Summary
Plants use electrical signals and hormones to coordinate their responses to the environment. The Venus flytrap uses electrical communication to close its trap when sensory hairs are stimulated. Auxin promotes elongation growth by acidifying cell walls, allowing them to stretch. Gibberellin plays a crucial role in the germination of barley by stimulating enzyme production.
- Venus Flytrap — a carnivorous plant that uses electrical signals to close its trap. Example: When a fly touches the sensory hairs, action potentials cause the trap to close.
- Auxin — a plant hormone that promotes cell elongation by lowering pH in cell walls. Example: Auxin causes proton pumps to acidify cell walls, allowing cells to expand.
- Gibberellin — a plant hormone that aids in seed germination by activating enzymes. Example: Gibberellin stimulates amylase production, which breaks down starch into sugars for the growing embryo.
Exam Tips
Key Definitions to Remember
- Venus Flytrap
- Auxin
- Gibberellin
Common Confusions
- Confusing the role of auxin with that of gibberellin
- Misunderstanding how electrical signals work in the Venus flytrap
Typical Exam Questions
- How does the Venus flytrap close its trap? Action potentials triggered by sensory hairs cause the trap to close.
- What role does auxin play in plant growth? Auxin promotes cell elongation by acidifying cell walls.
- How does gibberellin affect barley germination? Gibberellin stimulates enzyme production that breaks down starch into sugars.
What Examiners Usually Test
- Understanding of how plant hormones regulate growth
- Mechanism of electrical communication in the Venus flytrap