CAIE A-Level Biology A2 15.2.2 Auxin Role in Elongation Growth Questions

There are more than 600 plant species in the genus Ipomoea. Many species are grown for their attractive flowers, and some species are used as crop plants.

Scientists are researching whether abscisic acid can be used in crop treatment to increase yield. Evidence suggests that abscisic acid modifies the effect of auxin on elongation growth in plants.

The passage outlines the role of auxin in elongation growth in plants.

Complete the passage by using the most appropriate scientific terms.

The binding of auxin to receptors causes ...... to be pumped into cell walls.

This activates proteins called expansins, which disrupt the links between ...... microfibrils. The cell walls are then able to expand.