Define:
Enzymes
biological catalysts that speed up the chemical reactions inside of a living organism
Define:
Optimum
the best condition for enzymes to work properly /effectively
Define :
Catalyses
speeds up a chemical reaction without being used up themselves
During the catalase demonstration a liver was placed in a beaker of water and a beaker of hydrogen peroxide.
Hydrogen peroxide is a harmful by-product of respiration ,liver contains catalase which breaks it down,
What does it break it down into?
Hydrogen peroxide ——–>
water + oxygen
Define:
specificity
when an enzyme only reacts with one substrate
(most enzymes)
How does this demonstration explain the specificity of enzymes ?
the enzyme catalase in the liver breaks down hydrogen peroxide into water and oxygen, but does not react with water
define :
denaturation
when an enzyme experiences high temperatures or pH extremes , which changes the shape of the active site (meaning that it can no longer bind to its substrate)
define : complementary
when the shape of the substrate fits perfectly to the active site of the enzyme so it can bind to it
note:
enzyme’s active site is complementary to one specific substrate
give 4 ways a rate of reaction can be increased
-increasing (substrate) concentration
-increasing temperature (up to an enzyme’s optimum)
-increasing surface area (for solids)
-add a catalyst (e.g. an enzyme)
What is the name given to the substrate after going through reaction?
products
enzymes are ………… ,they only catalyse one reaction by ….. with a matching substrate
As the …… increases ,so does the rate of reaction until it reaches ……… Above this temperature it then becomes too … and the enzyme becomes ………
MEMORISE:
enzymes are SPECIFIC, they only catalyse one reaction by BINDING with a matching substrate
(honestly ignore the rest of this slide as it will be on slide 13)
As the TEMPERATURE increases ,so does the rate of reaction until it reaches OPTIMUM . Above this temperature it then becomes too HOT and the enzyme becomes DENATUREED
what will happen if an enzyme is placed in lower temperatures , what will happen if it is increased?
(honestly ignore the rest of this slide as it will be on slide 13)
If an enzyme is placed in lower temperatures ,the rate of reaction is slower due to a decrease in kinetic energy and decreased collisions
as the kinetic energy increases particles move faster and the substrate and active site are more likely to collide (increasing the rate of reaction)
Explain how the temperature affect the rate of reaction of enzymes
At low temperatures , the rate of reaction is slow because particles have less kinetic energy so move slower , there are decreased collisions.
As the temperature increases, the rate of reaction increased up to the optimum temperature, this is because particles have more kinetic energy , move faster and therefore it is more likely for a collision between the substrate and active site to occur, this increases the rate of reaction.
Above the optimum temperature , the enzyme gains a lot of kinetic energy which causes the structure of the enzyme and actice site to change shape , the enzyme becomes denatured so the substrate can longer bind to the active site and the reaction stops.
Is denaturation reversible?
No - it is irreversible
- the enzyme can no longer bind with the substrate and there is no reaction
What will happen if the enzyme is placed in too hot temperature?
(honestly ignore the rest of this slide as it will be on slide 13)
at higher temperatures the enzyme gains a lot of kinetic energy which causes the structure of the enzyme and the active site to change shape and stop working
-denaturation
as the pH …… so does the rate of reaction until it reaches the ……. when the pH becomes too .. and the rate of reaction decreases . The enzyme becomes …
(honestly ignore the above and just remember answer to this question)
How does pH affect the rate of reaction of enzymes
memorise:
as the pH INCREASES so does the rate of reaction until it reaches the OPTIMUM when the pH becomes too HIGH and the rate of reaction decreases . The enzyme becomes DENATURED
Too extreme pH (too high or low / too alkaline or acidic) can denature enzymes
-enzymes work fastest at their optimum pH
True or False :
All enzymes work best at a similar pH
False -different enzymes work best in different conditions
What will happen if the pH changes?
pH changes can slow enzymes down or stop them working. They denature and can no longer bind to their substrate
NOTE: DO not say active site is denatured say the enzyme is denatured
example answer
(PROCESS right?)
enzymes are biological catalyst, they increase the rate of a chemical reaction without being used up themselves. They are made from proteins and have an active site where the reaction occurs.
(I feel this is just extra unless asked for)
The substrate enters the active site and binds to it - this is called an enzyme -substrate complex . The enzyme will catalyse a reaction and the substances formed are called products. The active site of the enzyme is complementary to the substrate
