Lecture 3

• Macromolecules 


  Many are polymers of repeated smaller molecules.
• In Living Things


  Biochemical reactions are very fast

  Reactions happen under mild conditions of temperature and pressure

  Cells have a huge diversity of reaction

  Living things require a continuous input of energy
• Biochemistry 


  A cell make many macromolecules- huge molecules that need a lot of energy to produce.

  Many smaller molecules- for colour, scents, communication and parts of larger molecules.
• Why make macromolecules?


  Cells arise by dividing of pre-existing cells

  Need informational macromolecules for cells structure and function

  Food- need to be able to store excess energy for harder times.

  An organism- It needs functional molecules for protection, movement, controlling reactions and communication
• Macromolecules in four groups


  Proteins- Functional and structural molecules

  Polysaccharides- Energy store and structure

  Nucleic acid- Information store and transfer

  Lipids- Energy store and structure ( includes fats)

  Polymers- A long chain of covalently- joined building blocks called monomers.
• Polymer synthesis in the cell


  Dehydration removes water molecules to form a new bond.

  One monomer is added by each dehydration reaction

  New monomer is only added to the end of the polymer

  
• Polymer synthesis in cells (hydrolysis)


  Hydrolysis adds a water molecule, breaking a bond.

  For reuse within the cell or organism

  Digestion- if eaten by something else and decomposition

  
• Why is energy needed in polymer synthesis?


  Energy is required to make larger molecules from smaller ones. Usually energy is added to the monomer by an earlier reaction, production an Activated monomer.
• Distinguish between an amino acid, a polypeptide and proteins:


  Amino acids are molecules that form to make a protein.

  Polypeptides are linear polymers of covalently- bonded amino acids.

  Proteins- one or more polypeptides folded into a specific conformation to enable function.
• Macromolecules

  many are polymers that are made of repeated smaller polymer units
• polypeptides

  liner polymer of covalently bonded amino acids
• proteins 


  one or more polypeptides folded into a specific conformation to enable function