5 Slides_Chemicals of Life_Proteins.pdf

CHEMICALS OF LIFE FAD1001 : BIOLOGY 1 Hazwani Mat Saad Academic Room (No.23) Level 3, PASUM Complex [email protected] Tel: 03-79675916  Contents ▪Introduction ✓Biomolecules definition ✓Elements, compounds ✓Important bonds in...

CHEMICALS OF LIFE FAD1001 : BIOLOGY 1 Hazwani Mat Saad Academic Room (No.23) Level 3, PASUM Complex [email protected] Tel: 03-79675916  Contents ▪Introduction ✓Biomolecules definition ✓Elements, compounds ✓Important bonds in biomolecules:- Ionic, covalent, hydrogen, van der Waals ▪Inorganic compounds : ✓ Structure, properties and functions ✓Acids, bases and buffers ✓Mineral salts ▪Organic compounds: carbohydrates, lipids, proteins, nucleic acids. ✓ Structure, properties and functions  PROTEIN Most diverse biomolecule Proteins structure Protein is a chain of amino acids (polypeptide) folded to become functional proteins ribosome assembles amino acids into proteins (polypeptide) cell builds diverse proteins from only 20 kinds of amino acids. Essential = need to obtain from diet Non-essential = body can synthesize the amino acids  Amino acid structure H Amino acids consist of:- An amino group (basic) A carboxyl group (acidic) Covalently bonded to A hydrogen atom the same C atom (asymmetric C) R group = side chains (one or more atoms) Properties of amino acid Determined by the “R‘Rgroup” group’ Amino acids may be: Nonpolar Polar Positively charged H Negatively charged Properties of amino acids Amino acids = amphoteric molecule Acidic and basic properties Can act as buffer buffer When dissolved in water, amino acids dissociates to form bipolar molecule zwitterions Basic Acidic  Zwitterions act as buffer In acidic condition, In basic condition, zwitterions will receive zwitterions will donate H at carboxyl group H from amino group  Polypeptide chain formation (Protein synthesis) Protein is a chain of amino acids linked by peptide Peptidebonds bond Peptide bond = a covalent bond Links amino group of one amino acid with carboxyl group of next amino acid Forms through condensation reaction Polypeptide chain formation Side chains Backbone Polypeptide chain formation Polypeptide chains has unique sequence of amino acids primary structure of protein Protein conformation Sequence of amino acids are determined by the gene (DNA) gene (DNA) Amino acids Amino acidssequence sequence determines a protein’s final shape/ functional shape/ protein conformation Protein needs to reach its conformation to be functional Polypeptide chains are folded into various levels of protein structure to reach their conformation Transported for use outside or within cell Levels of protein structure Primary Secondary Tertiary Quartenary Levels of protein structure Levels of protein structure Primary structure Unique sequence of amino acids of a polypeptide chain Sequence of amino acids are determined by DNA Slight change in primary structure can affect a protein’s conformation and its ability to function Levels of protein structure Secondary structure Regular, repeated folding of polypeptide chain Due to H bonds form between N – H group of one amino acid and C = O group of another Two types : -helix and - pleated sheet Levels of protein structure: secondary structure Levels of protein structure: secondary structure Hydrogen bond Levels of protein structure Tertiary structure Irregular folding of the polypeptide chain Due to 4 types of bonds between side chains R groups 1. Disulphide bonds (covalent bond) -Between 2 amino acids cysteine 2. Ionic bonds -Between charged R groups Hydrogen bonds 3. -Between polar R group 4. Hydrophobic and Van der Waals interactions -Between nonpolar R groups Levels of protein structure: Tertiary structure  Terms in chemical bonding Disulfide brides/disulfide bonds: Covalent bonds formed between the sulfur atoms of the two cysteine amino acids  Levels of protein structure: Tertiary structure Three-dimensional conformation of protein Function of a protein depends on its tertiary structure If destructed destructed it will loselose its its activity activity e.g. lysozyme, myoglobin Levels of protein structure Quarternary structure Interaction between more than one polypeptides in a single protein Collagen [3 polypeptides] Hemoglobin [4 polypeptides] (2 -chains and 2 -chains)  Classification of proteins Classification of protein based on structure Fibrous : Globular: spherical Long fibres or sheet https://ib.bioninja.com. Classification of protein: Based on structure Classification of proteins Classification of protein based on composition Conjugated: Simple : amino acids + Contain only non-protein group amino acids (prosthetic group) https://ib.bioninja.com. https://www.researchgate.net Classification of protein: Based on composition 1. Examples of simple proteins: albumin, globulin 2. Conjugated proteins Name of protein Prosthetic group Location Myoglobin Heme (contains iron) Muscles Haemoglobin Haem (contains iron) Erythrocytes Glycoprotein Carbohydrate Saliva Nucleoprotein Nucleic acid Chromosomes Ribosomes casein Phosphoric acid Milk Cytochrome Copper Electron carrier oxidase Roles of proteins Enzymes Hormones Receptors Roles of proteins https://www.youtube.com/watch?v=0U5J_unEM-Q Antibody Structural proteins Transport proteins Protein denaturation A process in which protein molecules lose its conformation (3D shape) Due to the bonds holding protein’s shape are broken Cause loss of biological function Most are irreversible irreversible Factors that are able to break bonds: extreme pH excessive heat organic solvents chemicals heavy metal ions Protein renaturation Using biotechnology methods, protein denaturation can be reversed i.e. protein refolding Only for simple proteins Renaturation – difficult / impossible with larger and complex proteins Protein denaturation vs protein renaturation https://web.njit.edu/~mitra/green_chemistry/EXP_3.htm Watch the video about proteins structures. Enjoy! https://www.youtube.com/watch?v=PPJ7C3hcnPw  1. Go this website 4. Enter class code: https://edpuzzle.com/ vibifno (Protein) 2. Sign up using siswa mail 3. Select your role (Student)  Watch the video and answer the questions Class code: vibifno https://edpuzzle.com/assignments/66aa72206f5a3ec3f2e77bbc/watch  Watch the video and answer the questions Class code: vibifno https://edpuzzle.com/assignments/66aa72a1a8fcddf0d405b088/watch  Watch the video and answer the questions Class code: vibifno https://edpuzzle.com/assignments/66aa731db9fc829bb1d6cc5a/watch  Watch the video and answer the questions Class code: vibifno https://edpuzzle.com/assignments/66aa73ad1fa4f0fd0fb3ed87/watch  Contents ▪Introduction ✓Biomolecules definition ✓Elements, compounds ✓Important bonds in biomolecules:- Ionic, covalent, hydrogen, van der Waals ▪Inorganic compounds : ✓ Structure, properties and functions ✓Acids, bases and buffers ✓Mineral salts ▪Organic compounds: carbohydrates, lipids, proteins, nucleic acids. ✓ Structure, properties and functions