Multiple Choice Questions (MCQ) topic quiz Enzymes Instructions and answers for teachers These instructions cover the learner activity section which can be found on page 11. 11. This Lesson Element supports OCR A and A Level !iology A "#$%$&#'%$( and !iology ! "Advancing !iology( "#$%%&#'%%(. When distributing the activity section to the learners either as a printed copy or as a Word file you will need to remove the teacher instructions section
!he "ctivity This Lesson Element is a teaching and learning resource containing %$ multiple choice )uestions "*C+s( on the theme of en,ymes. ome )uestions might re)uire synoptic thin-ing using -nowledge and ideas from various topics across the full A Level content. This resource can be used to test and consolidate understanding understanding at the end of a topic or to revisit and refresh -nowledge at a later point in the course.
#ntroduction *ultiple choice )uestions allow rapid coverage of a wide range of sub/topics. Contrary to a widespread belief among students multiple choice )uestions are not necessarily easy 0 they can be easy moderate or difficult. The )uestions are written so that the incorrect answers are plausible distractors based on common errors or misconceptions. misconceptions. The )uestions in this )ui, cover topics mainly from specification sections !iology A %.1.' En,ymes !iology ! "Advancing !iology( %.1.2 3roteins and en,ymes.
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1
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Multiple Choice Questions (MCQ) topic quiz $ answers 1
7hich of the diagrams illustrates the way in which the rate of an en,yme/controlled reaction depends on substrate concentration8
A 9our answer
%
7hen starch and amylase are mi:ed in the presence of iodine solution the blue/blaccolour rapidly disappears. This is due to the formation of which molecule8 "
glucose
%
glycogen
C
sucrose
&
maltose 9our answer
2
;
7hich of the following en,yme groups can catalyse o:idation reactions8 "
phosphorylases
%
isomerases
C
hydrolases
&
dehydrogenases 9our answer
4ersion 1
%
;
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'
The graph below shows an en,yme/controlled reaction. The en,yme concentration is -ept constant.
At concentrations of substrate greater than ' which of the following statements is true8 "
The rate of reaction is limited by en,yme concentration.
%
The rate of reaction tends towards ,ero.
C
The substrate has an inhibitory effect.
&
The products have an inhibitory effect. 9our answer
<
En,ymes differ from inorganic catalysts in that they are highly specific. 7hich property of an en,yme is responsible for this specificity8 "
The insoluble nature of en,ymes.
%
The high molecular mass of en,ymes.
C
The surface configuration of en,ymes.
&
The absence of metallic ions in an en,yme. 9our answer
4ersion 1
A
2
C
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6
=
7hat is the appro:imate temperature coefficient "+ 1$( of an en,yme/controlled reaction8 "
<$
%
1$
C
%
&
1 9our answer
C
9our answer
C
7hich of the en,ymes below catalyses the following reaction8 triglyceride → glycerol + 3 fatty acids
>
"
decarbo:ylase
%
dehydrogenase
C
hydrolase
&
o:idase
uccinic acid dehydrogenase is the en,yme which catalyses the o:idation of succinic acid during cell respiration. ?f malonic acid is added to the system the rate of reaction is reduced. An increase in the substrate concentration succinic acid increases t he rate of reaction again. @sing this information what might be deduced about the action of malonic acid8 "
?t decreases the p# of the system.
%
?t forms a permanent attachment to the active site of the en,yme.
C
?t has a similar molecular configuration to that of succinic acid.
&
?t acts as a coen,yme. 9our answer
4ersion 1
C
?n the following diagram each of the curves Q and represents an en,yme/ controlled reaction in one of the following situations
'
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•
with the en,yme uninhibited
•
with a non/competitive inhibitor
•
with a competitive inhibitor.
7hich curve Q or represents each situation8 uninhibited enzyme
competitive inhibitor added
noncompetitive inhibitor added
"
3
+
R
%
3
R
+
C
R
+
3
&
R
3
+
9our answer
4ersion 1
<
A
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1$
7hich of the following is an e:tracellular en,yme8 "
catalase
%
;BA polymerase
C
-eratin
&
trypsin
Note: Keratin is not on the Biology B specification. lease replace !ith "ibrin.
