(a) DCPIP is an indicator and can be used to determine the rate of respiration of organisms such
as yeast.
(i) State the category of indicators to which DCPIP belongs.
..................................................................................................................................... [1]
(ii) Describe the colour change that occurs in DCPIP during experiments to determine the
rate of respiration.
..................................................................................................................................... [1]
(b) An investigation was carried out to determine the effect of temperature on the rate of
respiration of yeast.
• A suspension of yeast cells was added to a test‑tube containing glucose solution.
• A further four test‑tubes were set up in the same way.
• One test‑tube was placed in a water‑bath at 10 °C for 5 minutes.
• DCPIP was added to the test‑tube and the time taken for the DCPIP to change colour
was measured.
• The experiment was repeated using the other test‑tubes at 20° C, 30 °C, 40 °C and 50 °C.
The results are shown in Fig. 6.1.
Fig. 2.1 shows the main stages of the Calvin cycle.
(a) State precisely where the Calvin cycle occurs in plant cells.
[1]
(b) Describe how carbon dioxide is fixed in the Calvin cycle.
[2]
(c) Explain how the products of photophosphorylation are used in the Calvin cycle.
[3]
(d) Explain what initially happens to the concentration of RuBP and GP if the supply of
carbon dioxide is reduced.
RuBP
GP
[2]
[Total: 8]
UCLES 2007 9700/4/SP07 final
PPMMTT
Question
Biology
CAIE2023
(a) State what is meant by the term respiratory quotient (RQ).
[1]
(b) (i) Complete the following equation for the aerobic respiration of the respiratory
substrate A.
C H O + 26O + [2]
Question
Biology
CAIE2023
For
Examiner's
Use
(d) Outline how this apparatus is used to measure the rate of oxygen uptake by a known
mass of germinating seeds.
[4]
(e) Explain how the apparatus could be modified to measure the RQ of the germinating
seeds.
[2]
(f) Explain why an increase in temperature from 15 oC to 25 oC will increase the rate of
oxygen uptake in germinating seeds.
[2]
[Total: 15]
UCLES 2007 9700/4/SP07 final [Turn over
PPMMTT
When only neurone X is stimulated, an action potential will occur in the postsynaptic
neurone.
Question
Biology
CAIE2023
When only neurone Y is stimulated, an action potential will occur in the postsynaptic
neurone.
Question
Biology
CAIE2023
The potato plant, Solanum tuberosum, is an important food crop. Crop yield is reduced if the
leaves of the plant are eaten by the larvae (immature stages) of the Colorado beetle, Leptinotarsa
decemlineata.
Crop scientists used recombinant DNA technology to create two genetically modified (GM)
varieties of potato plant. These plants produce proteins that are poisonous to insects.
• GM potato variety A contains two new genes, SN and Bt.
• GM potato variety B contains two new genes, SN and OCII.
The new varieties were tested by having a constant number of Colorado beetle larvae introduced
to the plants at time 0 hours. The number of larvae that were alive after 24, 48 and 72 hours was
recorded. The percentage of the larvae that had died in each time interval was calculated. This
was repeated for potato plants that had not been genetically modified (non-GM).
Table 4.1 shows the percentage of Colorado beetle larvae that had died on the GM potato plant
varieties and on non-GM potato plants.
Table 4.1
percentage of Colorado beetle larvae that had died
type of potato plant
Question
Biology
CAIE2023
carbon dioxide and water.
Table 5.1
respiratory substrate formula number of oxygen molecules
needed for respiration
beta-hydroxybutyric acid C H O 4.5
Question
Biology
CAIE2023
8 3
glucose C H O 6.0
Question
Biology
CAIE2023
6 5
oleic acid C H O 25.5
Question
Biology
CAIE2023
For
Examiner's
Use
Question
Biology
CAIE2023
[2]
[Total: 8]
UCLES 2007 9700/4/SP07 final [Turn over
PPMMTT
Question
Biology
CAIE2023
0.20 0.10
Question
Biology
CAIE2023
cross pollination
Question
Biology
CAIE2023
[4]
[Total: 8]
UCLES 2007 9700/4/SP07 final [Turn over
PPMMTT
Question
Biology
CAIE2023
The potato plant, Solanum tuberosum, is an important food crop. Crop yield is reduced if the
leaves of the plant are eaten by the larvae (immature stages) of the Colorado beetle, Leptinotarsa
decemlineata.
