Biological Molecules

Anmerkungen:

• Biological Molecules

1. Water
   1. High specific heat capacity
      1. It needs a high amount of heat energy to heat the water by a small amount
      2. Aquatic habitats are thermally stable, so aquatic organisms do not have to endure extremes of temperature
   2. High latent heat of vaporisation
      1. A great deal of heat energy is needed to convert it from a liquid to a vapour
      2. It allows the body to cool by taking heat energy to turn the water to vapour
   3. High surface tension
      1. The water molecules attract one another due to the water being polar. O bonds to H and they "stick" together, and it takes a lot of energy to break these bonds
      2. Some organisms can walk on water. Water can form droplets and run off a ducks back
   4. Colourless with a high transmission
      1. It allows light to pass through so aquatic plants can photosynthesise
   5. Polar
      1. Makes it a good solvent
      2. Dissolves polar Molecules and ions
      3. Reactive- metabolite (made) in condensation reactions
      4. Lipids do not dissolve in water because they are non polar so do not bond or share electrons
   6. Hydrogen bonds form between O and H molecules, due to a small dipole + cheatgrass on H and a small dipole - charge on O
   7. Ice is less dense than water
      1. Ice floats- important for animals who live on ice as their habitats would not exist of ice sank
      2. Water freezes from the top downwards, so ice on top provides a layer between cold air and water, so fish deep in the water stay warmer for longer
      3. Waters maximum density of 1g/cm3 is at 4 degrees C
2. Carbohydrates
   1. Monosaccharides
      1. Isomers- same molecular formula but a different structural formula
         1. (CH2O)n where n= no. of carbons
      2. Glyceraldehyde
         1. Triose C3H6O3
         2. Intermediate (helps) in respiration Involved in energy release
      3. Ribose
         1. Part of the RNA or ATP nucleotide
         2. C5H10O5
      4. Deoxyribose
         1. Part of the DNA nucleotide
         2. Deoxy- one less oxygen
            1. C5H10O4
      5. Glucose
         1. Start molecule for respiration Transport sugar in animals
         2. C6H12O6
      6. Galactose
         1. Component in lactose (milk sugar)
         2. C6H12O6
      7. Fructose
         1. Sugar in fruit and intermediate in (helps in) respiration
         2. C6H12O6
   2. Disaccharides
      1. Maltose
         1. C12H22O11
         2. Glycosidic Bond 1-4
         3. Breakdown product of starch digestion
         4. alpha glucose + alpha glucose
      2. Sucrose
         1. Non-reducing
         2. alpha glucose + beta fructose
         3. C12H22O11
         4. Glycosidic bond 1-2
         5. Transport in plants
      3. Lactose
         1. C12H22O11
         2. beta glucose + beta galactose
         3. Glycosidic bond 1-4
         4. Milk sugar
   3. Polysaccharides
      1. Starch
         1. Compact to store large amounts of glucose in a small space
         2. Large- insoluble in water- does not affect water potential of cells used for storage
         3. Plant storage
         4. Lots of alpha glucose
         5. Branched- more ends- faster energy release
         6. Amylose- helix shape, 1-4 glycosidic bonds
         7. Amylopectin- branced, 1-4 glcosidic bonds with 1-6 glycosidic bonds branching off
      2. Glycogen
         1. Lots of alpha glucose units
         2. Storage carb in animals
         3. Similar structure to amylopectin but more branched because of more 1-6 bonds
         4. easily hydrolysed- split into alpha glucose monomers which are soluble so can be easily transported to where energy is needed.
         5. Large and insoluble- does not affect water potential of storage cells
      3. Cellulose
         1. main component of plant cell walls
         2. made from beat glucose- straight chain
         3. alternate monomers flipped 180 degrees- OH- groups stick out on both sides so form hydrogen bonds with other chains
         4. hydrogen bonds make it strong- prevents osmotic lysis in plant cells.
      4. Chitin
         1. made from beta glucose with 1-4 bonds
         2. similar structure to cellulose but has a nitrogen amino acid instead of OH in glucose units
         3. found in insects
         4. strong, waterproof, lightweight
         5. exoskeleton of arthropods
3. Protein
4. Lipids
   1. .........
5. Water
6. Carbohydrates
7. Protein