BIO_Ch05_SQ_e.doc - HKDSE BIOLOGY: Connecting Concepts...

This preview shows page 1 - 4 out of 15 pages.

The preview shows page 2 - 4 out of 15 pages.
HKDSE BIOLOGY: Connecting ConceptsChapter 5Question bankShort questionsShort questions|!|BCESB0050000001|!|SIThe enzyme lipase catalyses the breakdown of lipids.(a)Write a simple word equation to represent the reaction catalysed by lipase. (1 mark)(b)An experiment was carried out to investigate the effect of temperature on theactivity of lipase. The reaction mixtures were maintained at three differenttemperatures for an hour. The initial pH and final pH of the mixtures weremeasured and recorded in the table below.Temperature at whichthe reaction mixturewas kept (oC)Initial pH of themixtureFinal pH of themixture57.06.8407.05.9707.07.0(i)Describe and explain the result of the mixture kept at 40oC.(3 marks)(ii)Explain the relative inactivity of lipase at each of the other twotemperatures.(2 marks)
© 2019Aristo Educational Press Ltd.1
HKDSE BIOLOGY: Connecting ConceptsChapter 5Question bankShort questions(ii)At 5oC, the kinetic energy of the substrate and enzyme molecules is low, sothe chance of forming an enzyme-substrate complex is low.(1)At 70oC, the enzymes are denatured by the high temperature and have losttheir catalytic function.(1)________(6 marks)##Skills assessedMarks(a)Understanding basic concepts1(b)(i)Applying concepts3(b)(ii)Applying concepts2|!|BCESA0050000002|!|STSEMrs Lam and her son Johnny are comparing the cost-effectiveness of two brands ofwashing powders. Johnny washed some egg-stained clothes with the two differentwashing powders at 30 °C and at 80 °C respectively. The results are shown in the tablebelow.Washing powderTemperature (oC)Brand A($40 / 300 g)Brand B($60 / 300 g)30Egg stain remainedEgg stain disappeared80Egg stain disappearedEgg stain remained(a)Deduce which of the two brands is a biological washing powder.(3 marks)(b)Taking into account the effectiveness and cost of the two brands of washingpowders, which brand would you recommend Mrs Lam to use? Give a reason tosupport your answer.(2 marks)##
© 2019Aristo Educational Press Ltd.2
HKDSE BIOLOGY: Connecting ConceptsChapter 5Question bankShort questionsCompared with brand A, brand B removes egg stain at a lower temperature.(1)However, brand B can no longer remove egg stain at high temperature. Thissuggests that brand B contains enzymes which denature at high temperature.(1)(b)Brand B is recommended.(1)Brand B removes egg stain at a lower temperature. This saves energy despite thehigher price. (Or other reasonable answer)(1)________(5 marks)##Skills assessedMarks

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 15 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Fall
Professor
N/A
Tags
Enzyme, Aristo Educational Press Ltd

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture