Plants response

• What is the definition of tropism in plants?

  Tropism is a growth response by a plant.
• What is a positive response in tropism?

  A positive response is growing towards the stimulus.
• What is a negative response in tropism?

  A negative response is growing away from the stimulus.
• What is phototropism?

  Phototropism is a response in which a plant grows towards or away from light.
• How does a plant shoot respond to light in terms of phototropism?

  A plant shoot shows positive phototropism.
• What is gravitropism (or geotropism)?

  Gravitropism is a response in which a plant grows towards or away from gravity.
• How does the shoot respond to gravity?

  The shoot shows negative gravitropism.
• How does the root respond to gravity?

  The root shows positive gravitropism.
• What is the role of the receptor in plant responses?

  The receptor is the tip of the shoot, sensitive to light.
• What is the role of the effector in plant responses?

  The effector is the part of the shoot that responds to the stimulus.
• How do the receptor and effector communicate in plants?

  They communicate with the plant hormone, auxin.
• What is auxin?

  Auxin is a plant hormone.
• What effect does auxin have on plant cells?

  Auxin causes cells to grow (elongate).
• Where is auxin made in the plant?

  Auxin is made by cells in the shoot tip.
• How does auxin move in the plant?

  Auxin diffuses downwards.

  
• What happens when light shines evenly on the shoot?

  Auxin is distributed evenly, and all cells grow at the same rate.

  
• What happens when light shines from one side of the shoot?

  Auxin concentrates on the shady side, making those cells grow faster.

  
• What is the result of auxin concentration on the shady side of the shoot?

  The shoot bends towards the light.