Carbohydrates-Definition, Classification, Structures, Sources, Importance, FAQs

What is Biomolecule ?

In this article, we will learn in detail about carbohydrates, its classification, sources, and its importance.

What are Carbohydrates?

In a human body the cells are depended on on the glucose for fuel. Carbohydrates plays an important role in providing the glucose to the cells in human body so that it can function properly. Carbon, hydrogen, and oxygen are the three components that make up carbohydrate biomolecules. (CH2O)n is the typical empirical formula for carbohydrates. They are one of the vital dietary nutrients since they provide our bodies with quick energy.

Classification of Carbohydrates

Based on their structures, carbohydrates are divided into monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

  • Monosaccharides –Simple sugars with a free ketone or aldehyde group are known as monosaccharides. They can’t be hydrolyzed anymore because they’re the simplest of sugars. CnH2nOn or Cn (H2O) n is their chemical formula. Depending on their ketone or aldehyde group, monosaccharides are categorised as tiroses, tertroses, pentoses, and so on, as well as ketoses or aldoses. Glucose, fructose, galactose, glycerose, ribose, and ribulose are among examples.
A biomolecule, sometimes known as a biological molecule, is a word that refers to molecules found in living things that are required for one or more biological processes, such as cell division, morphogenesis, or development. Large macromolecules (or polyanions) like proteins, carbohydrates, lipids, and nucleic acids, as well as tiny molecules like primary metabolites, secondary metabolites, and natural products, are all examples of biomolecules.

Structure of Glucose

A biomolecule, sometimes known as a biological molecule, is a word that refers to molecules found in living things that are required for one or more biological processes, such as cell division, morphogenesis, or development. Large macromolecules (or polyanions) like proteins, carbohydrates, lipids, and nucleic acids, as well as tiny molecules like primary metabolites, secondary metabolites, and natural products, are all examples of biomolecules.

Structure of Fructose

  • Disaccharides – Disaccharides hydrolyze into two molecules of the same or distinct monosaccharides. The oxide bond, which is generated by the loss of a water molecule, connects the two monosaccharide units, and this linkage is known as glycosidic linkage. Sucrose is a typical disaccharide that breaks down into glucose and fructose when hydrolyzed. The other two main disaccharides are maltose and lactose (commonly known as milk sugar). There are two α-D-glucose in maltose and two β-D-glucose in lactose that are joined by an oxide bond.
A biomolecule, sometimes known as a biological molecule, is a word that refers to molecules found in living things that are required for one or more biological processes, such as cell division, morphogenesis, or development. Large macromolecules (or polyanions) like proteins, carbohydrates, lipids, and nucleic acids, as well as tiny molecules like primary metabolites, secondary metabolites, and natural products, are all examples of biomolecules.
  • Oligosaccharides – When sugars are hydrolyzed, they break down into two to ten molecules of monosaccharides. A disaccharide is an oligosaccharide that breaks down into two monosaccharide molecules upon hydrolysis, whereas trisaccharides, tetrasaccharides, and so on are oligosaccharides that break down into three or four monosaccharide molecules. Disaccharides have the chemical formula Cn (H2O)n-1, whereas trisaccharides and others have the chemical formula Cn (H2O)n-2, and so on. Sucrose, maltose, lactose, raffinose, and stachyose are examples of oligosaccharides.
  • Polysaccharides – Long monosaccharide molecules are linked together by a glycosidic linkage to form polysaccharides. The majority of them, such as Starch, serve as food storage. Plants use starch as their primary storage polysaccharide. It is a glucose polymer made up of two components: Amylose and Amylopectin. Cellulose is one of the most common polysaccharides found in plants. It is made up of β-D-glucose units linked together by a glycosidic bond between C1 of one glucose unit and C4 of the next.
A biomolecule, sometimes known as a biological molecule, is a word that refers to molecules found in living things that are required for one or more biological processes, such as cell division, morphogenesis, or development. Large macromolecules (or polyanions) like proteins, carbohydrates, lipids, and nucleic acids, as well as tiny molecules like primary metabolites, secondary metabolites, and natural products, are all examples of biomolecules.
  • Starch- Starch is a carbohydrate that plants store as an energy source. Amylose and amylopectin are two forms of polymeric chains found in them. Amylopectin has a branching structure with α1–4 and α1–6 glycosidic linkages, whereas amylose has a linear structure with α1–4 glycosidic links.
A biomolecule, sometimes known as a biological molecule, is a word that refers to molecules found in living things that are required for one or more biological processes, such as cell division, morphogenesis, or development. Large macromolecules (or polyanions) like proteins, carbohydrates, lipids, and nucleic acids, as well as tiny molecules like primary metabolites, secondary metabolites, and natural products, are all examples of biomolecules.

