three categories:–

    1. Simple lipids: These are fatty acid and glycerol esters. They are typed as follows:–

      1. Fats and Oils: (Natural lipids or true fats). These are fatty acid and glycerol triglycerides. Oils are fats that are liquid at normal temperatures. Polyunsaturated fatty acids, such as those found in sunflower oil, help to reduce blood cholesterol.

      2. Fatty acid: These are obtained from the fats by hydrolysis. Formic acid is considered the simplest formic acid and is of two types:

        1. Saturated fatty acid: It doesn't have a double bond between the carbon atoms, for example, butyric acid, palmitic acid, etc. These have certain characteristics such as high melting points, increased blood cholesterol, and solid at room temperature.

        2. Unsaturated fatty acid: It has a double bond between carbon atoms, for example, 8 hexadecanoic acid, 9 octadecanoic acids, etc. These have a lower melting point, mainly found in the plant flats, and lower blood cholesterols and liquid at room temperature.

      3. Wax: Simple lipids formed of long-chain fatty acid and long-chain monohydric alcohol. These are insoluble in water, have high melting points, and are resistant to atmospheric enzymes that do not digest because it is chemically inert. They function as an excellent lubricant and minimize the rate of transpiration by making plant tissue water-resistant.

  5. Compound lipids: These lipids contain an extra ingredient. Groups containing fatty acids and alcohol can be of the following sorts, depending on the group:


  1. Phospholipids: These are phospholipids that include phosphoric acid. It aids in transport, metabolism, blood coagulation, and cell membrane permeability. It is a bipolar molecule with the hydrophilic phosphate-containing end and the hydrophobic fatty acid molecules (non-polar tail).

  2. On the other hand, Glycolipids include nitrogen and glucose in addition to fatty acids. Generally present in the neurological system's white matter. For example, sesocine frenocin.

  3. Chromolipids: Include pigmented lipids.

Functions of Lipids

  • Work as a heat insulator
  • Use in the synthesis of the hormones
  • Protective in functions such as in plants, bacteria, vertebrates, and insects.

Nucleic Acids

  1. These are the polymers nucleotide composed of hydrogen, oxygen, carbon, nitrogen, and phosphorus, which control the cell's basic function.

  2. First reported in 1971 by Friedrich Miescher from the nucleus of a pus cell.

  3. For the first time, Altmann referred to it as nucleic acid.

  4. They are discovered in the nucleus. They help in the transmission of genetic data.

  5. Nucleic acid types: Nucleic acids are categorized into two categories based on nucleotides, including sugars, phosphates, and nitrogenous bases. These are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) (Ribonucleic acid).

    1. Genetic material (Deoxyribonucleic acids)

      1. DNA Types: Eukaryotes and prokaryotes have linear and circular DNA, respectively.

        1. Palindromic DNA: The DNA helix contains nucleotides in a serial sequence but two strands opposite each other.

        2. Repetitive DNA: This sort of organization is located near the chromosome's centromere and does not affect RNA production. The nitrogenous base sequence is repeated multiple times.

        3. Unsaturated fatty acid: It has a double bond between carbon atoms, for example, 8 hexadecanoic acid, 9 octadecanoic acids, etc. These have a lower melting point, mainly found in the plant flats, and lower blood cholesterols and liquid at room temperature.

      2. Satellite DNA: It has base pairs ranging from 11 to 60bp and is repetitive. They're utilized for things like DNA matching and fingerprinting (Jefferey). DNA is dextrorotatory in eukaryotes, and sugars have a pyranose structure.

    2. RNA (ribonucleic acid): RNA is a form of nucleic acid that may be found in both the nucleus and the cytoplasm, such as mitochondria, plastids, and ribosomes. Certain viruses convey genetic information. They are extensively dispersed throughout the cell.

Download Biomolecules NEET Notes PDF

Score High In Your Exam with These Biomolecules Notes for NEET

Once you have covered the entire syllabus, you need comprehensive last-minute revision notes that help you revise each topic. Make sure you test yourself through MCQs, sample test papers, short answer questions, previous year questions papers, and much more. Our online coaching for NEET Preparation will help you boost your exam preparation with exclusively designed study materials, comprehensive notes, sample papers, and much more. The following are the additional key benefits you can avail of:

  • Live solving previous year's question paper.
  • Regular mock test to discover your strength and weakness.
  • Proficient professionals
  • Affordable fee structure and much more.

Copyright © 2024 SSSI. All rights reserved.