24. Survival and response

• What is a stimulus

  A detectable change in the internal or external environment
• What is a tropism

  A plants growth response to an external or directional stimulus. Can either be positive or negative
• Phototropism 


  Movement in response to light
• Gravitropism


  Movement in response to gravity
• Hydrotropism

  Movement in response to water
• What is IAA

  an auxin that controls growth of plants
• Where is IAA produced

  Tip of shoot or root
• How does IAA move in a plant

  Diffusion
• IAA in shoots causes

  Elongation
• IAA in roots causes

  Inhibition
• What is a taxis

  Simple directional response in an organism that can be positive or negative
• What is a kinesis

  Non directional response
• What is the CNS

  central nervous system made up of brain and spinal cord
• What is the peripheral nervous system 


  Sensory and motor neurones
• What is a reflex

  Rapid short lived involuntary response to a stimulus
• What is a sensory neurone

  Carries impulse from receptor to cns
• What is motor neurone

  Carries impulse from CNS to effector