2nd PPE Biology Higher Revision (H)

2nd PPE Revision- Biology Higher

PhotoSynthesis:

Equation:

Carbon Dioxide+ Water---> Glucose + Oxygen

6CO2          +  6H2O---> C6H1206+ 6O2

Limiting Factors:

1. Light Intensity

2. CO2

3. Temperature

How Plants Use Glucose:

1. Respiration- Convert into other Useful Substances

2. Cellulose Production- Make Cell Strong

3. Amino Acid Production- Combine with Nitrate Ions= Protein= Plant Growth

4. Storing as Starch- in Roots, Stem, Leaves for Photosynthesis when plant Can't e.g. Winter

5. Storing as Lipids (Oil & Fat) in Seed

Rate of Photosynthesis, Graphs & Limiting Factors:

   Here the Light Intensity Increases but then stays at a Constant Rate= NOT Limiting Factor anymore= Rate Cannot go Faster and CO2 or Temperature is.

 CO2 Increases at the Start so it was a Limiting Factor until the Line Stays at a Constant Rate= Rate Cannot go Faster + Another Factor is Limiting ( Light/ Temperature)

 Temperature is slightly different because this includes Enzymes. On this graph you can see that it Increases at the Start and reaches a Curve at the Top= Optimum Temperature for Photosynthetic Enzymes to Work; then Steadily Decrease due to Enzymes becoming Denatured about 45 C.

Look in Revision Guide Pgs- 51 to 52

Practical: How to Investigate the Rate of Photosynthesis using Pondweed + Light+ Gas Syringe+  x2 Rulers

Variables:

Independant (Change)

1. Distance of Light Source from Pondweed

Dependant (Measure)

1. Time- How long it takes for the Pondweed to Photosynthesise

2. Gas Bubbles (Oxygen)- Count

Control (Same)

1. Length of Pondweed

2. Same Pondweed…