Very Good Quality Notes of Chemistry - Biomolecules - Proteins - Nucleic Acids - DNA & RNA, Study notes of Chemistry

Download Very Good Quality Notes of Chemistry - Biomolecules - Proteins - Nucleic Acids - DNA & RNA and more Study notes Chemistry in PDF only on Docsity! Biomolecules law ed ‘  What you already know What you will learn ● Amino Acids ● Classification of Amino Acids ● Physical Properties of Amino Acids ● Optical Activity of Alpha Amino Acids ● Structure and Classification of Proteins A to Z About the Protein Biomolecules ● Disaccharides (Sucrose, Maltose , Lactose ) ● Polysaccharides (Starch , Cellulose , Glycogen ) ● Importance of Carbohydrate ● Structure of 2-Deoxy-D-Glucose ● Introduction to Proteins Amino Acids Name of the amino acid Characteristic feature of side chain (R) Structure 3 letter symbol 1 letter symbol Valine ーCH(CH3)2 Val V Aspartic acid ーCH2ーCOOH Asp D Amino Acids Name of the amino acid Characteristic feature of side chain (R) Structure 3 letter symbol 1 letter symbol Glutamic acid ーCH2-CH2ー COOH Glu E Tyrosine ーCH2ーC6H4ー OH(p) Tyr Y Amino Acids Name of the amino acid Characteristic feature of side chain (R) Structure 3 letter symbol 1 letter symbol Lysine ー(CH2)4ーNH2 Lys K Serine ーCH2ーOH Ser S No. of carboxyl (-COOH) groups > No. of amino (-NH2) groups When, Acidic amino acids Classification of Amino Acids Aspartic acid Example -COOH group -NH2 group 2 1> Example -COOH group -NH2 group 2 1> Glutamic acid Classification of Amino Acids No. of carboxyl (-COOH) groups No. of amino (-NH2) groups When, = Neutral amino acids can be With non-polar side chain With polar side chain Neutral amino acids Classification of Amino Acids No. of carboxyl (-COOH) groups No. of amino (-NH2) groups When, < Basic amino acids Classification of Amino Acids Arginine -COOH group -NH2 group 1 2< Lysine Example -COOH group -NH2 group 1 2< Classification of Amino Acids As sticky As Glue Acidic Aspartic acid Glutamic acid A Short Trick! Classification of Amino Acids Solution Which of the following is a basic amino acid? a) Serine b) Alanine c) Tyrosine d) Lysine Lysine: No. of carboxyl (-COOH) group (1) < No. of amino (-NH2) group (2) Therefore, lysine is a basic amino acid. Serine, alanine and tyrosine are neutral amino acids. Hence, option (d) is the correct answer. Lysine On the basis of synthesis in body Non-essential amino acid Essential amino acid Classification of Amino Acids Essential Amino Acids Which cannot be synthesised in the body. To be obtained from diet Valine Lysine Example Physical properties Colour State Solubility Melting point Molecular behaviour Physical Properties of Amino Acids Physical Properties of Amino Acids Color Amino acids are usually colourless State Amino acids are Crystalline solids Amino acids are soluble in water Solubility Amino acids have very high melting points Glycine 233oC Example Melting point Physical Properties of Amino Acids Molecular behaviour Behave as salts Rather than simple amines or carboxylic acids 𝝰-Amino acid Can accept H+ Can donate H+ Do You Know? German word ——$§!|_ UKM SELLE ‘Hermaphrodite’ or ‘Hybrid’ a, Note! Zwitter ionic form Shows amphoteric behaviour Reacts with both acids and bases. Optical Activity of 𝝰-Amino Acids Chiral molecule Carbon attached to four different groups Since, single chiral carbon is present Hence, compound is optically active. No POS No COS Amino acids exist in ‘D’ and ‘L’ form Most naturally occurring amino acids have ‘L’ configuration D & L Configuration L-alanine D-alanine Example NH2 on the left NH2 on the right D & L Configuration Structure of Proteins Amino acid A Amino acid B Peptide bond Peptide bond is an amide formed between –COOH group and –NH2 group of an amino acid. Proteins are polymers of 𝝰-amino acids Glycylalanine (Gly-ala) Amino acid A Amino acid B Chemically amide Naming of Peptide Depending upon the number of amino acids reacting, the peptides can be dipeptide, tripeptide, tetrapeptide etc. Amino group of amino acid B Carboxylic group of amino acid A + _ Dipeptide Reaction Formation of Dipeptide Bond Glycine Alanine Glycylalanine (Gly-ala) + A Short trick! + Formation of Dipeptide Bond Point to Remember ! Polypeptide >Number of amino acids in polypeptide chain 10 Point to ! Proteins >Number of amino acids in polypeptide chain 100 Have molecular mass > 10000 u Do You Know? Insulin contains 51 amino acids. Which of the following structures represents the peptide chain? a) b) (peptide bond). Which statement is incorrect about peptide bond? c) C – N bond length in proteins is smaller than usual bond length of C – N bond. a) C – N bond length in proteins is longer than usual bond length of C – N bond. d) None of the above. b) Spectroscopic analysis shows planar structure of group. Solution Due to resonance, a double bond character is observed between carbon and nitrogen. Hence, bond length will be shorter. Hence, option (a) is the correct answer. Classification of Proteins Fibrous proteins Globular proteins Classification of proteins on the basis of molecular shape Asset Globular Protein When the chains of polypeptides coil around to give a spherical shape Usually soluble in water Examples: Insulin and albumin Albumins structure Primary Structure of Protein Each polypeptide in a protein has amino acids linked in a specific sequence Contains one or more polypeptide chains 1o structure of proteins Point to Remember! Any change in primary structure of proteins, i.e., sequence of amino acids, will create a different protein. Primary Structure of Protein Amino acid 1 Amino acid 2 Amino acid 3 Amino acid 4 N-Terminal of amino acid C-Terminal of amino acid Example + - 𝝰-Helix form Pleated form Keep Learning!