CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
Workbook answers
endoplasmic reticulum ; packages
Chapter 1 proteins ; processes proteins/adds sugar
chains to proteins ; produces,
Exam-style questions lysosomes/vesicles containing
1 a proteins for
Feature Prokaryotic Eukaryotic
export from cell ; [max 2]
cell cell
cell surface ✓ ✓ [Total: 10]
membrane 3 a i to slow down (metabolic) reactions
nucleus ✗ ✓ ;
ribosomes ✓ ✓ [1] ii t o keep the pH constant ; to prevent
mitochondria ✗ ✓ denaturation of enzymes ; [2]
1 chloroplasts ✗ ✓ iii to ensure no gain or loss of
mark for water by organelles which could disrupt
each correct row [5] their structure / activity ;
[2]
b s urrounded by protein coat ; containing
DNA or RNA ; [2] b ribosomes are very small / have a lower mass than
other organelles ; [1] c i P and Q ; [1] ii P, Q and R
[Total: 7]
; [1]
2 a transmission electron microscope [1]
d chloroplasts ; they have a similar
b A, B, C, E, G
size and mass to mitochondria ; [2]
5 correct = 3 marks ; ; ;
[Total: 10]
4 correct = 2 marks ;
; 3 correct = 1 mark ; 4 a transmission electron microscope ; has
high resolution / example of detail that
less than 3 correct = 0 marks.
can be seen ; [2] b mitochondrion ; [1] c
I f any other letter is given, subtract
one mark for each incorrect letter. [3] i l ength XY in micrograph = 50 mm =
c i B (mitochondrion – no 50 000 µm ; [1]
mark) producing ATP ; by so actual size = 50 000 ÷ 12 500 =
aerobic 4.0 µm ; [1]
respiration ; [2] [1] ii t o speed
ii E (nuclear membrane – no mark) up the absorption of (digested)
keeps
DNA/chromosomes inside the nutrients from the small intestine ; for
nucleus ; allows RNA / ribosomes to example, of absorbed nutrient (glucose /
pass from nucleus to cytoplasm ; amino acids / water, etc.) ; for example,
allows proteins / nucleotides / ATP to of mechanism of absorption (diffusion /
pass from cytoplasm to nucleus ; facilitated diffusion / active transport) ;
[max 2] reference to membranebound digestive
enzymes on the surfaces of the microvilli
iii G (Golgi body – no mark) ; [max 2]
receives [Total: 8]
proteins made on
,CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
1 Cambridge International AS & A Level Biology – Jones & Parkin © Cambridge University Press 2020 Exam-style questions and sample
answers have been written by the authors. In examinations, the way marks are awarded may be different.
Workbook answers
Chapter 2
Exam-style questions
1 a
Hydrogen bond Disulfide bond Ionic bond α(1,4) glycosidic bond
found in the tertiary ✗ ✗ ✗
structure of a protein
found in amylose ✗
found in cellulose ✗
found in the secondary ✗
structure of a protein
1 mark for each correct row D sucrose and – – +
[4] b i correct C–N bond amylase
1 mark for each correct row [3]
drawn ; water molecule
released ; [2] ii
condensation ; [1]
[Total: 7]
2 a tertiary / 3° ; [1] b
disulfide bonds break ; tertiary structure
changes / shape changes / denaturation occurs ; 1
active site shape changes ;
substrate no longer fits ; [4] b Heat with Benedict’s reagent ; red /
orange / green colour indicates glucose
[Total: 5] is present ; heat new sample with
3 a hydrochloric acid, carry out Benedict’s
Tube Contents Iodine Benedict’s Biuret test ; use same volume of solution ;
test test test higher level of
precipitate / more intense colour indicates
A starch and – + + sucrose ; [max 4]
amylase
[Total: 7]
B starch and + – +
4 a i glucose and fructose ;
sucrase
C sucrose and – + + [1] ii c orrect glucose
sucrase (with OH) ; correct
,CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
fructose (with OH) ; [2] iii hydrolysis ; 2
[1]
b i c ellulose labelled on cell wall ;
starch
labelled on grains ; [2]
ii β -glucose ; every other strand
rotated 180° ; long, straight
chains ; hydrogen bonds
between molecules ; reference
