GCSE AQA BIOLOGY FOUNDATION QUESTIONS ON ENZYMES

GCSE AQA BIOLOGY FOUNDATION QUESTIONS ON ENZY
MES


The effect of pH on the rate of reaction of amylase –
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| Aiming for grade 4
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Specification |references:
 Required |practical |5: |investigate |the |effect |of |pH |on |the |rate |of |reaction |of
|amylase |enzyme.


 4.2.2.1 |The |human |digestive |system.
 MS |1a, |MS |1c
 WS |2.1, |WS |2.4, |WS |2.5, |WS |2.6, |WS |3.1, |WS |3.2
 AT |1 |Use |appropriate |apparatus |to |record |the |volumes |of |liquids, |time |and |pH.
 AT |2 |Safe |use |of |a |water |bath |or |electric |heater.
 AT |5 |Measure |the |rate |of |reaction |by |the |colour |change |of |iodine |indicator.
 AT |8 |Use |of |qualitative |iodine |reagent |to |identify |starch |by |continuous
|sampling.




Aims
In |this |practical |you |will |use |a |continuous |sampling |technique |to |determine |the
|time |taken |to |completely |digest |a |starch |solution. |You |will |repeat |the |experiment

|at |different |pH |levels |to |investigate |how |pH |affects |the |time |taken |for |this |enzyme

|controlled |reaction |to |occur.




Learning |outcomes
After |completing |this |required |practical, |you |should |be |able |to:
 list |some |factors |that |affect |the |rate |of |an |enzyme |controlled |reaction
 describe |how |iodine |indicator |is |used |to |determine |the |end |point |of |an |enzyme
|controlled |reaction


 record |the |time |it |takes |for |an |enzyme |controlled |reaction |to |occur
 determine |the |optimum |pH |for |amylase |to |break |down |starch |into |glucose
 with |some |support, |draw |a |graph |of |amylase |activity |against |pH.

Safety
 Use |eye |protection.
 Iodine |is |harmful; |avoid |contact |with |skin.