ORTCITIAEE: Survival and response- Tropism Flashcards
Organisms increase their chance of survival by responding to changes in their environment. pecific growth factors move from growing regions to other tissues, where they regulate growth in response to directional stimuli. explanation of gravitropism and phototropism in flowering plants. Taxes and kineses
What is tropism?
When part of a plant has a directional response to a stimulus.
Plants will either grow _____ or _____ from a stimulus.
Towards or away
When tropism is a directional response to light, this is called _________.
Phototropism
When tropism is a directional response to gravity, this is called _________.
Gravitropism
_____ ______ allows a plant to grow towards a stimulus.
Cell elongation
What chemical controls cell elongation?
IAA
Where in a plant do cells elongate as a response to phototropism?
Shoot tips
Explain how cell elongation occurs as a response to tropism:
- In the shoot tips, IAA is concentrated in cells that are not facing the light.
- This stimulates cell elongation in these cells.
- This causes the shoot tip to bend towards the light
A higher IAA concentration will ______ cell elongation in SHOOT tips.
Stimulate
Where in a plant to cells elongate as a response to gravitropism?
Root tips
Explain how cell elongation occurs as a response to gravitropism:
- In the root tips, IAA is concentrated in cells that are facing gravity.
- This inhibits cell elongation in these cells
- This causes the root tips to bend towards gravity.
A higher IAA concentration will ______ cell elongation in ROOT tips.
Inhibit
IAA is a _____ ______ _______.
Specific growth factor
What are plant growth factors?
Chemicals which regulate plant growth in response to directional stimuli.