to microfibrils ; high tensile
strength ; allows water to pass
through ; [max 4]
iii (glucose is) more reactive ;
more soluble ; causes osmotic
effects ; [3]
[Total: 13] 5 a g rind up ; dissolve
in ethanol and add water ; emulsion formed indicates
lipids ;
[3]
b correct glycerol ; three correct fatty acids ;
[2] c higher saturation increases melting
point ; stearic acid is saturated ; oleic
acid is monounsaturated ; lauric acid is
polyunsaturated ; reference to C=C
bonds ; C=C bonds cause ‘kinks’ ;
molecules can not form lattice easily ;
[max 4]
[Total: 9]
6 a i 2
H2NNH [1]
ii proline would be on inside
/ hydrophobic area ; tertiary structure
changes / shape changes ; no longer
able to bind other molecules ;
[3]
b l ot of secondary structure ; a-helix ; held together
by hydrogen bonds ; high tensile strength ;
[max 3]
[Total: 7]
, CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
Exam-style questions and sample answers have been written by the authors. In examinations, the way marks are awarded may be
different.
Workbook answers
[Total: 13] 2 a this distinguishes
Chapter 3 it from CO2 that has not been produced by urease
activity ; [1]
Exam-style questions
1 a t ake samples of the reacting b diffuses into the blood (from the
mixture at set time intervals ; add iodine stomach) ; dissolves in blood plasma ;
solution ; note the depth of blue-black transported to lungs in named blood
colour using a colorimeter / colour standards vessels ; diffuses from blood into alveoli
; the more quickly the blue-black colour (and is breathed out) ; [max 3]
disappears the greater the rate of activity ; c 13
c hange in CO2 always higher for A than B
[max 3] ; A reaches peak of 21 a.u. but B never above 0 ; A
rises until 20 minutes then falls but B oscillates /
b i optimum pH is about 5.2 to 5.4, where falls throughout ;
activity of the amylase is about 152 arbitrary [max 2]
units ; activity is 0 at pH 3
and pH 10 ; [2] d this is a non-invasive procedure / quick
and easy to do ; [1]
ii decreases or increases of
[Total: 7]
pH below or above the optimum affect
the hydrogen and ionic bonds ; so the 3 a activity of immobilised pectinase always higher
shape of the active site is lost and the than that of free pectinase ; immobilised
enzyme can no longer bind with its falls to minimum of 44% of activity before
substrate ; the further the pH is from the heating, but free falls to 0 ; immobilised
optimum, the more bonds are broken still has activity after being exposed heated
and the more the shape is lost ; for 60 minutes, but free has no activity after
[3] 30 minutes ; use of manipulated
comparative figures, for example, after 10
c i as temperature increases, the rate of activity minutes activity of
of the enzyme increases ; the fastest rate of immobilised enzyme is 1.6 times greater
reaction occurs at a temperature of 90 °C ; than that of free enzyme ; [max 3]
temperature appears to affect the optimum pH,
b temperature (of the reacting
which is lower at a temperature of
mixture) ; concentration of enzyme ;
37 °C than at 90 °C ; [max 2]
concentration
ii (The optimum temperature must of substrate ; pH ; [max 2] c u sing
be somewhere around 90 °C. )
immobilised pectinase allows
carry out the reaction at a treatment of the fruit / fruit juice, to take
constant pH of 5.5 ; at a range of place at higher temperatures ; could mean
temperatures from about 80 to 100 °C ; a that juice, extraction / clarification, takes
suitable interval would be 2 °C / place faster (because higher temperatures
experiments would be carried out at 80, can be used) ; [2] d enzyme can be
82, 84 °C reused many times (reducing costs of purchasing
and so on ; do three repeats for each enzyme) ; no contamination of product with the
temperature ; [max 3] enzyme (reducing costs of purification) ; (ignore