Crop scientists used recombinant DNA technology to create two genetically modified (GM)
varieties of potato plant. These plants produce proteins that are poisonous to insects.
• GM potato variety A contains two new genes, SN and Bt.
• GM potato variety B contains two new genes, SN and OCII.
The new varieties were tested by having a constant number of Colorado beetle larvae introduced
to the plants at time 0 hours. The number of larvae that were alive after 24, 48 and 72 hours was
recorded. The percentage of the larvae that had died in each time interval was calculated. This
was repeated for potato plants that had not been genetically modified (non-GM).
Table 4.1 shows the percentage of Colorado beetle larvae that had died on the GM potato plant
varieties and on non-GM potato plants.
Table 4.1
percentage of Colorado beetle larvae that had died
type of potato plant
Question
Biology
CAIE2023
carbon dioxide and water.
Table 5.1
respiratory substrate formula number of oxygen molecules
needed for respiration
beta-hydroxybutyric acid C H O 4.5
Question
Biology
CAIE2023
8 3
glucose C H O 6.0
Question
Biology
CAIE2023
The fruit fly, Drosophila melanogaster, has autosomal genes for body colour and wing shape.
Gene B/b is involved in the production of body colour:
• B = dominant allele for brown body colour
• b = recessive allele for black body colour.
Gene D/d is involved in wing shape:
• D = dominant allele for straight wing
• d = recessive allele for curved wing.
A dihybrid test cross was carried out between flies heterozygous for body colour and for wing
shape and flies homozygous recessive for body colour and for wing shape.
(a) Table 5.1 shows the number of offspring of each phenotype obtained in the test cross.
Table 5.1
observed expected
phenotype
number number
brown body colour, straight wings 2843
brown body colour, curved wings 855
black body colour, straight wings 842
black body colour, curved wings 2768
Use Table 5.1 to calculate the expected number of each phenotype if the two genes are on
different autosomes. Write your answers in the table. [1]
(b) A chi-squared (χ2) test was carried out to compare the observed results with the results that
would be expected from a dihybrid cross involving genes on different autosomes.
The value of χ2 = 2097.836.
Table 5.2 shows the critical values for the χ2 distribution.
Table 5.2
p value
degrees of
freedom
Yeasts are unicellular organisms from the kingdom Fungi. Saccharomyces cerevisiae is one
species of yeast that can carry out either asexual reproduction by mitosis or sexual reproduction
by meiosis.
Budding in S. cerevisiae is a process where a small daughter cell forms as a bud on the parent
cell. The bud contains a copy of the parent cell nucleus and it eventually separates from the
parent cell to form a new cell.
S. cerevisiae can exist in two forms: haploid cells or diploid cells.
• Haploid cells can be one of two different mating types: a and α.
• Haploid cells can only mate with other haploid cells of the opposite mating type.
Fig. 2.1 shows the life cycle of S. cerevisiae with its asexual and sexual reproductive stages.
Key: a mating type a a α
α
a budding budding
α mating type α
α
a
Question
Biology
CAIE2023
1
a α
α
a
mating
a α
formation of 2
zygote
a α
aα budding
aα
( a) During a sporting event, an athlete carries out aerobic respiration.
Structures and compounds involved in aerobic respiration are listed, 1 to 1 0.
Question
Biology
CAIE2016
hours
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams or graphs.
Do not use staples, paper clips, glue or correction fl uid.
DO NOT WRITE IN ANY BARCODES.
Section A
Answer all questions.
Section B
Answer one question.
Electronic calculators may be used.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
PPMMTT