Required Practical 8: Plant Responses

• What is the main focus of the video discussed in the study material?

  Investigating the effect of light or gravity on the growth of newly germinated seedlings
• Why is this investigation important for triple biology students?


  It is a required practical that helps understand plant growth mechanisms
• What hormone do plants use to control their growth?

  Auxin
• What is the independent variable in the investigation of light intensity on seedlings?


  Light intensity
• What is the dependent variable in the investigation of light intensity on seedlings?


  Height of the seedlings
• What is a control variable in this experiment?


  The volume of water used
• How many mustard seeds are placed in each petri dish?


  10 mustard seeds
• Why is it important to have the same number of seedlings in each dish?

  To ensure that the number of seedlings is a control variable
• What should you do if one dish has more seedlings than the others?


  Remove seedlings from the dishes with more to match the lowest count
• How should the height of each seedling be measured?

  Using a ruler while holding the stems straight
• What are the three different light conditions for the dishes?

  Full sunlight, partial light, and darkness
• How often should the height of the seedlings be measured?


  Every day for at least five consecutive days
• What should be done with the results after the experiment?

  Calculate the mean seedling height and draw diagrams
• What is phototropism?


  The growth of seedlings towards the light source
• Why do seedlings in the dark grow rapidly?


  They are trying to reach the light
• What happens to the leaves of seedlings kept in the dark?


  The leaves become small and yellow
• How does gravity affect the growth of seedlings?


  Chutes grow upwards and roots grow downwards
• What role does auxin play in root growth in response to gravity?


  Auxin inhibits cell growth on the lower side of the root
• Where can students find more questions on this required practical?

  In the vision workbook linked in the video