Functions of Carbohydrates

  • Carbohydrates are the major or principal energy sources in our bodies.
  • They have a role in fat metabolism as well.
  • Carbohydrates keep you out of ketosis.
  • This is a kind of connective tissue.
  • Carbohydrates keep the body’s digestive system running smoothly.
  • Carbohydrate fibers can help reduce blood cholesterol levels.
  • Because carbohydrates prevent protein from being burnt, they are needed to construct and repair.
  • Carbohydrates provide the central nervous system with energy.
  • They come in a variety of forms, including sugar, glucose, starch, and fiber.

Sources of Carbohydrates

  • Many fruits contain simple sugars in the form of fructose.
  • All dairy products include galactose.
  • Lactose may be found in large quantities in milk and other dairy products.
  • Maltose may be found in a variety of foods, including cereal, beer, potatoes, processed cheese, and pasta.
  • Sucrose is derived from sugar and honey, both of which include trace quantities of vitamins and minerals.

Carbohydrate Foods

Nutrients are the compounds found in food that supply us with energy for development and repair. Carbohydrates may be found in both healthy and unhealthy food. They can be found in a variety of forms, including sugars, starch, and fibres.

Carbohydrates in healthy food consist of both animal and plant sources which include:

  • Corn
  • Potatoes
  • Milk Products
  • Fresh Fruits
  • Vegetables

Carbohydrates in Unhealthy food includes:

  • White Bread
  • Artificial Sugar
  • Pastries
  • Soda
  • Other Highly Processed Foods

Importance of Carbohydrates

  1. Carbohydrates aid in metabolism and provide our bodies with energy in the form of glucose.
  2. Plant cells are made up of the disaccharide cellulose. Plant cellulose is also utilised in the production of papers, textiles, and wood for building.
  3. Photosynthesis, which manages the oxygen and carbon dioxide gas balance among plants and animals, is one of the most important processes in our biosphere. Plants utilise sunlight and carbon dioxide to release oxygen into the atmosphere, while glucose is generated and stored as a type of energy in plants. When animals eat plants, they acquire energy from the stored carbohydrate, and we may survive as a result.
  4. Carbohydrates play an important role in our diet since they are one of our body’s main sources of energy.
  5. Plants store starch, which includes thousands of glucose units, as an energy source.
  6. Glycogen is a complex carbohydrate stored in animal cells that breaks down into simple glucose molecules during stress and muscle exercise.
  7. Arthropods’ exoskeletons are composed of chitin, a complex carbohydrate.

Importance of Carbohydrates in Human Body

Our brain, heart, kidneys, and central nervous system all run on carbohydrates. Carbohydrates, along with lipids and proteins, are an important part of our diet. Our bodies convert carbs in meals to glucose, which gives us energy.

When the body eats too many carbs, it stores them in the liver cells as glycogen, a complex carbohydrate. Despite the fact that glucose is essential for delivering energy to our bodies, our blood sugar levels must be controlled in order to avoid significant health problems such as diabetes. Insulin is a hormone produced by the pancreas that lowers blood sugar levels and stores them as fat in the liver and muscles.

