A biomolecule, sometimes known as a biological molecule, is a term 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. Biological materials is a more broad term for this type of material. Biomolecules are essential components of living creatures. While endogenous biomolecules are created within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.
Table of Contents
What are Polysaccharides ?
Polysaccharides are linear or branched chains generated by connecting monosaccharide units with glycosidic connections. Polysaccharides, then, are monosaccharide polymers. Glycosidic linkages are used to connect the monosaccharide units.
Features of Polysaccharides
Glycans are a type of non-sugar.
Polysaccharides are biological compounds with a significant molecular weight.
Many of them are water-insoluble.
Polysaccharides do not have a sweet flavour.
Desiccation turns them into an amorphous powder.
Polysaccharides are polymers of simple sugars connected together by glycosidic linkages, which are covalent connections.
Polysaccharide terminal ends can be either reducing (the terminal carbon atom is not involved in the glycosidic link) or non-reducing (the terminal carbon atom is involved in the glycosidic bond) (terminal atom involved in glycosidic bond)
Polysaccharides have the general formula (C6H10O5)n, where n is the number of monosaccharide units and can range from 100 to 2500.
Types of Polysaccharides
Polysaccharides are polymers made up of monomeric units that might be of the same or distinct types. Polysaccharides are categorised as follows based on the sort of monosaccharide units that make them up:
Homopolysaccharides/Homoglycans: When the monomeric unit is only one type, such as starch, cellulose, glycogen, chitin, and so on.
Heteropolysaccharides/Heteroglycans: When the monomeric units have distinct types of monomers. Hyaluronic acid, gamma globulins, heparin, and other polysaccharides may contain lipid or protein components as well.
Polysaccharides can be categorised into the following categories based on their functional roles:
Storage polysaccharides: Which are used as food storage or reserve energy, such as starch and glycogen.
Structural polysaccharides: They primarily contribute to the creation of structural components of cells including cell walls, such as cellulose, hemicellulose, and lignin.
Examples of Polysaccharides
Starch
This is the most prevalent food storage polysaccharide discovered in plants.
Glucose, the photosynthetic end product, is transformed to starch and stored in various plant sections.
It’s a polymer made up of α–D- glucose subunits that comes in two varieties: amylose and amylopectin.
Amylose is an unbranched polymer made up of α–D– glucose subunits linked by α–1,4 glycosidic bonds.
An amylopectin is a branching form of starch in which the α–D– glucose subunits are joined by α–1,6 glycosidic bond.
Approximately every 20 to 30 glucose residues in the chain, branching emerges.
Amylase enzymes found in saliva and the small intestine rapidly hydrolyze starch.
Amylose is found in a coiled form in nature. It has gaps to accommodate the iodine molecules that form amylose-iodine complexes in this condition. These complexes are blue-black in colour, thus when starch is treated with iodine, it turns blue-black.
Cellulose
Another main polymer of β–D- glucose discovered in plants is this one.
It’s a fibrous, tough, and insoluble water polymer.
Glucose units are connected in a straight chain by β–1,4 glycosidic connections.
Hydrogen bonding occurs between the adjacent chains,
Resulting in a fibril with tensile strength.
Because humans lack the enzyme ‘cellulase,’ which breaks down the beta bonds in cellulose, they are unable to digest it.
Glycogen
In mammals, glycogen is the major storage polysaccharide.
Glycogen is similar to plant starch and is often referred to as animal starch.
Glycogen, like starch, is a polymer of glucose.
In straight chains, glucose units are joined by α–1,4 glycosidic links, while branching points are linked by α–1,6 glycosidic linkages.
The difference between starch and glycogen is that glycogen has a lot of branching in its chains.
The average length of the chain is 8-10 glucose residues.
Glycogen is largely stored in the liver and muscles in animals, while glycogenesis occurs primarily in the liver.
It functions as the animal body’s energy reserve.
Glycogen serves as a glucose storage facility in the body.
Hemicellulose
It’s a polysaccharide made up of a variety of sugars found in plants.
Hemicellulose contains glucose and acetyl derivatives of glucose.
