Zadanie 1a
(i) Distinguish the structure of a green leaf cell from that of a typical fungal cell. (ii) Distinguish a plant nuclear chromosome from a typical bacterial chromosome.
Biology HL Paper 1B, May 2026, TZ3
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
W bazie 15 zadań z tego arkusza, razem 35 punktów, każde z kluczem i schematem punktowania. Najwięcej zadań sprawdza: Planning a biological investigation (3), Tumour behaviour and the mitotic index (2), Evaluating biological evidence and methods (2).
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Dodaj cały arkusz do zestawuZadanie 1b
A student prepares stained squash mounts from a young garlic root to examine cell division. (i) Outline why a stain is used. (ii) Describe how to calculate a reliable mitotic index for the tissue.
Zadanie 1c
In a model tumour-culture experiment, comparable tissue samples are randomly allocated to four treatments: neither compound, P alone, Q alone, or P with Q. After the same incubation period, mitotic indices are measured. Error bars represent standard…
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Zadanie 2a
Outline why the tissue discs should be equal in size.
Zadanie 2b
Describe how the bath temperature could be checked during each incubation to establish that it stayed constant.
Zadanie 2c
Outline one reason for the independent repeats at each temperature.
Zadanie 2d
The mean results are shown. Use membrane structure to explain the relationship.
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Zadanie 2e
A second group instead compares each solution by eye with five reference dilutions labelled 1 (palest) to 5 (darkest). Suggest two advantages of a colorimeter over this visual scale.
Zadanie 3a
Explain why respiration moves the marker to the left, towards the seed chamber.
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Zadanie 3b
After a run, the student opens the tap and pushes air from the syringe into the apparatus. Outline how this permits a repeat reading.
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Zadanie 3c
In a two-hour run, the marker travels 40 mm through a capillary of internal radius 0.60 mm. Calculate the oxygen uptake rate in mm³ h⁻¹ to two decimal places. Use V = πr2l with π = 3.14.
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Zadanie 3d
A control contains the same mass of inert plastic beads instead of germinating seeds. Outline its purpose.
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Zadanie 3e
Explain ATP synthesis by chemiosmosis in aerobic respiration.
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Zadanie 4a
An invented time-scaled tree compares ten related beetle species. (i) Identify the two species with the most recent divergence and give a reason. (ii) Suggest why comparing DNA base sequences can distinguish relationships that are missed by comparing amino…
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Zadanie 4b
A model test cross investigates two autosomal loci in fruit flies. D (dark body) is dominant to d (pale body), and K (long wing) is dominant to k (short wing). A DdKk fly is crossed with ddkk. (i) Calculate the expected number for each phenotype under…
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