LATEST UPDATED 2024 & 2025 IB BIOLOGY
PAPER 2 QUESTION & VERIFIED ANSWERS
ALREADY GRADED A+
(a) Sickle cell anemia is due to a single base substitution in DNA.
outline how this translates into the production of an abnormal
hemoglobin molecule bycompleting the spaces labelled I, II and III.
- RIGHT ANSWER -
I: GUG
II: CAC ✔
III: Val/valine ✔
Analyse the effect of NPA on the formation of roots. - RIGHT
ANSWER -NPA decreased the length per root by more than half.
NPA inhibited the formation of roots.
Based on all the data presented and your knowledge of auxin,
discuss the pattern of auxin production and distribution in the
leaves and the possible relationship to root formation in leafy
cuttings of Petunia hybrida. - RIGHT ANSWER -
a. L1 has the highest concentration of auxin so it is the main
source of auxin
b. as leaves age, they «appear to» decrease the production of
auxin
c. High concentration of auxin in the stem base promotes root
formation.
,Based on the data and your biological knowledge, suggest how the
infection could lead to premature death in a bat. - RIGHT ANSWER
-1. energy needed to raise body temperature / lost during
temperature spikes ✔
2. (more) heat loss/hypothermia (in winter/cold weather
3. bats die/starve if fat/energy/food stores used up
Birds, bats and humans are all vertebrates with pentadactyl limbs.
Birds and bats use their forelimbs to fly whereas humans can use
them to lift and manipulate objects.
Outline how the bird, bat and human forelimb can be used to
illustrate the concept of homologous structures. - RIGHT ANSWER
-a. (homologous structures have evolved) from a common ancestor
b. different uses/functions
C. nemoralis is a mollusc.
Identify two external features that distinguish this snail from an
arthropod.
- RIGHT ANSWER -
b. shell (versus exoskeleton in arthropods) ✔
c. muscular foot (which arthropods do not have) ✔
Calculate the difference in the concentration of auxin found in L1
and L6. - RIGHT ANSWER -45 pmolg^-1
,Calculate the difference in the mean leaf area of L6 at the start of
stage 4 between the leaves of plants grown in long days and short
days. - RIGHT ANSWER -130 - 85 = 45mm^2
Calculate the percentage decline in the mean number of M.
lucifugus flights for 2009 when compared to 2008. - RIGHT
ANSWER -..14 (% decline)
Calculate the total number of M. lucifugus fl ights that were
recorded in the summer of 2007 - RIGHT ANSWER -(32 × 79) = 2528
Cells go through a repeating cycle of events in growth regions
such as plant root tips and animal embryos. Outline this cell cycle.
- RIGHT ANSWER -
a. mitosis is the division of a nucleus to produce two genetically
identical daughter nuclei
b. consists of four phases: prophase, metaphase, anaphase,
telophase
c. cytokinesis occurs after mitosis
d. interphase is the metabolically active phase between cell
divisions
e. the interphase consists of the S phase, G1 and G2
f. DNA replicates in the S phase
g. cell growth
, Compare and contrast the changes in auxin concentration in the
stem base over time for the control and NPA-treated cuttings. -
RIGHT ANSWER -Both decrease up to 6 hours initially.
After 6 hours, control increases while NPA treated continues to
fall.Compare and contrast the changes in urea excretion in the
mouth with the changes in urea excretion in the kidney when a
turtle emerges from the water. - RIGHT ANSWER -
a. both higher on emergence with turtle out of water
b. both increased by 0.66 «µmol−1 g−1 when turtle emerges from
water»
d. urea excretion by mouth greater than kidney out of water,
despite larger % increase in kidney excretion
Compare and contrast the location of ATP synthase and the
movement of protons
during aerobic cell respiration and photosynthesis. - RIGHT
ANSWER -
a) location of ATP synthase
cristae/inner mitochondrial membrane versus thylakoid
membranes ✔
b) movement of protons
protons moved/pumped as a result of electron flow/electron
transport in both ✔
Compare the pattern of GH3 transcription with the pattern of
auxin concentration
PAPER 2 QUESTION & VERIFIED ANSWERS
ALREADY GRADED A+
(a) Sickle cell anemia is due to a single base substitution in DNA.
outline how this translates into the production of an abnormal
hemoglobin molecule bycompleting the spaces labelled I, II and III.
