enzymes

• how do enzymes affect the rate of reaction?


  enzymes increase the rate of reaction - they act as biological catalyst
• what is an active site of an enzyme?

  the active site is the part of the enzyme that the substrate fits into
• give two variables that affect the rate of an enzyme controlled reaction?


  temperature and PH - all enzymes have an optimum temperature and ph they work best at
• what is the lock and key model of an enzyme?

  the lock and key model is a simplified model of enzyme action. it states that a reaction will only be catalysed if the shape of the substrate exactly matches the shape of the enzymes active site, so that the substrate fits directly into the active site.
• a student is investigating the effect on ph on the rate of amylase activity. suggest how the student could control the temp of the amylase and starch soloution during the experiment

  the student could use an electric water bath
• rate of reaction=?


  rate of reaction = amount of product formed / time
• what happens if a reaction gets too hot?

  the bonds holding the enzyme together will break. this changes the shape of the enzymes active site, so the substrate won't fit anymore. the enzyme is said to be denatured.
• why do we have enzymes in our body?

  to speed up the useful chemical reactions in the body
• what's a catalyst?


  a substance which increases the speed of a reaction without being changed or used up in the reaction.
• explain why an enzyme only catalyses one reaction

  the enzyme has a specific shape which will only fit one substrate