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Basic biological reactions

  1. Basic Biological Reactions Presented by : Meenakshi Das M.Sc. 1st Semester Department of Life Science and Bioinformatics Assam University, Silchar
  2. Introduction Living Organisms and Chemical reactions • Biological processes are the processes vital for a living organism to live. • Biological processes are made up of many chemical reactions that give rise to chemical transformation. • Metabolism is the example.
  3. Metabolism • Metabolism is the sum total of all the biochemical reactions. • Functions of metabolism are: 1. Synthesis of biomolecules. 2. Transport of ions and molecules across cell membranes. 3. Production of force and movement. 4. Removal of metabolic wastes and other toxic substances. Metabolism = Anabolism + Catabolism
  4. Biochemical Reactions • Chemical reactions associated with biological processes are of following main types: Neutralization Reaction Condensation Reaction Oxidation-Reduction Reaction Group transfer Reaction Hydrolysis Reaction Reactions involved in formation or removal of a double bond with group transfer Isomerization Reaction Reactions involved in single bond formation by eliminating the elements of water
  5. Biological Reactions and Enzymes ENZYME is a Biological CATALYST Enzyme speeds up a biological reaction by lowering activation energy Enzymes are not used up during a reaction and can be used over and over again Enzymes are proteinaceous in nature (except – Ribozyme)  Enzymatic reactions are reversible Enzymes are specific that is they control only one reaction
  6. Neutralization Reaction • It is the interaction of an acid and a base to form a salt and water. • This reaction is important for maintaining a constant pH in the body. • Buffers helps in maintaining pH.  It releases H+ ions when the fluid is too basic  It takes up H+ ions when fluid is too acidic
  7. Carbonic acid-hydrogen bicarbonate buffer system • This is an important buffer system in the body. • The pairing of carbonic acid and hydrogen bicarbonate ion allows a reaction which occurs in both directions. • It allows hydrogen to be released or taken up depending upon the conditions in the blood.
  8. Oxidation-Reduction reaction • This reaction involves the transfer of electrons  Oxidation = loss of electrons  Reduction = gain of electrons • Electrons are very reactive • If oxidation occurs to one molecule, reduction must also immediately occurs to the other molecule • This reaction is called a REDOX Reaction
  9. Redox reactions in biology Cellular respiration is an example of redox reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O In this reaction Glucose molecule is oxidised to carbondioxide Oxygen is reduced to water.
  10. Condensation Reaction • This reaction is also called Dehydration synthesis. • This reaction is involved in the formation of all the four types of macromolecles. • In this reaction, H-atom is removed from a functional group of one molecule and an OH group is removed from another molecule This reaction releases water along with the formation of product
  11. Condensation reaction in Biology • Two amino acids form peptide bond by condensation reaction • In this reaction,  Peptide bond is formed which is represented in red colour  Water molecule is also released which is represented in blue colour
  12. Hydrolysis Reaction • This reaction helps in the breakdown of macromolecules into their monomers. Water is added to break the bonds between monomers. WATER gets IN, MONOMER gets OUT Hydrogen from the water is added to one monomer, and the OH group is added to the adjacent monomer. Covalent bond between the macromolecule breaks down to form two monomers.
  13. Hydrolysis reaction in biology • Phosphatases break the oxygen‐phosphorus bond of phosphate esters: • Other hydrolases function as digestive enzymes, for example, by breaking the peptide bonds in proteins.
  14. Group transfer reactions • In this reactions functional groups move from one molecule to another. • The enzymes involved are called transferases • For example, alanine aminotransferase shuffles the alpha‐amino group between alanine and aspartate: • Other transferases move phosphate groups between ATP and other compounds, sugar residues to form disaccharides, and so on.
  15. Reactions involved in formation or removal of a double bond with group transfer • The functional groups are transferred by the lyase enzymes which include amino groups, water, and ammonia. • For example - Deaminases remove ammonia in the process of removal of amino groups from amino acids.
  16. Isomerization Reaction • In this reaction, the position of a functional group is changed within a molecule. • Here, the molecule itself contains the same number and kind of atoms that it did in the beginning. • The enzyme, isomerases carry out these rearrangements. • Example – (Enzyme – triose phosphate isomerase)
  17. Reactions involved in single bond formation by eliminating the elements of water • In this reactions, water molecule is removed from two functional groups to form a single bond. • The enzyme, ligases carry out the reactions. • For example, aminoacyl‐transfer RNA synthetases join amino acids to their respective transfer RNAs in preparation for protein synthesis
  18. Conclusion • Trillions of chemical reactions happen simultaneously in the body. They lead the processes that keep a human body ‘alive’. • They are collectively known as metabolism. • Metabolism is made up of numerous metabolic pathways. • A metabolic pathway is a sequence of chemical reactions that follow a set of ‘instructions’ contained in the body’s DNA. • Enzymes are biochemical catalysts that alter the rate of reactions. However, unlike most chemical catalysts, enzymes are highly selective and only promote specific reactions.