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biological molecules (inorganic ions (potassium (activates enzymes needed…

- - - - = the sequence of amino acids in the polypeptide chain
      - different proteins have different amino acids in their primary structure
      - formation of peptide bonds
    - - hydrogen bonds form between nearby amino acids in chain
      - cause the chain to coil into an alpha helix or a beta pleated sheet
    - - the polypeptide chain is folded and coiled further
      - more bonds form
      - polypeptide chain forms a 3D structure
      - other bonds which form
        
        ionic interactions
        
        weak attractions between negatively charged R groups and positively charged R groups on different parts of the molecule
        
        disulfide bonds
        
        whenever two molecules of the amino acid CYSTEINE come close together, the sulfur atom in one of the cysteine bonds to the sulfur in the other cysteine
        
        strongest type of bond available to form
        
        hydrophobic and hydrophilic interactions
        
        when hydrophobic R GROUPS are close together in the protein they clump together
        
        This means hydrophilic R groups are more likely to be pushed to the outside
        
        effects how protein folds and coils into finals structure
        
        hydrogen bonds
        
        form between a slightly positively charged hydrogen atoms in some R groups and slightly negatively charged atoms in other R groups on the peptide chain
    - - proteins are made up of multiple polypeptide chains held together by bonds
      - the way the protein is assembled
  - - - carries oxygen around body in red blood cells
      - has the haem R group which contains iron
      - oxygen bonds to iron
      - made of 4 polypeptide chains
  - - - forms supportive tissue in animals so needs to be strong and flexible
      - made of 3 polypeptide chains that are coiled into a triple helix
      - the chains are interlinked by strong COVALENT BONDS
      - minerals can bind to triple helix to increase rigidity
      - every 3rd amino acid is glycine
      - left handed helix
- - - - specific heat capacity= energy needed to raise the temp of 1 gram of a substance by 1 degree
      - hydrogen bonds ABSORB LOTS OF ENERGY
      - this means that water doesn't experience rapid temp changes (makes it a good habitat)
    - - it takes a lot of energy to break hydrogen bonds between molecules
      - so a lot of energy is used up when it evaporates
      - creates a cooling effect as it takes away lots of energy when it evaporates
    - - cohesion= attraction between molecules of the same type e.g. two water molecules
      - being polar cause water molecules to stick together / be cohesive
      - this helps water flow and makes it good for transporting substances, water is pulled up the xylem
    - - slightly positive end of water molecule will be attracted to negative ion and the slightly negative end of water will be attracted to positive ions
      - this causes ions to dissolve as they are surrounded by water
      - e.g. ions dissolve in the water in blood and can be transported around body
    - - at low temps water freezes
      - water molecules are held further apart in ice than they are in liquid water because each water molecules forms 4 HYDROGEN BONDS to other water molecules making it a lattice
      - this causes water to float and be less dense
      - ice forms an insulating layer on top of water preventing water below freezing so organisms can still move
- - - - two types of glucose alpha and beta
      - glucose= hexose monosaccharide (it has 6 carbons)
      - function= main energy source in animals and plants
      - structure makes it SOLUBLE in water (not in non polar solvents) so its easy to transport
    - - =pentose monosaccharide
  - - - amylose
        
        a long UNBRANCHED chain of a-glucose (1 to 4)
        
        angles of the glyosidic bonds give it a COILED STRUCTURE
        
        makes it compact and energy dense
      - amylopectin
        
        a long BRANCHED chain of a-glucose (branches are 1 to 6, others are 1 to 4
        
        side branches allow enzymes to easily break down molecule and reach glyosidic bonds easily
        
        allows energy to be released quickly
- - - - reducing sugars= all monosaccharides and some disaccharides
      - 1) add benedicts reagent to sample
      - 2) heat test tube in water bath as 80 degrees for 5 minutes
      - if the test if positive a coloured precip will form (blue to brick red)
      - 4) the higher the concentration the further the colour change goes
    - - 1) add dilute HCl to sample
      - 2) place in water bath at 80 degrees for 5 minutes
      - 3) then add sodium hydrogencarbonate
      - Then carry out test as you would for reducing sugar
      - if test is positive a coloured precip will form blue to brick red
- - - - triglycerides are synthesized by the formation of an ester bond between each fatty acid and the glycerol molecule
      - each ester bond is formed by a CONDENSATION REACTION where one molecule of water is released
      - the process by which ester bonds are synthesized = ESTERIFICATION
      - ester bonds are broken down by HYDROLYSIS
    - - saturated
        
        fatty acids don't have double bonds between carbon atoms
      - unsaturated
        
        have at least one double bond between carbon atoms
        
        causes chain to kink
  - - - ENERGY STORAGE MOLECULES
      - long hydrocarbon tails of fatty acids contain lots of chemical energy- lots of energy is released when broken down (2x as much energy as carbohydrates)
      - INSOLUBLE- don't cause water to enter cells by osmosis which would make them swell. triglycerides bundle together as insoluble droplets (hydrophobic tails face inwards)
    - - FOUND IN CELL MEMBRANES
      - heads are hydrophilic, tails are hydrophobic- form a double layer with heads facing outwards
      - centre of bilayer is hydrophobic so water-soluble substances cants easily pass through- acts as a barrier
    - - small size and flattened shape- allows cholesterol to fit between phospholipid molecules in membrane
      - they bind to hydrophobic tails of phospholipids causing them to pack more closely together- makes membrane more rigid/ controls fluidity
      - its a steroid alcohol