references to cost alone) [2]
[Total: 9]
Workbook answers
endoplasmic reticulum ; packages
Chapter 1 proteins ; processes proteins/adds sugar
chains to proteins ; produces,
Exam-style questions lysosomes/vesicles containing
1 a proteins for
Feature Prokaryotic Eukaryotic
export from cell ; [max 2]
cell cell
cell surface ✓ ✓ [Total: 10]
membrane 3 a i to slow down (metabolic) reactions
nucleus ✗ ✓ ;
ribosomes ✓ ✓ [1] ii t o keep the pH constant ; to prevent
mitochondria ✗ ✓ denaturation of enzymes ; [2]
1 chloroplasts ✗ ✓ iii to ensure no gain or loss of
mark for water by organelles which could disrupt
each correct row [5] their structure / activity ;
[2]
b s urrounded by protein coat ; containing
DNA or RNA ; [2] b ribosomes are very small / have a lower mass than
other organelles ; [1] c i P and Q ; [1] ii P, Q and R
[Total: 7]
; [1]
2 a transmission electron microscope [1]
d chloroplasts ; they have a similar
b A, B, C, E, G
size and mass to mitochondria ; [2]
5 correct = 3 marks ; ; ;
[Total: 10]
4 correct = 2 marks ;
; 3 correct = 1 mark ; 4 a transmission electron microscope ; has
high resolution / example of detail that
less than 3 correct = 0 marks.
can be seen ; [2] b mitochondrion ; [1] c
I f any other letter is given, subtract
one mark for each incorrect letter. [3] i l ength XY in micrograph = 50 mm =
c i B (mitochondrion – no 50 000 µm ; [1]
mark) producing ATP ; by so actual size = 50 000 ÷ 12 500 =
aerobic 4.0 µm ; [1]
respiration ; [2] [1] ii t o speed
ii E (nuclear membrane – no mark) up the absorption of (digested)
keeps
DNA/chromosomes inside the nutrients from the small intestine ; for
nucleus ; allows RNA / ribosomes to example, of absorbed nutrient (glucose /
pass from nucleus to cytoplasm ; amino acids / water, etc.) ; for example,
allows proteins / nucleotides / ATP to of mechanism of absorption (diffusion /
pass from cytoplasm to nucleus ; facilitated diffusion / active transport) ;
[max 2] reference to membranebound digestive
enzymes on the surfaces of the microvilli
iii G (Golgi body – no mark) ; [max 2]
receives [Total: 8]
proteins made on
,CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
1 Cambridge International AS & A Level Biology – Jones & Parkin © Cambridge University Press 2020 Exam-style questions and sample
answers have been written by the authors. In examinations, the way marks are awarded may be different.
Workbook answers
Chapter 2
Exam-style questions
1 a
Hydrogen bond Disulfide bond Ionic bond α(1,4) glycosidic bond
found in the tertiary ✗ ✗ ✗
structure of a protein
found in amylose ✗
found in cellulose ✗
found in the secondary ✗
structure of a protein
1 mark for each correct row D sucrose and – – +
[4] b i correct C–N bond amylase
1 mark for each correct row [3]
drawn ; water molecule
released ; [2] ii
condensation ; [1]
[Total: 7]
2 a tertiary / 3° ; [1] b
disulfide bonds break ; tertiary structure
changes / shape changes / denaturation occurs ; 1
active site shape changes ;
substrate no longer fits ; [4] b Heat with Benedict’s reagent ; red /
orange / green colour indicates glucose
[Total: 5] is present ; heat new sample with
3 a hydrochloric acid, carry out Benedict’s
Tube Contents Iodine Benedict’s Biuret test ; use same volume of solution ;
test test test higher level of
precipitate / more intense colour indicates
A starch and – + + sucrose ; [max 4]
amylase
[Total: 7]
B starch and + – +
4 a i glucose and fructose ;
sucrase
C sucrose and – + + [1] ii c orrect glucose
sucrase (with OH) ; correct
,CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
fructose (with OH) ; [2] iii hydrolysis ; 2
[1]
b i c ellulose labelled on cell wall ;
starch
labelled on grains ; [2]
ii β -glucose ; every other strand
rotated 180° ; long, straight
chains ; hydrogen bonds
between molecules ; reference
to microfibrils ; high tensile