Hemicellulose, like cellulose, is found in the plant cell wall and provides strength to the cells.
Inulin
Many plants generate inulin, which is a naturally occurring carbohydrate.
It’s a polymer made up of beta fructose residues linked by β–1,2 links.
Inulin is a storage polysaccharide found naturally in plants that do not retain starch.
Chicory root is the primary source of commercial inulin extraction.
Inulin is used in food manufacture as a sugar, fat, and wheat substitute, as well as in medicine to assess kidney function.
Inulin has antibacterial effects as well.
Chitin
Chitin is carbohydrate-containing nitrogen that is mostly found in arthropods and fungi.
A polymer made up of monomers of N-acetyl-D-glucosamine connected by a β–1,4 glycosidic bond.
It is a key component of the exoskeleton of insects such as beetles, bees, and cockroaches, as well as arthropod creatures such as crabs and prawns.
A significant component of the fungal cell wall is chitin.
Chitosan is a chitin derivative that is water-soluble.
Commercially, it’s employed as a biopesticide in agriculture and in winemaking. Because of its therapeutic characteristics, it is also employed in medicine.
Pectin
Pectin is a heteropolysaccharide found in plant cells’ cell walls.
Galacturonic acid, a galactose derivative, is the main component.
It’s found in plant cells’ primary and middle lamellae, as well as their cell walls.
Fruit fiber is also a source of this nutrient.
Commercially, pectin is utilised as a gelling ingredient in jams and jellies.
Pectin is used in wound healing as well as speciality medical adhesives.
Bacterial Polysaccharides
Bacterial polysaccharides are a group of polysaccharides and carbohydrate derivatives found in bacterial cell walls and membranes.
Peptidoglycans, lipopolysaccharides, and exopolysaccharides are examples of bacterial polysaccharides.
The main component of the bacterial cell wall is peptidoglycan.
Thick mucus-like polysaccharides secreted by pathogenic bacteria form a capsule-like structure around them.
Sample Questions(FAQs)
Question 1: What are Polysaccharides?
Answer:
Polysaccharides are linear or branching chains made up of monosaccharide units linked together by glycosidic bonds. Polysaccharides are polymers made up of monosaccharide monomers. The monosaccharide units are linked together using glycosidic bonds.
Question 2: What are the functions of polysaccharides?
Answer:
Polysaccharides have two purposes.
They are used by plants and animals to store food reserves.
They make up the structural components of living species’ bodies.
Question 3: What are the food sources of polysaccharides?
Answer:
Few examples of foods that are high in polysaccharides:
Tubers—Starch is found in potatoes, sweet potatoes, and tapioca.
Starch is found in seed grains such as rice, wheat, and maize.
Fruits contain pectin;
Polysaccharides are abundant in plant gums and resins.
Question 4: What are the examples of polysaccharides?
Answer:
Polysaccharides include cellulose, starch, glycogen, and chitin . In plants and animals, starch and glycogen are store polysaccharides, whereas cellulose and chitin are structural polysaccharides.
Question 5: What is Hemicellulose?
Answer:
It’s a polysaccharide composed of many sugars found in plants. Glucose and glucose acetyl derivatives are found in hemicellulose. Hemicellulose, like cellulose, is found in the cell wall of plants and gives them strength.
Neeraj Anand, Param Anand
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.
Below is the CBSE Class 12 Syllabus along with the marking scheme and time duration of the Chemistry exam.
S.No
Title
No. of Periods
Marks
1
Solutions
10
7
2
Electrochemistry
12
9
3
Chemical Kinetics
10
7
4
d -and f -Block Elements
12
7
5
Coordination Compounds
12
7
6
Haloalkanes and Haloarenes
10
6
7
Alcohols, Phenols and Ethers
10
6
8
Aldehydes, Ketones and Carboxylic Acids
10
8
9
Amines
10
6
10
Biomolecules
12
7
Total
70
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 Examination
Marks
Volumetric Analysis
08
Salt Analysis
08
Content-Based Experiment
06
Project Work and Viva
04
Class record and Viva
04
Total
30
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.
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