BIO_Ch05_LQ_e.doc - HKDSE BIOLOGY: Connecting Concepts...

HKDSE BIOLOGY: Connecting Concepts Chapter 5
Question bank Structured questions
Structured questions
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 SI
An experiment was carried out to investigate an enzyme-catalysed reaction. The
concentration of a substrate or product was monitored in three tubes of reaction
mixtures as shown in the graph below.
(a) Identify whether each of the three curves represents the changes in the
concentration of a substrate or product. (3 marks)
Curve X:
Curve Y:
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curve X
curve Y
curve Z
Time (minute)
Concentration of substrate / product (%)
1

HKDSE BIOLOGY: Connecting Concepts Chapter 5
Question bank Structured questions
Curve Z:
(b) The reaction mixture in one of the three tubes was wrongly prepared, leading to a
different reaction rate.
(i) Suggest with a reason which curve corresponds to the wrongly prepared tube.
(2 marks)
(ii) Suggest two possible errors during the preparation of the reaction mixture.
(2 marks)
(c) Curve X eventually leveled off and did not reach 100%. Suggest an explanation for
this phenomenon. (2 marks)
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________
(9 marks)
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2

HKDSE BIOLOGY: Connecting Concepts Chapter 5
Question bank Structured questions
Skills assessed Marks
(a) Analysing data 3
(b)(i) Analysing data 1
Applying concepts 1
(b)(ii) Applying concepts 2
(c) Applying concepts 2
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 STSE
The graph below shows the activity of two types of amylases. Amylase A is found in
bacteria living in hot spring, while amylase B is found in barely grains.
(a) Describe the effect of increasing the temperature on the activity of amylase A.
Amylase activity
(arbitrary units)
Amylase A
Amylase B
(4 marks)
(b) Amylase A is used in the industrial production of beer. It is mixed with germinated
barley grains during the process.
(i) What is the action of amylase on the starch in barley grains? (1 mark)
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Temperature (°C)
Amylase activity
(arbitrary units)
Amylase A
Amylase B
3

HKDSE BIOLOGY: Connecting Concepts Chapter 5
Question bank Structured questions