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Chemistry

Chemistry. Session. BIOMOLECULES - 2. Session Objectives. Enzymes Cofactors Sucrase Mechanism Carboxypeptidase Metabolism DNA and RNA Lipids Hormones and Vitamins. Enzymes. An enzyme is a protein that acts as a catalyst for a biological reaction.

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Chemistry

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  1. Chemistry

  2. Session BIOMOLECULES - 2

  3. Session Objectives • Enzymes • Cofactors • Sucrase Mechanism • Carboxypeptidase • Metabolism • DNA and RNA • Lipids • Hormones and Vitamins

  4. Enzymes An enzyme is a protein that acts as a catalyst for a biological reaction. Most enzymes are specific for substrates while enzymes involved in digestion such as papain attack many substrates

  5. Cofactors In addition to the protein part, many enzymes also have a nonprotein part called a cofactor The protein part in such an enzyme is called an apoenzyme, and the combination of apoenzyme plus cofactor is called a holoenzyme. Only holoenzymes have biological activity; neither cofactor nor apoenzyme can catalyze reactions by themselves A cofactor can be either an inorganic ion or an organic molecule, called a coenzyme Many coenzymes are derived from vitamins, organic molecules that are dietary requirements for metabolism and/or growth

  6. Types of Enzymes by Function Enzymes are usually grouped according to the kind of reaction they catalyze, not by their structures

  7. How Do Enzymes Work? Citrate Synthase Citrate synthase catalyzes a mixed Claisen condensation of acetyl CoA and oxaloacetate to give citrate Normally Claisen condensation require a strong base in an alcohol solvent but citrate synthetase operates in neutral solution

  8. → Sucrase Mechanism

  9. → → Sucrase Mechanism

  10. Active Site of Carboxypeptidase

  11. Carboxypeptidase's

  12. The Structure of Citrate Synthase Determined by X-ray crystallography Enzyme is very large compared to substrates, creating a complete environment for the reaction

  13. Aspects of Metabolism • Metabolism. • The life process. • Catabolism. • Substances are broken down. • Anabolism. • Substances are built up.

  14. Metabolism • Lipid metabolism. • Uptake of fats through walls of intestine. • Glycerol converted to glyceraldehyde-3-phosphate. • Fatty acids are oxidized by –oxidation. • Protein metabolism. • Stomach: • HCl and pepsin hydrolize 10% of peptide bonds. • Intestine: • Trypsin and chymotrypsin cleave peptide fragments further.

  15. Components of DNA and RNA DNA: Deoxyribonucleic acid. Chromosomes: Double stranded DNA rod-like structures. Genes: Specific locations on chromasomes that code for specific traits. RNA: Ribonucleic acid Contains ribose instead of deoxyribose. Generally single stranded.

  16. DNA Double Helix

  17. RNA Single Strand

  18. Focus On Protein Synthesis and the Genetic Code The genetic code How triplets of the four nucleotides unambiguously specify 20 amino acids, making it possible to translate information from a nucleotide chain to a sequence of amino acids.

  19. Transcription How RNA polymerase, guided by base pairing, synthesizes a single-stranded mRNA copy of a gene’s DNA template

  20. Protein Synthesis(Translation) Translation How base pairing between mRNA and tRNAs directs the assembly of a polypeptide on the ribosome

  21. DNA Replication

  22. Click here

  23. Lipids

  24. Some Common Fatty Acids

  25. Saponification

  26. Fats and Oils • Both are triglycerides. • Differ in the nature of the acid components attached. • Both are colorless, odorless and tasteless • Flavors and aromas come from organic impurites. • Fats. • Predominantly saturated fatty acids. • Normally solid at room temperature • Oils. • Predominantly unsaturated fatty acids. • Liquids at room temperature.

  27. Butter

  28. “Calorie-Free” Fats

  29. Phospholipids

  30. Phospholipids

  31. Hormones Hormones are molecules that transfer information from one group of cells to a distant tissue or organ. They are produced by various endocrine glands. They are classified on the basis of their structure or site of activity in the cell.

  32. Vitamins • They are essential dietary factors required by an organism in minute quantities. • They are essential for life and their absence causes deficiency diseases. • Vitamins catalyze biological reactions in very low concentration • Vitamins are designated A,B,C,D,etc. in order of their discovery. Subgroup vitamins are designated by number subscript e.g. B1,B2,B6,B12 • Classification: • Fat soluble • Water soluble

  33. Thank you

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