Plants 9.3 Growth in plants (extra)

Question 1

Explain how regulation in gene expression pattern influence plant growth

Answer 1

• Shoot tips detect light through phototropins
• Shoot apical meristems cause production and phototropins cause movement of auxin
• Auxin is a plant hormone
• Auxin moves by efflux pump action into the nuclei of cells on the dark side/opposite the light side of stem
• Auxin and an auxin receptor in nuclei form complex specific transcriptional repressors of auxin responsive genes are targeted
• Promotes transcription of specific gene
• Genes expression is altered/regulated
• that activates a proton pump
• Proton pump actively transports H+ into spaces of cell wall
• H+ causes pH to decrease
• Hydrogen bonds between cellulose fibers of cell wall break
This causes elongation of cells on side away from light