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Ncert Solutions for Class 12 Chemistry Chapter 14_30.1

Ncert Solutions for Class 12 Chemistry Chapter 14 in English

Class 12 Chemistry NCERT Solutions: Adda247 provides NCERT Solutions for Class 12 Chemistry Chapter 14. The NCERT Solutions provided here will enhance the concepts of the students, as well as suggest alternative methods to solve particular problems to the teachers.

NCERT Solutions are drafted by the faculty at Adda247 to help students learn all the complex concepts efficiently. NCERT Textbooks are answered in a systematic format to help the students learn in a shorter duration. These solutions are tailored by vast research to make it easier for the students to complete the whole syllabus before board exams. A lot of materials are available online but it is very important for the students to understand their needs and find it accordingly. For this purpose, we at Adda247 provided both online and offline format of the solutions completely based on the latest syllabus of the CBSE board.

Chemistry NCERT Solutions Class 12 includes a number of topics that offers students an in-depth knowledge of different aspects of Chemistry. To distinguish the equations and chemical formulas, after solving the NCERT chemistry class 12 PDF can be handy. The solution provided by Adaa247 is available in easily downloaded format.

You can refer to the chemistry class 12 solutions for better solutions and score good marks in board as well as competitive exams.

Benefits of Solutions of NCERT class 12 Chemistry:

  • NCERT Solutions for Class 12 is helpful to solve questions from other reference books too.
  • NCERT Solutions for Class 12 Chemistry will assist students to cross-check answers and prepare for the exams in a strategic way.

The students can access the solutions anywhere while browsing the web easily. The solutions are very precise and accurate.


NCERT Solution of Chemistry Class 12 Chapter 14: Biomolecules

NCERT includes chapters of biomolecules in the Class 12 board exams syllabus. Chapter 14 is elaborated in NCERT Solutions for Class 12 Chemistry and one of the most interesting chapters of the Class 12 syllabus.

It deals with the fact that all living beings are made up of non-living atoms and molecules. These molecules are referred to as Biomolecules. Class 12 Chemistry Chapter 14 NCERT Solutions deals with the subject of biomolecules in a very comprehensive manner and it gives a student a complete overview of the chapter and also a solution to all questions asked in the exercise.

Chapter 14 of the class 12 syllabus about Biomolecules deals with the complex subject of chemicals produced by a living organism to sustain life, promote growth and reproduce. It is an important part of the class 12 Chemistry syllabus as it is very basic of Biochemistry. Hence, it needs to be prepared well. NCERT Class 12 Chemistry Biomolecules PDF downloaded gives a complete overview regarding the Chapter.

Chapter 14 of the class 12 syllabus comprises the concept of Biomolecules. It explains that all living beings grow to sustain and reproduce. But all living organisms are made up of non-living atoms and molecules and all changes take place through a chemical reaction in a living organism. The NCERT Solutions of Biomolecules Class 12 give a comprehensive view of chemical change that goes on inside a living being.

Subtopics of chapter 14

  • Carbohydrates
  • Proteins
  • Enzymes
  • Vitamins
  • Nucleic acid
  • Hormones

An important aspect of Biomolecules Class 12 is the importance of Carbohydrates and proteins in our food.

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Key features of NCERT Solutions of Class 12 Chemistry Chapter 14

  • It provides a complete overview of the chapter.
  • Comes handy when revising.
  • The complex subject of Biomolecules is explained in simple language.
  • Clear doubts that may arise while going through the chapter.
  • Helps in preparation for not only board exams but also in other competitive exams.


Important questions of NCERT Solutions Chemistry Class 12 Chapter 14

1 What are monosaccharides?


Monosaccharides (from Greek monos: single, sacchar: sugar), also called simple sugars, are the simplest form of sugar and the most basic units (monomers) of carbohydrates.[1] The general formula is CnH2nOn,  albeit not all molecules fitting this formula (e.g. acetic acid) are carbohydrates. [2] They are usually colorless, water-soluble, and crystalline solids. Contrary to their name (sugars), only some monosaccharides have a sweet taste.

Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose and lactose) and polysaccharides (such as cellulose and starch). Each carbon atom that supports a hydroxyl group is chiral, except those at the end of the chain. This gives rise to a number of isomeric forms, all with the same chemical formula. For instance, galactose and glucose are both aldohexoses, but have different physical structures and chemical properties.

The monosaccharide glucose plays a pivotal role in metabolism, where the chemical energy is extracted through glycolysis and the citric acid cycle to provide energy to living organisms. Some other monosaccharides can be converted in the living organism to glucose.


2 What are reducing sugars?


Reducing sugars are carbohydrates that reduces Fehling’s solution and Tollen’s reagent. All monosaccharides and disaccharides, excluding sucrose, are reducing sugars.


3 Write two main functions of carbohydrates in plants.


The two main functions of carbohydrates in plants are:

i.)   Polysaccharides such as starch serve as storage molecules.

ii.) Cellulose, a polysaccharide, is used to build the cell wall.


4 Classify the following into monosaccharides and disaccharides.

  1. Ribose
  2. 2-deoxyribose

III. Maltose

  1. Galactose
  2. Fructose
  3. Lactose



Ribose, 2-deoxyribose, galactose, fructose.



Maltose, lactose.


5 What us glycogen? How is it different from starch.


Glycogen is a carbohydrate. In animals, carbohydrate are stored as glycogen. Starch is a carbohydrate consisting of two component – amylose and amylopectin. However, glycogen consists of only one component whose structure is similar is similar to amylopectin. Also, glycogen is more branched than amylopectin.


6 Enumerate the reactions of D-glucose which cannot be explained by its open chain structure.


(1) Aldehydes give 2, 4-DNP test, Schiff’s test, and react with NaHSO4to form the hydrogen sulphite addition product. However, glucose does not undergo these reactions.


(2) The pentaacetate of glucose does not react with hydroxylamine. This indicates that a free -CHO group is absent from glucose.


(3) Glucose exists in two crystalline forms – ∝ and β. The ∝-form (m.p. = 419 K) crystallises from a concentrated solution of glucose at 303 K and the β-form (m.p = 423 K) crystallises from a hot and saturated aqueous solution at 371 K. This behaviour cannot be explained by the open chain structure of glucose.


7 What are essential and non essential amino acids?  Give two examples of each type.


Essential amino acids are required by the human body, but they cannot by synthesized in the body. They must be taken though food. For example, valine and leucine. Non-essential.


8 Define the following as related to proteins:

  1. Peptide linkage
  2. Primary structure

III. Denaturation


(i)  A peptide linkage is an amide (—CO— NH —) linkage formed between —COOH group of one amino acid and —NH2 group of other a-amino acid by loss of a water molecule.

(ii) The specific sequence in which various a-amino acids present in a protein are linked to one another is called its primary structure. Any change in its primary structure creates a new protein.

(iii)Denaturation of Proteins: When a protein in its native form is subjected to a change, such as change in temperature or change in pH, the hydrogen bonds are disturbed. Due to this, globules unfold and helix get uncoiled and protein loses its biological activity. This is called denaturation of protein. During denaturation, 2° and 3° structures are destroyed but 1° structures remain intact, e.g., coagulation of egg while on boiling, curdling of milk, etc.


9 What are nucleic acids?  Mention their two important functions.


Nucleic acids are biomolecules found in the nuclei of all living cells, as one of the constituents of chromosomes. There are mainly two types of nucleic acids – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are also known as polynucleotides as they are long-chain polymers of nucleotides.

Two main functions of nucleic acids are:


(i) DNA is responsible for the transmission of inherent characters from one generation to the next. This process of transmission is called heredity.


(ii) Nucleic acids (both DNA and RNA) are responsible for protein synthesis in a cell. Even though the proteins are actually synthesised by the various RNA molecules in a cell, the message for the synthesis of a particular protein is present in DNA.


