C4 Enzymes Flashcards
why are enzymes important?
4.1 Enzyme Action
- catalyse reactions
Role of enzymes
(growth)
4.1 Enzyme Action
- living organisims need to be built and maintained
- anabolic reactions
Lock and Key Hypotheses
4.1 Enzyme Action
- area within the tertiary structure of the enzyme has a shape complementary to the substrate.
- when the substrate is bound it becomes the enzyme-substrate complex
- when the products are formed it becomes the enzyme-product complex
- r-groups within the active site interact and form temporary bonds.
Induced-fit Hypotheses
4.1 Enzyme Action
- active site can slightly change
- initial interaction is weak but induce chnage of the tertairy structure of the enzyme
- strengthens bonds
- weakne bonds in substrate- lowering activatiion energy
Intracellular Enzymes
4.1 Enzyme Action
- enzymes which act within cells
- roles within structure and function of cells
- synthesis of polymers and monomers
Extracellular Enzymes
4.1 Enzyme Action
- ** enzymes released to break down large molecules into smaller ones in the proccess of digestion**
- proteins and other polmers cannot enter cells directly due to size
- broken down by extracellular enzymes
Digestion of Starch
4.1 Enzyme Action
digested in two steps
1. amalyse partially breaks down starch into maltose. produced in salivary glands and pancreas.
2. maltase breaks down maltose into glucose. present in the small intestine.
Digestion of Proteins
4.1 Enzyme Action
- trypsin is a protease which catalyses the digestion of proteins into smaller peptides, then amino acids.
- produced in the pancreas and released into the small intestine
Temperature
4.2 Factors Affecting Enzyme Action
- increasing temperature, increaeses kinetic energy
- the temperature coefficient is how ,much the rate of reaction increases with a 10^c rise
- increased temperarture causes the bonds to vibrate and eventually break. This results in the changing shape- denaturing
Optimum Temperature and Temperature Extremes
4.2 Factors Affecting Enzyme Action
- optimum is where the enzyme has the highest rate of activity.
———————————————————— - some enzymes are adpated to the extreme cold- they have really flexible active sites so denature with small temperature rises,
- thermophilles are adapted to the hot temperatures- more stable as they have more bonds in tertiary structure, more resistant to temp changes
PH
4.2 Factors Affecting Enzyme Action
- hydrogen and ionic bonds between amino acid R-groups hold the protein togther i. precise 3D shape.
- Change in PH is change in in hydrogen ion concentration- this changes the active site shape
- if PH shifts from the optimum the active site is altered. this can then retun back to the optimum and the reaction will continue
- If the PH changes to extremely the Enzyme will denature
- The rate will increase up to its maximum- all the active sites are occupied.
Inhibitors Defenition
4.3 Enzyme Inhibitors
- molecules that prevent enzymes from carrying out their normal functions
- they stop the build up of excess product
- there are two types: competiitve and non-competitive
Competetive Inhibition
4.3 Enzyme Inhibitors
- a molecule with a simalr shape to substae , fits to the active site.
- This blocks the substrate, preventing the enzyme catalysing the reaction.
- The substare nd inhibitor compete to bind to the active site
- There are less substrates binding therefore slowing down ROR.
Effect of Competitve Inhibition
4.3 Enzyme Inhibitors
- Most only bind temporelrily so are reversible
- competitve inhibitors dont change the Vmax of the enzyme.
- E.G statins
Non-Competive Inhibition
4.3 Enzyme Inhibitors
- Inhibitor binds to the enzyme but not in active site.
- Changes the tertairy structure- chnages active site shape
- Substrate can no longer bind to the enzyme
- Enzyme cannot carry out its function
- Doesnt compete with the inhibitor.
