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• Why do scientists use controls?

  • For comparison
  • To check no other variable is affecting the results
• Effect of reduced water to a plant?


  o less water so lower rate of photosynthesis

  • so less glucose produced
  • for respiration
  • so less cellulose produced so fewer cells walls made
  • and fewer amino acids are produced to make new proteins

  o cells lose turgidity
• Effect of reduced magnesium ions to a plant?

  less chlorophyll produced

  lower rate of photosynthesis
• Effect of reduced nitrate ions to a plant?

  fewer proteins made for growth
• Effect of damaged phloem?

  o less transport of sugars to cells

  o for respiration
• Effect of damaged xylem

  • less water transported to cells
  • fewer nitrates reach cells so fewer proteins made for growth
  • fewer magnesium ions reach cells so less chlorophyll produced so lower rate of photosynthesis so less glucose produced