Answer:
proteins called expansins
Explanation:
The complete question is :
According to the acid-growth hypothesis, auxin causes increased acidity in cell walls, which then activates ____ that disrupt(s) bonds between cellulose microfibrils, allowing cell expansion.
a. a membrane potential
b. an mRNA
c. AUX1 transporters
d. K+ ions
e. proteins called expansins
- The acid growth hypothesis explains the growth of cells and organs in the plants.
- According to this hypothesis, the plant hormone auxin causes induction of the H+ proton extrusion into the apoplast which leads to the activation of expansin which a pH-sensitive protein.
- Expansin is responsible for wall stretching and relaxation and causes hydrolysis of hydrogen bonds and thus helps in cell expansion.
