Back to 课程

Biology AS AQA

0% Complete
0/0 Steps
  1. 1-1-biological-molecules-carbohydrates
    11 主题
  2. 1-2-biological-molecules-lipids
    3 主题
  3. 1-3-biological-molecules-proteins
    5 主题
  4. 1-4-proteins-enzymes
    12 主题
  5. 1-5-nucleic-acids-structure-and-dna-replication
    8 主题
  6. 1-6-atp-water-and-inorganic-ions
    4 主题
  7. 2-1-cell-structure
    7 主题
  8. 2-2-the-microscope-in-cell-studies
    4 主题
  9. 2-3-cell-division-in-eukaryotic-and-prokaryotic-cells
    8 主题
  10. 2-4-cell-membranes-and-transport
    9 主题
  11. 2-5-cell-recognition-and-the-immune-system
    7 主题
  12. 2-6-vaccines-disease-and-monoclonal-antibodies
    6 主题
  13. 3-1-adaptations-for-gas-exchange
    6 主题
  14. 3-2-human-gas-exchange
    14 主题
  15. 3-3-digestion-and-absorption
    5 主题
  16. 3-4-mass-transport-in-animals
    6 主题
  17. 3-5-the-circulatory-system-in-animals
    4 主题
  18. 3-6-mass-transport-in-plants
    6 主题
  19. 4-1-dna-genes-and-chromosomes
    10 主题
  20. 4-2-dna-and-protein-synthesis
    3 主题
  21. 4-3-genetic-diversity-mutations-and-meiosis
    7 主题
  22. 4-4-genetic-diversity-and-adaptation
    6 主题
  23. 4-5-species-and-taxonomy
    4 主题
  24. 4-6-biodiversity
    9 主题
课 Progress
0% Complete

Exam code:7401

Biological molecules: reactions

  • Many biological reactions involve the formation of covalent bonds, which add strength and structure to a molecule

  • Two important reactions occur to form covalent bonds in molecules:

    • Condensation reactions

    • Hydrolysis reactions

Condensation reactions

  • A condensation reaction (also known as dehydration synthesis) occurs when monomers combine by covalent bonds to form polymers (during polymerisation) or macromolecules, and water is removed

Diagram showing polymerisation; monomers become a polymer, removing H2O. Top: written form, bottom: symbolic form with triangle symbols.
Written and symbolic illustrations of the removal of water to form a covalent bond between two or more monomers during a condensation reaction
Table showing organic molecules: carbohydrates, proteins, lipids, nucleic acids with covalent bonds: glycosidic, peptide, ester, phosphodiester, and bond diagrams.
Covalent bonds in organic molecules formed during condensation reactions

Hydrolysis reactions

  • Hydrolysis means ‘lyse’ (to break) and ‘hydro’ (with water)

  • In the hydrolysis of polymers, covalent bonds are broken when water is added

    Diagram showing polymer hydrolysis. Written: Polymer plus H2O forms monomers. Symbolic: Triangles with OH and H groups, showing breakdown into smaller units.
    Written and symbolic illustrations of the addition of water to break down covalent bond/s during a hydrolysis reaction

Examiner Tips and Tricks

You must be able to recognise and identify the location of the covalent bonds in the molecules and draw them. Note that these molecules may be unfamiliar to you.

Responses

您的邮箱地址不会被公开。 必填项已用 * 标注