Importance of Carbohydrates in all Living Organisms

  • Carbohydrates are necessary for all living things in our environment to survive. They are all organisms major sources of energy.
  • Sugar molecules such as ribose and deoxyribose make up the majority of genetic materials (DNA and RNA) in living organisms. The polymer’s backbone is a sugar-phosphate-sugar chain, which forms a helical shape.
  • ATP (Adenosine Triphosphate), the most important energy-transfer molecule in living beings, is also made from ribose sugar, a carbohydrate.
  • Green plants convert carbon dioxide into organic substances such as sugars, which supply energy to the plants.
  • In the soil, certain carbohydrates enhance seed germination and root elongation.
  • Some rare sugars are employed in the pharmaceutical sector to make blood sugar-controlling medications.
  • Anti-inflammatory properties of some complex oligosaccharides and oligonucleotides aid in the treatment of cancer.
  • Antiviral medicines containing nucleoside analogues of uncommon sugars are used to treat HIV and HCV.

Importance of Carbohydrates in Our Diet

Carbohydrates are a rich source of vitamins, minerals, and nutrients, as well as providing energy to our bodies. They give immediate energy in the form of glucose, which is our body’s major source of energy and may be stored. These carbs should be included in our diet in the form of bread, potatoes, fibers, fruits, vegetables, and whole grains.

Importance of Carbohydrates for Athletes

  • Energy- Carbohydrates are broken down into glucose molecules, which are stored in the liver and muscles and utilised later while exercising. Carbohydrates provide the majority of the energy that our minds and bodies require to perform correctly. Fatigue is postponed as a result of the existence of a sufficient quantity of carbohydrates in the body, which increases athletic performance.
  • Increase in Muscle Mass- To grow muscle, a sufficient amount of protein is essential. When the body’s glucose consumption is high yet there isn’t enough stored, the body begins to break down proteins to fulfil its energy needs.
  • Protein can aid in the free repair and rebuilding of muscle tissue if enough carbs are supplied to muscles, which maximises muscular development. A balanced diet rich in carbs such as grains, wheat, yoghurt, milk, fruits, vegetables, juices, and other fruits and vegetables is essential for athletes to maintain their performance and muscular potential.

Carbohydrates- FAQs

What is the importance of carbohydrates in nutrition?

Carbohydrates are essential for good nutrition since they provide energy to our bodies. Vitamins, minerals, and nutrients are abundant in them. They give immediate energy in the form of glucose, which is a major energy source that may be stored. These carbs should be included in our diet in the form of bread, potatoes, fibres, fruits, vegetables, and whole grains.

What is the importance of carbohydrates in living organisms?

Carbohydrates are necessary for all living things in our environment to survive. They are all organisms’ major source of energy. They aid in the production of genetic materials, as well as plant and animal cell architecture. Green plants make them and utilise them as energy in the form of ATP.

What is the importance of carbohydrates in energy consumption?

Carbohydrates are our bodies’ most efficient energy source. Our brain, heart, and other critical organs of our body get this energy, which gives them potential.

What is the function of carbohydrates?

Carbohydrates serve a variety of purposes in the body, including storing energy, providing energy for important tasks, regulating blood sugar, and supplementing fats and proteins for other purposes.

What is starch?

Starch is a kind of carbohydrate that plants use to store energy. It contains two types of polymeric chains: amylose and amylopectin. Amylopectin has a branching structure with glycosidic connections α1–4 and α1–6, whereas amylose has a linear structure with α1–4 glycosidic linkages.

What is monosaccharide?

It is a kind of carbohydrate with only one sugar molecule in it. Hydrolysis cannot break them down into smaller sugar molecules. Glucose, fructose, and galactose are examples of monosaccharides.

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.

CBSE Class 12 Chemistry Syllabus Download PDF

Below is the CBSE Class 12 Syllabus along with the marking scheme and time duration of the Chemistry exam.