strength ; allows water to pass
through ; [max 4]
iii (glucose is) more reactive ;
more soluble ; causes osmotic
effects ; [3]
[Total: 13] 5 a g rind up ; dissolve
in ethanol and add water ; emulsion formed indicates
lipids ;
[3]
b correct glycerol ; three correct fatty acids ;
[2] c higher saturation increases melting
point ; stearic acid is saturated ; oleic
acid is monounsaturated ; lauric acid is
polyunsaturated ; reference to C=C
bonds ; C=C bonds cause ‘kinks’ ;
molecules can not form lattice easily ;
[max 4]
[Total: 9]
6 a i 2
H2NNH [1]
ii proline would be on inside
/ hydrophobic area ; tertiary structure
changes / shape changes ; no longer
able to bind other molecules ;
[3]
b l ot of secondary structure ; a-helix ; held together
by hydrogen bonds ; high tensile strength ;
[max 3]
[Total: 7]
, CAMBRIDGE INTERNATIONAL AS & A LEVEL BIOLOGY: WORKBOOK
Exam-style questions and sample answers have been written by the authors. In examinations, the way marks are awarded may be
different.
Workbook answers
[Total: 13] 2 a this distinguishes
Chapter 3 it from CO2 that has not been produced by urease
activity ; [1]
Exam-style questions
1 a t ake samples of the reacting b diffuses into the blood (from the
mixture at set time intervals ; add iodine stomach) ; dissolves in blood plasma ;
solution ; note the depth of blue-black transported to lungs in named blood
colour using a colorimeter / colour standards vessels ; diffuses from blood into alveoli
; the more quickly the blue-black colour (and is breathed out) ; [max 3]
disappears the greater the rate of activity ; c 13
c hange in CO2 always higher for A than B
[max 3] ; A reaches peak of 21 a.u. but B never above 0 ; A
rises until 20 minutes then falls but B oscillates /
b i optimum pH is about 5.2 to 5.4, where falls throughout ;
activity of the amylase is about 152 arbitrary [max 2]
units ; activity is 0 at pH 3
and pH 10 ; [2] d this is a non-invasive procedure / quick
and easy to do ; [1]
ii decreases or increases of
[Total: 7]
pH below or above the optimum affect
the hydrogen and ionic bonds ; so the 3 a activity of immobilised pectinase always higher
shape of the active site is lost and the than that of free pectinase ; immobilised
enzyme can no longer bind with its falls to minimum of 44% of activity before
substrate ; the further the pH is from the heating, but free falls to 0 ; immobilised
optimum, the more bonds are broken still has activity after being exposed heated
and the more the shape is lost ; for 60 minutes, but free has no activity after
[3] 30 minutes ; use of manipulated
comparative figures, for example, after 10
c i as temperature increases, the rate of activity minutes activity of
of the enzyme increases ; the fastest rate of immobilised enzyme is 1.6 times greater
reaction occurs at a temperature of 90 °C ; than that of free enzyme ; [max 3]
temperature appears to affect the optimum pH,
b temperature (of the reacting
which is lower at a temperature of
mixture) ; concentration of enzyme ;
37 °C than at 90 °C ; [max 2]
concentration
ii (The optimum temperature must of substrate ; pH ; [max 2] c u sing
be somewhere around 90 °C. )
immobilised pectinase allows
carry out the reaction at a treatment of the fruit / fruit juice, to take
constant pH of 5.5 ; at a range of place at higher temperatures ; could mean
temperatures from about 80 to 100 °C ; a that juice, extraction / clarification, takes
suitable interval would be 2 °C / place faster (because higher temperatures
experiments would be carried out at 80, can be used) ; [2] d enzyme can be
82, 84 °C reused many times (reducing costs of purchasing
and so on ; do three repeats for each enzyme) ; no contamination of product with the
temperature ; [max 3] enzyme (reducing costs of purification) ; (ignore
references to cost alone) [2]
[Total: 9]
