Photosynthesis limiting factors

HideShow resource information
View mindmap
  • Photoynthesis - Limiting factors
    • Key factors include: LIGHT intensity + quality, CARBON DIOXIDE concentration, TEMPERATURE, WATER, NUTRIENTS.
    • Law of limiting factors:
      • When a process is affected by a number of factors, the factor in the SHORTEST SUPPLY at a given time determines the overall RATE of the process.
    • Light quality and intensity:
      • At LOW light intensities, as light INTENSITY INCREASES, RATE of photosynthesis INCREASES and is a LIMTIING factor.
      • At HIGH LIGHT intensities, rate of phototsynthesis PLATEAUS and light is no longer a limiting factor as it doesn't affect the rate.
    • CO2:
      • CO2 is a SUBSTRATE for photosynthesis and so increasing CO2 conc INCREASES RATE of photosynthesis.
      • At some point the rate of photosynthesis will PLATEAU.
    • Temperature:
      • INCREASING temperature INCREASES RATE of photosynthesis up to an OPTIMUM. At too HIGH a temperature, enzymes may DENATURE and rate will PLATEAU.
    • LIGHT has 3 main effects: OPENS STOMATA so CO2 can enter leaves. Trapped by CHLOROPHYLL where it EXCITES electrons. SPLITS WATER molecules to produce PROTONS.
    • Light INDEPENEDENT stage is ENZYME CONTROLLED whilst the light DEPENDENT stage is NOT.
      • When light is NOT limiting it is TEMPERATURE DEPENDENT and more likely to be enzyme controlled DEPENDENT
        • Increase in TEMP and decreasing rate shows ENZYME controlled.
          • When limited by light, it is temperature INSENSITIVE and NOT enzyme controlled.


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes and structure resources »