S.NoTitleNo. of PeriodsMarks
1Solutions107
2Electrochemistry129
3Chemical Kinetics107
4d -and f -Block Elements127
5Coordination Compounds127
6Haloalkanes and Haloarenes106
7Alcohols, Phenols and Ethers106
8Aldehydes, Ketones and Carboxylic Acids108
9Amines106
10Biomolecules127
Total70

CBSE Class 12 Chemistry Practical Syllabus along with Marking Scheme

The following is a breakdown of the marks for practical, project work, class records, and viva. The total number of marks for all parts is 15. The marks for both terms are provided in the table below.

Evaluation Scheme for ExaminationMarks
Volumetric Analysis08
Salt Analysis08
Content-Based Experiment06
Project Work and Viva04
Class record and Viva04
Total30

CBSE Class 12 Chemistry Syllabus (Chapter-wise)

Unit -1: Solutions

  • Raoult's law.
  • Colligative properties - relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, osmotic pressure, determination of molecular masses using colligative properties, abnormal molecular mass.
  • Solutions, Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases in liquids, solid solutions.
  • Van't Hoff factor.

Unit -2: Electrochemistry

  • Redox reactions, EMF of a cell, standard electrode potential
  • Nernst equation and its application to chemical cells
  • Relation between Gibbs energy change and EMF of a cell
  • Kohlrausch's Law
  • Electrolysis and law of electrolysis (elementary idea)
  • Dry cell-electrolytic cells and Galvanic cells
  • Conductance in electrolytic solutions, specific and molar conductivity, variations of conductivity with concentration.
  • Lead accumulator
  • Fuel cells

Unit -3: Chemical Kinetics

  • Rate of a reaction (Average and instantaneous)
  • Rate law and specific rate constant
  • Integrated rate equations and half-life (only for zerfirst-order order reactions)
  • Concept of collision theory (elementary idea, no mathematical treatment)
  • Factors affecting rate of reaction: concentration, temperature, catalyst;
  • Order and molecularity of a reaction
  • Activation energy
  • Arrhenius equation

Unit -4: d and f Block Elements  

  • Lanthanoids- Electronic configuration, oxidation states, chemical reactivity and lanthanoid contraction and its consequences.
  • Actinoids- Electronic configuration, oxidation states and comparison with lanthanoids.
  • General introduction, electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first-row transition metals – metallic character, ionization enthalpy, oxidation states, ionic radii, color, catalytic property, magnetic properties, interstitial compounds, alloy formation, preparation and properties of K2Cr2O7 and KMnO4.

Unit -5: Coordination Compounds  

  • Coordination compounds - Introduction, ligands, coordination number, color, magnetic properties and shapes
  • The importance of coordination compounds (in qualitative analysis, extraction of metals and biological system).
  • IUPAC nomenclature of mononuclear coordination compounds.
  • Bonding
  • Werner's theory, VBT, and CFT; structure and stereoisomerism

Unit -6: Haloalkanes and Haloarenes  

  • Haloarenes: Nature of C–X bond, substitution reactions (Directive influence of halogen in monosubstituted compounds only). Uses and environmental effects of - dichloromethane, trichloro methane, tetrachloromethane, iodoform, freons, DDT.
  • Haloalkanes: Nomenclature, nature of C–X bond, physical and chemical properties, optical rotation mechanism of substitution reactions.

Unit -7: Alcohols, Phenols and Ethers   

  • Phenols: Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophilic substitution reactions, uses of phenols.
  • Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses.
  • Alcohols: Nomenclature, methods of preparation, physical and chemical properties (of primary alcohols only), identification of primary, secondary and tertiary alcohols, mechanism of dehydration, and uses with special reference to methanol and ethanol.

Unit -8: Aldehydes, Ketones and Carboxylic Acids   

  • Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses.
  • Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation, physical and chemical properties, mechanism of nucleophilic addition, the reactivity of alpha hydrogen in aldehydes, uses.

Unit -9: Amines    

  • Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry.
  • Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, and identification of primary, secondary and tertiary amines.

