1 / 36

Chemical components of living organisms

Chemical components of living organisms. Learning objectives. To identify the basic chemical components of living organisms. To define roles of carbohydrates, proteins and lipids in terms of energy storage and structural components.

joan-jarvis
Download Presentation

Chemical components of living organisms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chemical components of living organisms

  2. Learning objectives • To identify the basic chemical components of living organisms. • To define roles of carbohydrates, proteins and lipids in terms of energy storage and structural components. • To describe formation of carbohydrate, proteins and lipid from basic units. • To identify deoxyribonucleic acid (DNA) and ribonucleic acid(RNA) with their bases. • To differentiate between DNA and RNA.

  3. The basic chemical components of living organisms • Carbohydrate • Proteins • Lipids • Nucleic acids • Water • Mineral salts

  4. Carbohydrate • Carbon + Hydrogen + Oxygen • General formula: Cx(H2O)y. • Types of carbohydrates: ~ Monosaccharides ~ Disaccharides ~ Polysaccharides

  5. Monosaccharide • Sweet & soluble. • General formula: Cn(H2O)n. • Glucose, fructose & galactose

  6. Glucose • Found in all living cells • Chief end-product of carbohydrate digestion in gut

  7. Fructose • Found in fruits and in honey.

  8. Galactose & ribose • Galactose ~ Found in milk • Ribose ~ Constituent of ribonucleic acid(RNA) and deoxyribonucleic acid (DNA)

  9. Disaccharide • 2 monosaccharides joining together by glycosidic bond undergoing a condensation reaction. • Disaccharide can be split into its constituent monosaccharides by hydrolysis. • Sweet, soluble and crystalline • Maltose, sucrose, lactose

  10. Maltose • Glucose + Glucose Maltose • Glucose + Glucose +……  starch • It is hydrolysed back to 2 glucose molecules by maltase.

  11. Sucrose • Glucose + fructose  sucrose • It is also called cane-sugar. • It is hydrolysed back to glucose and fructose by invertase.

  12. Lactose • Glucose + galactose lactose • It is hydrolysed back to glucose and galactose by lactase. • Lacking lactase in the body  lactose intolerance

  13. Polysaccharides • Complex sugar • Compounds of a large number of monosaccharides units • Insoluble • Converted into monosaccharides upon hydrolysis • As food and energy store

  14. Polysaccharide • Starch ~ major food reserve stored in plants but absent in animal. • Glycogen ~ animal starch, stored in liver & muscles. • Cellulose ~ constitute of plant cell wall, insoluble in water & dissolves in concentrated sulphuric acids.

  15. Function of carbohydrates • As respiratory substrate • As storage material • As structure material

  16. Tests for carbohydrates Reducing sugar: • Benedict’s test • Clinistix paper test Non-reducing sugar: • Acid hydrolysis • Enzyme action Starch • Iodine test

  17. Lipids • Carbon + Hydrogen + Oxygen • Insoluble in water but dissolve in organic solvents. • Fat: semi-solid at room temperature • Oils: liquid at room temperature • Types of lipids: triglycerides, phospholipids

  18. Food reserve Structural materials Insulation Water-proof layer Transport medium Metabolic regulators Energy source Protection Others Function of lipids

  19. Tests for lipids • Grease spot test • Sudan III test

  20. Proteins • Polymer of amino acids • Insoluble in water • Carbon + Hydrogen + Oxygen + nitrogen +/- sulphur & phosphorus • Basic units: amino acid

  21. Proteins • Amino acid + Amino acid  Dipeptide • Dipeptide + Dipeptide  Polypeptide • The reaction “” is condensation. • 4 types of bonding: disulphide bond, ionic bond, hydrogen bond & hydrophobic interaction.

  22. Structure of proteins • Primary structure • Secondary structure • Tertiary structure • Quaternary structure

  23. Denaturation • Denaturation ~ loss of specific three dimensional conformation of a protein molecule; ~ but the amino acids sequence remains unaffected; ~ loss of biological activities

  24. Factors causing denaturation • Heat or radiation • Extreme pH • Inorganic chemicals • Organic chemicals • Mechanical force • Strong hydrogen bond former

  25. Renaturation • the protein resume its natural configuration; • the protein regains its normal activity

  26. Fibrous protein ~ regular repetitive sequences of amino acid; ~ parallel chain; ~ insoluble in water ~ e.g. collagen of tendons & ligaments Globular protein ~ irregular sequences of amino acid; ~ spherical & globular shapes chains; ~ e.g. enzymes, antibodies & hormones. Types of proteins

  27. Structural materials Biocatalyst Metabolic regulators Transportation Protection Muscle contraction Storage Toxins Respiratory substrate Functions of proteins

  28. Tests for proteins • Biuret test • Albustix paper test

  29. Nuleotides • Phosphoric acid + Pentose sugar + Organic base • The three components are combined by condensation reaction

  30. Types of nucleotides • Mononucleotides: only one nucleotide unit, e.g. ATP • Dinucleotides: 2 nucleotides e.g. NAD • Polynucleotides: repeated condensation of nucleotides e.g. RNA & DNA

  31. RNA • Ribonucleic acid • Single –stranded polymer of nucleotide • Organic bases: A, G, C AND U

  32. DNA • Deoxyribonucleic acid • Double-strand polymer, form double helix • Organ bases: A, G, C and T

  33. DNA Single strand Base: A, T, C & G Sugar: Deoxyribose Size: long & large Stability: alkali-stable Function: carry genetic information Occurrence: innucleus RNA Single strand Base: A, U, C & G Sugar: ribose Size: short & small Stability: stable Function: protein synthesis, carry genetic information from DNA Occurrence: throughout cell DNA vs RNA

  34. Water • Comprise 65-95% of living cells. • High specific heat. • Strong hydrogen bond. • Universal solvent. • High tensile strength and high viscosity. • High surface tension

  35. Importance of water to life • Component of protoplasm. • Universal solvent. • Participating in metabolic process. • Cell turgidity. • Surface film. • Temperature stability. • Translocation medium.

  36. Mineral salt • Calcium • Chlorine • Phosphate • Fluorine • Iodine • Iron

More Related