- RIGHT ANSWER -
I: GUG
II: CAC ✔
III: Val/valine ✔
Analyse the effect of NPA on the formation of roots. - RIGHT
ANSWER -NPA decreased the length per root by more than half.
NPA inhibited the formation of roots.
Based on all the data presented and your knowledge of auxin,
discuss the pattern of auxin production and distribution in the
leaves and the possible relationship to root formation in leafy
cuttings of Petunia hybrida. - RIGHT ANSWER -
a. L1 has the highest concentration of auxin so it is the main
source of auxin
b. as leaves age, they «appear to» decrease the production of
auxin
c. High concentration of auxin in the stem base promotes root
formation.
,Based on the data and your biological knowledge, suggest how the
infection could lead to premature death in a bat. - RIGHT ANSWER
-1. energy needed to raise body temperature / lost during
temperature spikes ✔
2. (more) heat loss/hypothermia (in winter/cold weather
3. bats die/starve if fat/energy/food stores used up
Birds, bats and humans are all vertebrates with pentadactyl limbs.
Birds and bats use their forelimbs to fly whereas humans can use
them to lift and manipulate objects.
Outline how the bird, bat and human forelimb can be used to
illustrate the concept of homologous structures. - RIGHT ANSWER
-a. (homologous structures have evolved) from a common ancestor
b. different uses/functions
C. nemoralis is a mollusc.
Identify two external features that distinguish this snail from an
arthropod.
- RIGHT ANSWER -
b. shell (versus exoskeleton in arthropods) ✔
c. muscular foot (which arthropods do not have) ✔
Calculate the difference in the concentration of auxin found in L1
and L6. - RIGHT ANSWER -45 pmolg^-1
,Calculate the difference in the mean leaf area of L6 at the start of
stage 4 between the leaves of plants grown in long days and short
days. - RIGHT ANSWER -130 - 85 = 45mm^2
Calculate the percentage decline in the mean number of M.
lucifugus flights for 2009 when compared to 2008. - RIGHT
ANSWER -..14 (% decline)
Calculate the total number of M. lucifugus fl ights that were
recorded in the summer of 2007 - RIGHT ANSWER -(32 × 79) = 2528
Cells go through a repeating cycle of events in growth regions
such as plant root tips and animal embryos. Outline this cell cycle.
- RIGHT ANSWER -
a. mitosis is the division of a nucleus to produce two genetically
identical daughter nuclei
b. consists of four phases: prophase, metaphase, anaphase,
telophase
c. cytokinesis occurs after mitosis
d. interphase is the metabolically active phase between cell
divisions
e. the interphase consists of the S phase, G1 and G2
f. DNA replicates in the S phase
g. cell growth
, Compare and contrast the changes in auxin concentration in the
stem base over time for the control and NPA-treated cuttings. -
RIGHT ANSWER -Both decrease up to 6 hours initially.
After 6 hours, control increases while NPA treated continues to
fall.Compare and contrast the changes in urea excretion in the
mouth with the changes in urea excretion in the kidney when a
turtle emerges from the water. - RIGHT ANSWER -
a. both higher on emergence with turtle out of water
b. both increased by 0.66 «µmol−1 g−1 when turtle emerges from
water»
d. urea excretion by mouth greater than kidney out of water,
despite larger % increase in kidney excretion
Compare and contrast the location of ATP synthase and the
movement of protons
during aerobic cell respiration and photosynthesis. - RIGHT
ANSWER -
a) location of ATP synthase
cristae/inner mitochondrial membrane versus thylakoid
membranes ✔
b) movement of protons
protons moved/pumped as a result of electron flow/electron
transport in both ✔
Compare the pattern of GH3 transcription with the pattern of
auxin concentration
