Biological Molecules

• What elements make up carbohydrates?

  C

  H

  O

  
• What elements make up lipids?

  C

  H

  O

  
• What elements make up proteins?


  C

  H

  O

  N

  (and sometimes S)
• What elements make up nucleic acids?


  C

  H

  O

  N

  P
• Calcium ions


  Necessary for muscle contraction and nerve impulsion transmission
• Sodium ions


  Necessary for nerve impulse transmission and kidney function
• Potassium ions


  Necessary for nerve impulse transmission
• Hydrogen ions


  Necessary for catalysis of reactions
• Ammonium ions


  Necessary for the production of nitrate ions by bacteria
• Nitrate ions


  Necessary as a nitrogen supply to plants for amino acid and protein formation
• Chloride ions


  Necessary for the balance of positive charge of sodium and potassium ions in cells
• Phosphate ions


  Necessary for nucleic acid and ATP formation
• Hydroxide ions


  Necessary for catalysis of reactions and pH determination
• Water


  Water is a polar molecule, due to the uneven distribution of charge.

  Hydrogen bonds form between an oxygen (region of negativity) and a hydrogen atom (region of positivity) interact Individual hydrogen bonds are weak, but collectively are strong.

  
• What are the 4 key properties of water?

  - Solvent

  - Transport Medium

  - Coolant

  - Habitat
• Water (as a solvent)


  Many polar molecules dissolve readily in water because it is polar. The negative oxygen atom attracts positive solutes and the positive hydrogen atom attracts negative solutes

  Non-polar (hydrophobic) molecules do not dissolve in water

  
• What is the link to eukaryotic and prokaryotic cells with water as a solvent?

  The cytosol of eukaryotic and prokaryotic cells is mostly water. This means that solutes can dissolve easily and be transported
• Water (as a transport medium)

  Polar substances dissolve and are easily transported in water in animals (the blood) and plants (xylem/phloem)

  
• What is cohesion?


  Cohesion is the sticking together of water molecules due to hydrogen bonds

  
• Water (as a coolant)


  Water has a high specific heat capacity --> The advantage of this is that internal temperatures of animals and plants remain constant (make sure enzymes do not denature or reduce in activity).

  Water acts as a buffer against temperature changes

  Water also has a high latent heat of vaporisation

  This provides a cooling effect

  
• Water (as a habitat)

  Water buffers temperature and this provides a stable environment (in terms of temperature) for aquatic organisms

  Water also provides surface tension, which allows small invertebrate to move and live on the surface providing a habitat away from predators

  Ice is less dense than water due to hydrogen bonds. Therefore, ice floats on top of water providing a habitat for animals

  
• What is monomer?


  Smaller units that bind to form larger molecules
• What is a polymer?

  Made of lots of monomers bonded together
• Glucose is a monomer, it forms what polymer?


  Starch

  Cellulose

  Glycogen
• Amino acids are monomers, it forms what polymer?

  Proteins
• Nucleotides are monomers, it forms what polymer?


  DNA

  RNA
• Give examples of monosaccharides (monomers)


  Glucose

  Fructose

  Galactose
• Give examples of disaccharides (dimers)


  Maltose

  Lactose

  Sucrose
• Give examples of polysaccharides (polymers)


  Starch

  Cellulose

  Glycogen
• Structure of alpha glucose

  
• Structure of beta glucose

  
• What are disaccharides made up of?


  Made of two monosaccharides.

  A glycosidic bond forms via a condensation reaction (water is removed)

  
• Glucose + Glucose -->


  Maltose + Water
• Glucose + Galactose


  Lactose + Water
• Glucose + Fructose -->


  Sucrose + Water
• What is a hydrolysis reaction?


  Splitting apart molecules through the addition of water
• Glucose is a...


  Hexose sugar (6 carbon atoms)
• Give an example of a pentose monosaccharide

  Ribose
• What are the 2 polysaccharides of starch?

  Amylose and amylopectin
• Amylose


  Amylose is formed from alpha glucose molecules joined together by 1-4 glycosidic bonds.

  Amylose has an unbranched helical structure.