Q25 - Do ABC Transporters Pump Floral Scent Out of Petal Cells?

Theoretical B Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Flowers produce volatile fragrances from their petals to attract pollinators, but only once they have become fertile. Some volatile molecules diffuse through petal-cell (pictured) membranes into the air. The ABC superfamily of transmembrane transporters use ATP to pump substances out of cells. These include multi-drug resistance pumps that export many foreign chemicals from bacterial, plant and cancer cells. To investigate whether ABC transporters pump some volatile fragrances into the air, scientists generated several testable hypotheses.

Figure 1 for Q25: Do ABC Transporters Pump Floral Scent Out of Petal Cells?

Using the information and data, determine which of the statements are true or which are false.

A. An ABC transporter which is most highly expressed in budding flowers, compared to open flowers, is the one involved in fragrance emission.

B. Plant strains which express ABC transporters at high levels in their flowers are more fragrant, compared to strains which express ABC transporters at low levels in their flowers.

C. There is a higher concentration of volatile fragrances inside petal cells when ABC transporters are blocked.

D. Altering ABC transporter function has a greater effect on the emission of small volatile molecules, than large volatile molecules.

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Question reproduced from IBO 2017, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Official answer key & worked solutions