Enzymes

• What are enzymes?


  Enzymes are organic carbon based proteins (Tertiary structure) that catalyse, speed up , reactions.
• What do Enzymes bind to?

  Enzymes binds to their specific substrates
• What happens when enzymes bind to the substrate?


  Upon binding , the substrates undergoes a chemical reaction and forms a product, leaving the enzyme. The enzyme is left unchanged free to catalyse further reactions.
• What is a catalyst?


  A substance capable of increasing the rate of a reaction without being used up
• What are the features of enzymes (10 points)

  1-Reusable

  2-Specific to their substrate

  3-Reversible (catalysed reactions are reversible)

  4-Speed up reactions

  5- Has an active site

  6- Are proteins

  7- Are a subset of catalysts (enzymes are organic catalysts however there are also inorganic catalysts)

  8- Act on entire biochemical pathways (enzymes catalyse each step)

  9- End in "ase'

  10- Above the arrow
• What is an active site?

  An active site is a part of the enzyme where the substrate binds.(a pocket like area)
• What is the relationship of the shape of active site and substrate?


  The enzyme's active site and substrate are complementary in shape
• What forms when a substrate binds to the enzyme


  When the substrate binds to the enzyme's active site, it forms an enzyme substrate complex. When they bind the active site undergoes conformational change to accomodate the substrate, and the substrate changes
• Substrate binding to the enzyme steps


  1- Substrate enters the active site of the enzyme

  2-Enzyme changes shape slightly and the substrate binds creating a enzyme -substrate complex

  3- Reaction occurs

  4-Products leave the active site of enzyme
• What is the lock and key model?

  Enzyme's active site acts as the lock and the substrate acts as the key. The substrate fits into the enzymes active sight in a specific way , due to their complementary shape. The specificity ensures that certain substrates bind to their specific active sites.

  
• What is the induced fit model?


  Induced fit model suggests that the enzymes active site changesh shape slightly to better fit the substrate, enhancing specificity and efficiency.
• Are enzymes reactants?


  Enzymes are considered neither a reactant nor a product
• What is activation energy?


  Activation energy is the energy required to initiate a reaction.
• How do enzymes catalyse reactions?


  By lowering activation energy required for the reaction to take place.
• In order for molecules to react with one another, what needs to happen?

  Molecules need to collide with one another with enough kinetic energy to overcome activation energy
• How do enzymes speed up biochemical reactions?

  By lowering the activation energy
• Do reactions occur without enzymes?

  Yes, the reaction happens regardless of containing an enzyme, however, when an enzyme is added into the reaction, it will speed up (catalyse)
• What model is more accurate in the representation of substrates binding to enzymes?


  Induced fit model
• What is metabolism?


  Metabolism refers to the collection of biochemical reactions that occur in living things.
• What is an anabolic reaction?

  An anabolic reaction is the build up of molecules. When small molecules build up to form a bigger molecule . Endergonic reaction.
• What is a catabolic reaction

  A catabolic reaction releases energy as molecules are broken down. Bigger molecules are broken down into smaller molecules. Exergonic reaction.
• How do enzymes begin a reaction?

  By lowering the activation energy
• What do enzymes do in biochemical pathways?


  One enzyme will function to catalyse a substrate into a product, which would become the substrate of the second enzyme
• Can enzymes work in two directions?

  Yes, they sometimes can work in both directions of the reaction
• What is a biochemical pathway?

  A metabolic pathway that is a series of enzymes-catalysed biochemical reactions in which the product becomes the next substrate of the next reaction. (product-> new substrate)
• What happens when an enzyme gets too hot?

  Enzymes denature and stop functioning when they exceed their optimal temperature.
• What happens when temperatures increase?


  When the temperature increases , molecules have greater kinetic energy, and collide with one another more frequently.
• What happens when temperature increases in enzyme catalysed reactions?

  When the temperatures increases, enzymes and substrates move faster collide with each other more frequently, allowing reactions to occur faster
• Does enzyme's activity increase indefinitely with temperature?

  Yes
• Does each enzyme have a specific optimal temperature?

  Yes, which its activity is greatest, meaning the enzyme and substrate collide and bind more frequently.
• What is denaturing ? (talk about structures)

  When the temperature is too hot , bonds between the tertiary and quaternary structures are broken down
• What does denaturing do to the active site of an enzyme?

  Denaturing causes conformational change to in the active site, causing the substrate to no longer fit into the active site
• Is denaturation reversible?


  No, enzymes cannot regain its function even if the temperature decreases
• What happens when an enzyme decreases temperature?


  When enzymes decrease lower than their optimal temperature, enzymes experience little to no activity and can freeze.
• When temperatures decrease , is it irreversible?


  No, unlike denaturing, when enzymes decrease in temperature, enzymes can regain their functionality when reheated.
• Does significant denaturing occur at lower temperatures?

  No, enzymes become inactive
• Do reactions occur when enzymes are not at their optimal temperature?


  Unless denatured or frozen, the reaction would still occur when the enzyme is not at its optimal temperature, just at a much slower rate.
• Does rate of reaction increases as temperature increases? Why, why not?


  Yes, as heated increases kinetic energy of the particles , moving faster in the heat than in the cold.
• What type of graph is a temperature graph? What is on each axis?

  A linear to the optimal point and a curve going down.

  Enzyme activity on y-axis

  Temperature on the x- axis
• What is tolerance range?

  Tolerance range is the wider range of a given condition that an enzyme can function under.