🏥 Chapter 4 - Enzymes

• What are enzymes?


  Proteins that are a biological catalysts. They speed up reactions while remaining chemically unchanged after the reaction and can catalyse another reaction.

  
  

  
  

  They provide an alternative pathway with lower activation energy, which is the energy needed to start a chemical reaction.

  
• How do enzymes work?

  active sites-

  
  

  grooves on the surface of an enzyme that a substrate with a complementary shape can fit in, like a lock to a key, enzyme being the lock and substrate being the key. when substrate binds with active site, an Enzyme-Substrate complex is formed, and reactions take place, substrate --> products

  
• How enzymes and substrate react?

  (The enzyme)'s active site has a complementary three-dimensional shape to (the substrate), thus (the substrate) enters the active site, and binds to it, forming an enzyme substrate complex, where the chemical reaction starts to occur. The substrate is then converted to its products, and they leave the active site. The enzymes remains chemically unchanged after the reaction and can catalyse another reaction

  
• what are the characteristics of enzymes?

  1. they speed up chemical reactions by lowering activation energy needed to start a reaction

  
  

  2. They are specific in action, and only enzymes and substrates with complementary three-dimensional shapes can react

  
  

  3. they are required in minute amounts since they remain chemically unchanged after a reaction.

  
• How does temperature affect the rate of reaction?

  From A, rate of enzyme reaction is low, as kinetic energy and temperatures are low, thus rate of collision between enzyme & substrate are very low, and movement of enzymes are very slow, hence resulting in a slow formation of an E-S complex.

  
  

  From A-B, rate of enzyme reaction is increasing, as kinetic energy increases with temperature, thus rate of collision between enzyme & substrate increases, and movement of enzymes are increasing, hence resulting in a faster formation of an E-S complex.

  
  

  At Point B, the enzyme is at its optimum temperature and rate of reaction is the highest., and this is where the enzyme is the most active

  
  

  From B to C, the rate of reaction decreases as enzymes begin to denature and the active site is lost.

  
  

  At C, rate of reaction is 0 and enzymes have completely denatured

  
• how does pH levels affect rate of reaction

  At pH 7, the pH is optimum, and rate of reaction is the highest. Enzymes are most active at the optimum pH.

  
  

  As pH decreases from 7-4 and increases from 7-10, away from optimum pH, rate of reaction decreases, and enzymes begin to denature and active site is lost.

  
  

  At pH 4 the pH is the most acidic and at pH 10 the pH is the most alkaline, hence enzymes are completely denatured and rate of enzyme reaction is 0.

  
• yt video on chapter


  https://www.youtube.com/watch?v=gUncqL1ul8Q