Unit 3 Aos 2

• Enzyme inhibitors can either decrease or completely stop the activity of enzymes.
• Noncompetitive inhibition involves binding of an inhibitor at another site on the enzyme, causing a conformational change that reduces its ability to catalyze reactions.
• Competitive inhibition occurs when an inhibitor competes with substrate molecules to bind to active sites on enzymes, reducing their effectiveness.
• The active site of an enzyme is the part of an enzyme where the substrate binds
• Enzymes are molecules that are organic (carbon-based) catalysts, which means that they speed up, or catalyse, chemical reactions that would normally take much longer to occur.
• catalyst a substance capable of increasing the rate of a reaction without being used up
• catalyse to increase the rate of a reaction
• Enzymes bind to a molecule called a substrate, which is the name given to the reactant undergoing an enzyme facilitated reaction, which forms a product
• A substrate binds to an enzyme’s active site, which then the active site undergoes a conformational change to accommodate the substrate, and the substrate undergoes a small change in turn. The reaction then occurs and the products leave the enzyme so that it can continue to catalyse future reactions.


  What do enzyme-catalysed reactions look like?
• The enzyme is considered neither a reactant nor a product, it is written above the arrow in an equation.
• The activation energy is defined as the minimum amount of energy required to energise atoms or molecules to a state where they can undergo a chemical transformation.


  What is activation energy?
• Every chemical reaction requires an input of energy to start.
• According to collision theory, in order for molecules to react with one another they need to ‘collide’ with enough kinetic energy o overcome the activation energy of the reaction
• An anabolic reaction is when two or more smaller molecules combine to form a larger one (i.e. building things up), whereas a catabolic reaction is a larger molecule turning into two or more smaller molecules (i.e. breaking things down).
• Enzymes function to lower the activation energy of chemical reactions by bringing reactants closer to the state they need to be in order to react
• 
  

  Biochemical pathway are a series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. Also known as a metabolic pathway
• Enzymes are capable of catalysing reactions continuously, and frequently ‘team up’ to work in chains of reactions.
• Enzymes are specific, are not used up in reactions, can sometimes work in both directions of a reaction (anabolic and catabolic), and can catalyst each step of entire metabolic pathways
• Chloroplast


  A membrane-bound organelle only found in plants and photoautotroph cells that is the site of photosynthesis
• Photosynthesis occurs in the leaves of plants
• Glucose is used immediately as a source of energy for cellular respiration
• Stomata


  Small pores on the leaf's surface that open and close to regulate gas exchange
• Stomata open

  Carbon dioxide diffuses into the leaf and oxygen out
• Chlorophyll


  A chemical found in the thylakoids of chloroplasts and is responsible for absorbing light energy in photosynthesis
• Bundle sheath cells


  Only for C4 plants
• Mesophyll cells


  A plant cell type found in leaves that contain large amounts of chloroplasts
• Enzymes bind to substrate


  Name of reactant undergoing an enzyme-facilitated reaction
• Enzymes speed up biochemical reactions by lowering the activation energy required to initiate a given reaction
• Enzymes have a 3D shape, either Tertiary or Quaternary, depending on the enzyme ; they can denture if the enzyme cannot form these shapes
• After binding, the substrate undergoes a transformation and forms a product that leaves the enzyme
• Enzymes are organic molecules, typically proteins, that catalyse specific reactions
• Enzymes speed up biochemical reactions by lowering activation energy required to initiate a given reaction
• Catalysts are substances capable of increasing the rate of reaction without being used up
• An enzyme cannot function if denatured
• Enzymes are reusable and can catalyse future reactions
• Enzymes bind to substrate for enzyme-facilitated reactions
• Most enzyme-catalysed reactions are reversible, with the enzyme often able to catalyse anabolic and catabolic processes
• Most enzymes only bind to one specific substrate, which means they tend to catalyse just one chemical reaction
• Enzymes speed up reactions but do not create new reactions
• Each enzyme has an active site where the substrate binds, allowing the reaction to occur