2018 A LEVEL BIOLOGY FINAL EXAM ACTUAL QUESTIONS
AND CORRECT ANSWERS ALREADY GRADED A+
GUARANTEED SUCCESS
1. Water moves into the cells/cytoplasm by
osmosis;
2. Cell/cytoplasm gets bigger;
Suggest one way the structure of the chromosome could differ along its length to
result in the stain binding more in some areas.
Differences in base sequences
OR
Differences in histones/interaction with
histones
OR
Differences in condensation/(super)coiling;
What does this result suggest about the difference between the observed and
expected results and what can the scientists therefore conclude?
1. There is a less than 0.05/5% probability
that the difference(s) (between observed
and expected) occurred by chance;
2. Calculated value is greater than critical
value so the null hypothesis can be rejected;
3. (The scientists can conclude that) the
proportion of plants that produce 2n
1
,gametes does change from one breeding
cycle to the next;
Use your knowledge of directional selection to explain the results shown in Table
3.
1. The scientists selected/used for breeding plants
that produced 2n gametes;
2. (So these plants) passed on their alleles (for
production of 2n gametes to the next generation);
3. The frequency of alleles for production of 2n
gametes increased (in the population).
What is a homologous pair of chromosomes?
(Two chromosomes that) carry the same
genes;
Give two ways in which the arrangement of prokaryotic DNA is different from the
arrangement of the human DNA in Figure 1.
(Prokaryotic DNA) is
1. Circular (as opposed to linear);
2. Not associated with proteins/histones ;
3. Only one molecule/piece of DNA
OR
present as plasmids;
Describe the method the student would have used to obtain the results in Figure 3.
Start after all of the cubes of potato have been cut. Also consider variables he
should have controlled.
1. Method to ensure all cut surfaces of the eight
2
,cubes are exposed to the sucrose solution;
2. Method of controlling temperature;
3. Method of drying cubes before measuring;
4. Measure mass of cubes at stated time intervals;
What is meant by 'species richness'?
(A measure of) the number of (different) species in
a community;
In each case, suggest one consideration the scientists had taken into account to
make sure their method
[2 marks]
1. was ethical.
2. allowed them to identify accurately the species to which each belonged.
1. Must not harm the bees
OR
Must allow the bee to be released
unchanged;
2. Must allow close examination
OR
Use a key (to identify the species);
Suggest and explain two ways in which the scientists could have improved the
method used for data collection in this investigation.
1. Collect at more times of the year so
more points on graph/better line (of
best fit) on graph;
2. Counted number of individuals in each
species so that they could calculate
3
, index of diversity;
3. Collected from more sites/more years
to increase accuracy of (mean) data;
Three of the bee species collected in the farmland areas were Peponapis pruinosa,
Andrena chlorogaster and Andrena piperi.
What do these names suggest about the evolutionary relationships between these
bee species? Explain your answer.
1. A. chlorogaster and A. piperi are more
closely related (to each other than to
P. pruinosa);
2. Because they are in the same genus;
Formation of an enzyme-substrate complex increases the rate of reaction.
Explain how.
1. Reduces activation energy;
2. Due to bending bonds
OR
Without enzyme, very few substrates have
sufficient energy for reaction;
Suggest a reason for the difference in the results shown in Figure 5 with and
without lyxose.
1. (Binding) alters the tertiary structure
of the enzyme ;
2. (This causes) active site to change
(shape);
3. (So) More (successful) E-S
4
AND CORRECT ANSWERS ALREADY GRADED A+
GUARANTEED SUCCESS
1. Water moves into the cells/cytoplasm by
osmosis;
2. Cell/cytoplasm gets bigger;
Suggest one way the structure of the chromosome could differ along its length to
result in the stain binding more in some areas.
Differences in base sequences
OR
Differences in histones/interaction with
histones
OR
Differences in condensation/(super)coiling;
What does this result suggest about the difference between the observed and
expected results and what can the scientists therefore conclude?
1. There is a less than 0.05/5% probability
that the difference(s) (between observed
and expected) occurred by chance;
2. Calculated value is greater than critical
value so the null hypothesis can be rejected;
3. (The scientists can conclude that) the
proportion of plants that produce 2n
1
,gametes does change from one breeding
cycle to the next;
Use your knowledge of directional selection to explain the results shown in Table
3.
1. The scientists selected/used for breeding plants
that produced 2n gametes;
2. (So these plants) passed on their alleles (for
production of 2n gametes to the next generation);
3. The frequency of alleles for production of 2n
gametes increased (in the population).
What is a homologous pair of chromosomes?
(Two chromosomes that) carry the same
genes;
Give two ways in which the arrangement of prokaryotic DNA is different from the
arrangement of the human DNA in Figure 1.
(Prokaryotic DNA) is
1. Circular (as opposed to linear);
2. Not associated with proteins/histones ;
3. Only one molecule/piece of DNA
OR
present as plasmids;
Describe the method the student would have used to obtain the results in Figure 3.
Start after all of the cubes of potato have been cut. Also consider variables he
should have controlled.
1. Method to ensure all cut surfaces of the eight
2
,cubes are exposed to the sucrose solution;
2. Method of controlling temperature;
3. Method of drying cubes before measuring;
4. Measure mass of cubes at stated time intervals;
What is meant by 'species richness'?
(A measure of) the number of (different) species in
a community;
In each case, suggest one consideration the scientists had taken into account to
make sure their method
[2 marks]
1. was ethical.
2. allowed them to identify accurately the species to which each belonged.
1. Must not harm the bees
OR
Must allow the bee to be released
unchanged;
2. Must allow close examination
OR
Use a key (to identify the species);
Suggest and explain two ways in which the scientists could have improved the
method used for data collection in this investigation.
1. Collect at more times of the year so
more points on graph/better line (of
best fit) on graph;
2. Counted number of individuals in each
species so that they could calculate
3
, index of diversity;
3. Collected from more sites/more years
to increase accuracy of (mean) data;
Three of the bee species collected in the farmland areas were Peponapis pruinosa,
Andrena chlorogaster and Andrena piperi.
What do these names suggest about the evolutionary relationships between these
bee species? Explain your answer.
1. A. chlorogaster and A. piperi are more
closely related (to each other than to
P. pruinosa);
2. Because they are in the same genus;
Formation of an enzyme-substrate complex increases the rate of reaction.
Explain how.
1. Reduces activation energy;
2. Due to bending bonds
OR
Without enzyme, very few substrates have
sufficient energy for reaction;
Suggest a reason for the difference in the results shown in Figure 5 with and
without lyxose.
1. (Binding) alters the tertiary structure
of the enzyme ;
2. (This causes) active site to change
(shape);
3. (So) More (successful) E-S
4