10 Differentiate between globular and fibrous proteins.


          Fibrous protein              Globular protein
It is fiber-like structure formed by the polypeptide chain. These proteins are held together by strong hydrogen and disulphide bonds. The polypeptide chain in this protein is folded around itself, giving rise to a spherical structure.
It is usually insoluble in water. It is usually soluble in water.
Fibrous proteins are usually used for structural purposes. For example, keratin is present in nails and hair, collagen in tendons, and myosin in muscles. All enzymes are globular proteins. Some hormones such as insulin are also globular proteins.



11 Write the important structural and functional difference between DNA and RNA.


The structural difference between DNA and RNA are as follows:

      DNA RNA
The sugar present in DNA molecules is -D-2-deoxyribose. The sugar present in RNA molecules is -D-ribose.
DNA contains thymine. It does not contain uracil. RNA contains uracil. It does not contain thymine.
The helical structure of DNA is double-stranded. The helical structure of RNA is single stranded.


The functional difference between DNA and RNA are as follows:

        DNA          RNA
DNA is the chemical basis of heredity. RNA is not responsible for heredity.
DNA molecules do not synthesize proteins, but transfer coded message for the synthesis of proteins in the cell. Proteins are synthesized by RNA molecules in the cells.


Frequently asked question on NCERT Solutions of Chemistry Chapter 14

  1. What are Biomolecules? What are the 4 main types of biomolecules?

Ans. The human body is composed of roughly 30 trillion cells that collectively perform the essential functions of life. The cells can perform these life-sustaining tasks with the help of several organic molecules present in them. These organic molecules are referred to as biomolecules.

The biomolecules have a wide range of sizes and structures, and they are involved in a vast array of life functions. They are composed of more than 25 naturally occurring elements, with the primary elements being carbon, hydrogen, oxygen, phosphorus, and sulphur. Carbon compounds have major involvement in the formation of biomolecules. They covalently bind with other elements to form several other compounds. Some biomolecules are considered derivatives of hydrocarbons, they’re formed by replacing hydrogen atoms from functional groups like alcohols, amines, aldehydes, ketones, and carboxylic groups.

The four major types of biomolecules are carbohydrates, lipids, nucleic acids, and proteins. Apart from these, there are various other biomolecules that are involved in carrying out the metabolic activities.


  1. What are monosaccharides?


  • Monosaccharides are simple sugars in which there are one oxygen atom and two hydrogen atoms for each carbon atom present in the molecule.
  • They have general formula as (CH2O)n.
  • Monosaccharides are reducing sugars.
  • The test for reducing sugar is called Benedict’s test.
  • They are sugars, which taste sweet, are soluble in water and are insoluble in non-polar solvents.
  • They exist in straight chains or in the ring or cyclic forms.
  • They are classified according to the number of carbon atoms in each molecule as trioses (3C), tetroses (4C), pentoses (5C), hexoses (6C), heptoses (7) and so on.
  • The names of all sugars end with -ose.
  • Examples: Glyceraldehyde (triose), Erythrose (tetrose), Ribose (pentose), Glucose (hexose), Fructose (hexose), Galactose (hexose), Sedoheptulose (heptose), etc.
  • They are used as a source of energy in respiration.
  • They are important building blocks for large molecules.


  1. What is the difference between glycogen and starch?

Ans. 1. Glycogen is made up of only one molecule while starch is made up of two.

  1. While both are polymers of glucose, glycogen is produced by animals and is known as animal starch while starch is produced by plants.
  2. Glycogen has a branched structure while starch has both chain and branched components.


  1. Are the NCERT Solutions for Class 12 Chemistry Chapter 14 on Adda247 reliable study resources?

Ans. Yes, the NCERT Solutions for Class 12 Chapter 14 Chemistry on Adda247 make very reliable study resources. These NCERT Solutions are prepared by our subject-matter experts, in accordance with the CBSE guidelines for Class 12. You can find the relevant chemical formulae and structures for every question, in these NCERT solutions. By going through these NCERT Solutions for Chapter 14 – Biomolecules, you will be able to revise all the key points covered in this chapter. So, download this PDF for free and refer to the best study guide for Biomolecules for you 12th board Chemistry examination.

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