Amino Acids-Definition, Structure, Properties, Classification, FAQs Class 12 Chemistry

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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

What are Amino Acids ?

Structure of Amino Acids

Amino acids are the basic components of proteins. Organic substances containing both amino and carboxylic groups are known as amino acids.

Any carbon atom other than that of the carboxyl (–COOH) group may be linked to the amino group (–NH2).

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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Properties of Amino Acids

  • They are crystalline, colourless compounds.
  • Their melting point is really high.
  • The nature of the side chain influences the solubility in water.
  • They are amphoteric, which means they react with acids and bases.
  • Except for glycine, all have asymmetric carbon, which causes plane polarised light to rotate. Optical activity is the name for this feature.

Classification of Amino Acids

Classification Based on the Requirement of the Body:

  • Non-essential amino acids: These amino acids are produced by the body and do not need to be consumed. Out of the twenty amino acids, ten are non-essential. Glycine, alanine, serine, cysteine, glutamine, tyrosine, proline, aspartic acid, asparagine, and glutamic acid are amino acid.
  • Essential Amino Acids: These amino acids are not synthesised by the body and must be obtained from food. Out of the twenty amino acids, ten are non-essential. Valine, leucine, isoleucine, arginine, lysine, threonine, phenylalanine, tryptophan, and histidine are the amino acids that make up the human body. These essential amino acids are necessary for our bodies to grow, and a lack of them in our diet can lead to disorders like kwashiorkor.

Classification of Naturally Occurring Amino Acids: The naturally occurring amino acids can be classified into three groups: Aliphatic, Aromatic, and Heterocyclic amino acids.

Aliphatic Amino Acids

They are amino acids with a lengthy chain. Amino acids are further divided into the following categories:

  • Neutral Amino Acid:  Their molecules have an equal number of carboxylic and amino groups. Example: Glycine, alanine, valine, etc.
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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Glycine

  • Acidic Amino Acid: In their molecules, they have a higher proportion of carboxylic groups than amino groups. Example: Aspartic acid, glutamic acid which contains two –COOH groups and one –NH2 group.
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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Aspartic acid

  • Basic Amino Acid:  Its molecules have a higher proportion of amino groups than carboxylic groups. Example:  Lysine, arginine, and histidine, which contains two –NH2 groups and –COOH groups.
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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Lysine acid

  • Sulphur Containing Amino Acid: Its structure contains sulphydryl (–SH) groups. Example: Cysteine and Methionine
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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Methionine

Aromatic Amino Acid

They contain a benzene ring in their structure. Example: Phenylalanine and Tyrosine

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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Phenylalanine

Heterocyclic Amino Acids: 

They have a heterocyclic ring on their side chain with at least one element other than carbon. Example: Tryptophan, Proline, and Hydroxyproline

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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Proline

Some Common Amino Acids are:

S. No.α- Amino acidThree-letter abbreviation  One letter abbreviation  
1.GlycineGlyG
2.AlanineAlaA
3.ValineValV
4.LeucineLeuL
5.IsoleucineIleI
6.PhenylalaninePheF
7.MethionineMetM
8.TryptophanTrpW
9.ProlineProP
10.SerineSerS
11.CysteineCysC
12.AsparagineAsnN
13.GlutamineGlnQ
14.ThreonineThrT
15.TyrosineTyrY
16.Aspartic acidAspD
17.Glutamic acidGluE
18.LysineLysK
19.ArginineArgR
20.HistidineHisH

How is Protein Formed from Amino Acids?

The amino group of one amino acid molecule establishes a chemical connection with the carboxylic group of the other when they combine to make proteins. A peptide bond is the outcome of this process. This process of linking amino acids continues until all of the amino acids required for the synthesis of a protein have been linked together. Between the two amino acids, one water molecule is lost in this process. When two amino acids are joined in this way, a bigger unit known as a peptide is formed. A polypeptide is made up of many peptides that have been linked together. Polypeptides then join together to form a full protein.

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 organisms. While endogenous biomolecules are made within the organism, organisms typically require external biomolecules, such as specific nutrients, to exist.

Peptide bond

Role of Amino Acid in Our Body

  1. Amino acids are transformed into physiologically active molecules in a variety of ways. Tyrosine, for example, is transformed into the hormones thyroxine and adrenaline, as well as the skin pigment melanin.
  2. From the vitamin nicotinamide and the plant hormone indole acetic acid, glycine is involved in the synthesis of heme (haemoglobin protein) and tryptophan.
  3. Citrulline and ornithine are amino acids that are actively involved in the urea cycle in the liver, which helps to keep ammonia levels below hazardous levels.

Sample Questions (FAQs)

Question 1: Which foods contain amino acids?

Answer:

Animal and plant sources of amino acids are available. Amino acids can be found in grains, nuts, seeds, beans, legumes, fruits, vegetables, eggs, milk, cheese, fish, and seafood, among other foods.

Question 2: Is it safe to take amino acids every day?

Answer:

In general, using a small amount of amino acids every day is safe. A high dose of amino acids, on the other hand, is detrimental. They can cause stomach pain, diarrhoea, a dangerous drop in blood pressure, gastrointestinal distress, and other problems. 

Question 3: List 21 amino acids?

Answer:

Glycine, Alanine, Valine, Leucine, Isoleucine, Phenylalanine, Methionine, Tryptophan, Proline, Serine, Cysteine, Asparagine, Glutamine, Tyrosine, Aspartic acid, Glutamic acid, Lysine, Arginine, Histidine, and Selenocysteine are the 21 amino acids.

Question 4: Do amino acids have side effects?

Answer:

Excess amino acid consumption raises the risk of hypertension, heart illness, weariness, and contraction loss.

Question 5: What do amino acids do for your body?

Answer:

Proteins are nutrients that help you create muscle. Proteins are made up of amino acids, which are the basic building components. As a result, they aid in the growth and healing of the body’s damaged cells and tissues. Some amino acids, such as tyrosine, are transformed into physiologically active substances such as the hormones thyroxine and adrenaline, as well as the skin pigment melanin.

Question 6: Do amino acids affect kidneys?

Answer:

Citrulline and ornithine are two amino acids that are involved in the urea cycle in the liver. This contributes to keeping ammonia levels below dangerous levels.

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.