9our answer
11
?f other conditions were to remain constant which one of the following changes would e:plain a reduced rate of activity in an en,yme/controlled reaction8 "
increase in concentration of end/product
%
increase in substrate concentration
C
increase in en,yme concentration
&
increase in temperature towards the optimum 9our answer
1%
"
a high temperature
%
an e:treme p#
C
heavy metal ions
&
a low temperature ;
7hich type of en,yme catalyses the conversion of a dipeptide into two separate amino acids8 "
decarbo:ylase
%
dehydrogenase
C
hydrolase
&
o:idoreductase 9our answer
4ersion 1
A
7hich one of the following conditions is least li-ely to denature an en,yme8
9our answer
12
;
6
C
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1'
The action of an en,yme depends on the specific structure of its active site. 7hich of these bonds are not important in maintaining the shape of the active site8 "
ionic
%
hydrogen
C
disulfide
&
phosphodiester 9our answer
1<
;
The diagram below represents reactions ta-ing place in a bacterium in which amino acids are produced from other amino acids by the action of specific en,ymes. The numbers */+ refer to different amino acids and the letters , and ' refer to different en,ymes. 7hen an e:cess of amino acid + is added into the bacterium the rate of the
reactions is reduced. 7hat is the cause of this8 "
end product inhibition
%
en,yme denaturation
C
e:cess substrate inhibiting the en,yme
&
positive feedbac9our answer
4ersion 1
=
A
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16
A sample of a starch suspension was tested with iodine solution and the result was a blue/blac- colour. A second sample of the starch suspension was tested with !enedicts reagent and the result was a blue colour. A third sample of the starch suspension was mi:ed with amylase and incubated at 2$ oC for 1$ minutes and then tested with !iuret reagent. 7hat was the resulting colour of the third sample8 "
blue
%
blue/blac-
C
bric- red
&
purple 9our answer
4ersion 1
>
;
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+uestions 1= and 1> refer to the following graph. Curve ' represents the relationship between an en,yme and the concentration of its substrate under optimal conditions and without an inhibitor.
1=
7hich one of the curves " % C or & represents the result when the same e:periment is conducted in the presence of a fi:ed low concentration of a reversible competitive inhibitor8 9our answer
1>
A
7hich one of the curves " % C or & represents the result when the same e:periment is conducted in the presence of a fi:ed low concentration of an irreversible non/competitive inhibitor8 9our answer
1
7hen an en,yme is subDected to temperatures above the optimum it denatures. 7hich of the following bonds are the first to be disrupted by high temperatures8 "
disulfide
%
hydrogen
C
ionic
&
peptide 9our answer
4ersion 1
!
!
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%$
7hich one of the following graphs shows the effect of p# on the reaction velocity of a typical en,yme8 Bote ?n each graph the scale on the : a:is is from p# % to p# 12.
!
9our answer
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4ersion 1
1$
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Multiple Choice Questions (MCQ) topic quiz Enzymes Learner Activity 1
7hich of the diagrams illustrates the way in which the rate of an en,yme/controlled reaction depends on substrate concentration8
9our answer
%
7hen starch and amylase are mi:ed in the presence of iodine solution the blue/blaccolour rapidly disappears. This is due to the formation of which molecule8 "
glucose
%
glycogen
C
sucrose
&
maltose 9our answer
2
7hich of the following en,yme groups can catalyse o:idation reactions8
4ersion 1
"
phosphorylases
%
isomerases
C
hydrolases
&
dehydrogenases
11
5 OCR %$16
9our answer
'
The graph below shows an en,yme/controlled reaction. The en,yme concentration is -ept constant.
At concentrations of substrate greater than ' which of the following statements is true8 "
The rate of reaction is limited by en,yme concentration.
%
The rate of reaction tends towards ,ero.
C
The substrate has an inhibitory effect.
&
The products have an inhibitory effect. 9our answer
<
En,ymes differ from inorganic catalysts in that they are highly specific. 7hich property of an en,yme is responsible for this specificity8 "
The insoluble nature of en,ymes.
%
The high molecular mass of en,ymes.
C
The surface configuration of en,ymes.
