enzymes

• an enzyme has one or more active sites, which can be occupied by only one substrate at a time
• the active site is the part of an enzyme where substrate molecules bind to form an enzyme-substrate complex
• enzymes are biological catalysts that speed up chemical reactions
• reactions can be increased by the change in temperature but the temperature cant be too high as it can damage the cell. the temperature can denature proteins and melt lipids which makes the cell unfunctional
• a catalyst is used to speed up a reaction without being used up in the reaction and remains unchanged and reusable. enzymes are a biological catalyst
• enzyme turnover number is the number of enzymes in a cell at a given time
• complementary binding is when 2 molecules bind to each other and form a complex
• factors that effect the shape of the active site?

  temperature, ph, inhibitors and cofactors
• activation energy is the energy required to start a reaction, it is the minimum energy required to start a reaction
• a reaction with low activation energy is going to be faster compared to a reaction with a high activation energy.
• enzyme catalyse the reaction by lowering the activation energy of the reaction which allows fast reactions to occur in low temperatures
• the active site applies physical pressure to the substrate to cause a reaction to occur
• enzymes can be activated by cofactors and inhibitors stops the reaction
• when a small concentration of inhibitors is added to the reaction, the rate of reaction decreases and when a large concentration of inhibitors is added to the reaction, the rate of reaction completely stops
• what are the 2 types of inhibitors?

  competitive and non-competitive
• competitive inhibitors are competing with the substrate for the active site. they have a similar shape to the substrate and as soon as they attach themselves to the enzyme they block the substrate from the active site and prevents the formation of enzyme-substrate-complex
• non-competitive inhibitors bind to a separate part of the enzyme (back)
• the allosteric site is the site of the enzyme that is not the active site and where the non-competitive inhibitors bind
• the non-competitive inhibitor bind can affect the shape of the enzyme as the chemical reaction is altered. as the shape has been altered the substrate cant fit into the active site so the reaction is stopped
• end-product enzymes are enzymes that catalyze the final step of a metabolic pathway
• when a product is made, they want a certain amount of a substance to be in the product. one of the products acts as an inhibitor to another enzyme in the pathway
• non-competitive inhibitors are used in end-produce inhibitors
• inhibition by feedback is when the end product stops the production of more of itself
• when there's too much concentration of a product, there will be more inhibitors and them inhibitors will bind to the allosteric site of the first enzyme in the sequence
• because there are loads of inhibitors going to the first enzyme the rate of inhibitor production decreases and the concentration of the substrate increases