Biological Molecules- protiens and enzymes
- Created by: gsemma
- Created on: 07-10-18 10:29
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- Proteins
- amino acids
- building block of all proteins
- joined by peptide bonds
- 2= dipeptide
- many= polypeptide
- covalent bond between carboxyl group and hydroxyl group of 2 AA and release oxygen
- broken apart by hydrolysis
- enzymes catalyse this
- formed by condensation reactions
- enzymes catalyse this
- formed by condensation reactions
- joined by peptide bonds
- general structure (draw)
- R= variant. 20 different ones
- simplest is H making Glycine
- building block of all proteins
- Enzymes
- structure
- globular proteins
- specific active site to the substrate
- tertiary structure determines this
- lock and key model
- active site is ridged where substrate fits exactly
- forms enzyme substrate complexes
- active site is ridged where substrate fits exactly
- products separate form enzyme and the enzyme is unchanged
- induced fit model
- active site is not ridged- can slightly change
- an enzyme substrate complex is formed when the enzyme forms around the substrate.
- when the products leave, the enzyme returns to original shape
- an enzyme substrate complex is formed when the enzyme forms around the substrate.
- active site is not ridged- can slightly change
- activation energy
- amount of energy needed for a reaction to occur
- enzymes provide an alternative pathway and reduce the activation energy
- this speeds up reactions and allows them to occur at lower temperatures.
- enzymes provide an alternative pathway and reduce the activation energy
- amount of energy needed for a reaction to occur
- Factors affecting enzyme function.
- temperature
- increase rate as there is more kinetic energy meaning the enzyme substrate complexes are formed faster and are more likely to happen
- if the temp gets to high the enzyme will denature
- increase rate as there is more kinetic energy meaning the enzyme substrate complexes are formed faster and are more likely to happen
- substrate concentration
- higher conc leads to increased rate due to a greater chance of ESC being formed.
- it will reach a saturation point where no more ESC will be formed as all enzymes are used up
- once all the substrate has been used up, the reaction will top.
- it will reach a saturation point where no more ESC will be formed as all enzymes are used up
- higher conc leads to increased rate due to a greater chance of ESC being formed.
- pH
- at optimum- fastest rate. below will be slower and above will cause enzymes to denature.
- Enzyme conc
- same as substrate conc and limiting factor is amount of substrate
- temperature
- enzyme inhibitors
- competitive
- their shape is complimentary t the active site of the enzyme where they bind so no reactions can take place
- If one forms a covalent bond with the enzyme the effect is irreversible
- if a hydrogen bond if formed the effect is reversible because it is weaker.
- non-competitive
- bind to enzyme's allosteric site and causes it to change shape so nor reactions can take place
- If one forms a covalent bond with the enzyme the effect is irreversible
- if a hydrogen bond if formed the effect is reversible because it is weaker.
- competitive
- structure
- Different levels of structure
- primary structure
- sequence of amino acids held by peptide bonds. each protein has own sequance
- secondary structure
- interaction between amino acids- beta plated or alpha helices
- determined by hydrogen bonding between carboxyl and amino groups
- interaction between amino acids- beta plated or alpha helices
- tertiary structure
- further coiling to give 3D shape of polypeptide
- held by H bonds, ionic bonds, disulphur bonds and hydrophobic and hydrophilic interactions.
- ionic- attraction between positive and negative R groups
- disulphide- 2 sulphurs called cysteine bonds together
- held by H bonds, ionic bonds, disulphur bonds and hydrophobic and hydrophilic interactions.
- further coiling to give 3D shape of polypeptide
- Quaternary structure
- how several polypeptide chains
- determined by tertiary structure so all bonds contribute
- how several polypeptide chains
- primary structure
- test
- biuret
- add sodium hydroxide to sample to make it alkaline
- add copper sulphate to sample
- blue to purple when positive
- add copper sulphate to sample
- add sodium hydroxide to sample to make it alkaline
- biuret
- amino acids
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