&
The absence of metallic ions in an en,yme. 9our answer
4ersion 1
1%
5 OCR %$16
6
7hat is the appro:imate temperature coefficient "+ 1$( of an en,yme/controlled reaction8 "
<$
%
1$
C
%
&
1 9our answer
=
7hich of the en,ymes below catalyses the following reaction8 triglyceride → glycerol + 3 fatty acids "
decarbo:ylase
%
dehydrogenase
C
hydrolase
&
o:idase 9our answer
>
uccinic acid dehydrogenase is the en,yme which catalyses the o:idation of succinic acid during cell respiration. ?f malonic acid is added to the system the rate of reaction is reduced. An increase in the substrate concentration succinic acid increases t he rate of reaction again. @sing this information what might be deduced about the action of malonic acid8 "
?t decreases the p# of the system.
%
?t forms a permanent attachment to the active site of the en,yme.
C
?t has a similar molecular configuration to that of succinic acid.
&
?t acts as a coen,yme. 9our answer
4ersion 1
?n the following diagram each of the curves Q and represents an en,yme/ controlled reaction in one of the following situations
12
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•
with the en,yme uninhibited
•
with a non/competitive inhibitor
•
with a competitive inhibitor.
7hich curve Q or represents each situation8 uninhibited enzyme
competitive inhibitor added
noncompetitive inhibitor added
"
3
+
R
%
3
R
+
C
R
+
3
&
R
3
+
9our answer
4ersion 1
1'
5 OCR %$16
1$
7hich of the following is an e:tracellular en,yme8 "
catalase
%
;BA polymerase
C
-eratin
&
trypsin 9our answer
11
?f other conditions were to remain constant which one of the following changes would e:plain a reduced rate of activity in an en,yme/controlled reaction8 "
increase in concentration of end/product
%
increase in substrate concentration
C
increase in en,yme concentration
&
increase in temperature towards the optimum 9our answer
1%
7hich one of the following conditions is least li-ely to denature an en,yme8 "
a high temperature
%
an e:treme p#
C
heavy metal ions
&
a low temperature 9our answer
12
7hich type of en,yme catalyses the conversion of a dipeptide into two separate amino acids8 "
decarbo:ylase
%
dehydrogenase
C
hydrolase
&
o:idoreductase 9our answer
1'
4ersion 1
The action of an en,yme depends on the specific structure of its active site.
1<
5 OCR %$16
7hich of these bonds are not important in maintaining the shape of the active site8 "
ionic
%
hydrogen
C
disulfide
&
phosphodiester 9our answer
1<
The diagram below represents reactions ta-ing place in a bacterium in which amino acids are produced from other amino acids by the action of specific en,ymes. The numbers */+ refer to different amino acids and the letters , and ' refer to different en,ymes. 7hen an e:cess of amino acid + is added into the bacterium the rate of the
reactions is reduced. 7hat is the cause of this8 "
end product inhibition
%
en,yme denaturation
C
e:cess substrate inhibiting the en,yme
&
positive feedbac9our answer
4ersion 1
16
5 OCR %$16
16
A sample of a starch suspension was tested with iodine solution and the result was a blue/blac- colour. A second sample of the starch suspension was tested with !enedicts reagent and the result was a blue colour. A third sample of the starch suspension was mi:ed with amylase and incubated at 2$ oC for 1$ minutes and then tested with !iuret reagent. 7hat was the resulting colour of the third sample8 "
blue
%
blue/blac-
C
bric- red
&
purple 9our answer
4ersion 1
1=
5 OCR %$16
+uestions 1= and 1> refer to the following graph. Curve ' represents the relationship between an en,yme and the concentration of its substrate under optimal conditions and without an inhibitor.
1=
7hich one of the curves " % C or & represents the result when the same e:periment is conducted in the presence of a fi:ed low concentration of a reversible competitive inhibitor8 9our answer
1>
7hich one of the curves " % C or & represents the result when the same e:periment is conducted in the presence of a fi:ed low concentration of an irreversible non/competitive inhibitor8 9our answer
1
7hen an en,yme is subDected to temperatures above the optimum it denatures. 7hich of the following bonds are the first to be disrupted by high temperatures8 "
disulfide
%
hydrogen
C
ionic
&
peptide 9our answer
4ersion 1
1>
5 OCR %$16
%$
7hich one of the following graphs shows the effect of p# on the reaction velocity of a typical en,yme8
Bote ?n each graph the scale on the : a:is is from p# % to p# 12.
9our answer
4ersion 1
1
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