Unit -10: Biomolecules     

  • Proteins -Elementary idea of - amino acids, peptide bond, polypeptides, proteins, structure of proteins - primary, secondary, tertiary structure and quaternary structures (qualitative idea only), denaturation of proteins; enzymes. Hormones - Elementary idea excluding structure.
  • Vitamins - Classification and functions.
  • Carbohydrates - Classification (aldoses and ketoses), monosaccharides (glucose and fructose), D-L configuration oligosaccharides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen); Importance of carbohydrates.
  • Nucleic Acids: DNA and RNA.

The syllabus is divided into three parts: Part A, Part B, and Part C. Part A consist of Basic Concepts of Chemistry, which covers topics such as atomic structure, chemical bonding, states of matter, and thermochemistry. Part B consists of Topics in Physical Chemistry, which includes topics such as chemical kinetics, equilibrium, and electrochemistry. Part C consists of Topics in Organic Chemistry, which covers topics such as alkanes, alkenes, alkynes, and aromatic compounds.

Basic Concepts of Chemistry:

  • Atomic structure: This section covers the fundamental concepts of atomic structure, including the electronic configuration of atoms, the Bohr model of the atom, and the wave nature of matter.
  • Chemical bonding: This section covers the different types of chemical bonds, including ionic, covalent, and metallic bonds, as well as the concept of hybridization.
  • States of the matter: This section covers the three states of matter - solid, liquid, and gas - and the factors that influence their properties.
  • Thermochemistry: This section covers the principles of thermochemistry, including the laws of thermodynamics and the concept of enthalpy.

Chapters in Physical Chemistry:

  • Chemical kinetics: This section covers the study of the rate of chemical reactions and the factors that influence it, including the concentration of reactants, temperature, and the presence of catalysts.
  • Equilibrium: This section covers the principles of chemical equilibrium, including the concept of Le Chatelier's principle and the equilibrium constant.
  • Electrochemistry: This section covers the principles of electrochemistry, including the concept of half-cell reactions, galvanic cells, and electrolysis.

Chapters in Organic Chemistry:

  • Alkanes: This section covers the properties and reactions of alkanes, including their structure, isomerism, and combustion.
  • Alkenes: This section covers the properties and reactions of alkenes, including their structure, isomerism, and addition reactions.
  • Alkynes: This section covers the properties and reactions of alkynes, including their structure, isomerism, and addition reactions.
  • Aromatic compounds: This section covers the properties and reactions of aromatic compounds, including their structure, isomerism, and electrophilic substitution reactions.

In addition to the topics covered in the syllabus, the CBSE Class 12 Chemistry exam also tests students on their analytical and problem-solving skills, as well as their ability to apply the concepts learned in the classroom to real-world situations.

Students can also check out the Tips for the Class 12 Chemistry Exam. They can easily access the Class 12 study material in one place by visiting the CBSE Class 12 page at ANAND CLASSES (A School Of Competitions). Moreover, to get interactive lessons and study videos, download the ANAND CLASSES (A School Of Competitions) App.

Frequently Asked Questions on CBSE Class 12 Chemistry Syllabus

Q1

How many chapters are there in the CBSE Class 12 Chemistry as per the syllabus?

There are 10 chapters in the CBSE Class 12 Chemistry as per Syllabus. Students can learn all these chapters efficiently using the study materials provided at ANAND CLASSES (A School Of Competitions).

Q2

What is the marking scheme for CBSE Class 12 Chemistry practical exam according to the syllabus?

The marking scheme for CBSE Class 12 Chemistry practical exam, according to the syllabus, is 8 marks for volumetric analysis, 8 marks for salt analysis, 6 marks for the content-based experiment, 4 marks for the project and viva and 4 marks for class record and viva.

Q3

Which is the scoring chapter in Chemistry as per CBSE Class 12 syllabus?

The chapter Electrochemistry in Chemistry is the scoring chapter as per CBSE Class 12 syllabus.