Photosynthesis equation quiz 1 of 46 Boardworks Ltd

Photosynthesis equation quiz 1 of 46 © Boardworks Ltd 2007

National 5 Cell Biology Photosynthesis Limiting Factors

We are learning to: • State the limiting factors of photosynthesis • Describe how the rate of photosynthesis can be measured • Analyse graphs showing how limiting factors affect the rate of photosynthesis • Explain the impact of a limiting factor on photosynthesis and cell growth

What I'm looking for: • Three limiting factors of photosynthesis • Explanation of why each factor controls the rate of photosynthesis • Labelled graph showing how different factors affect rate of photosynthesis

Limiting Factors

What is the rate of photosynthesis? Photosynthesis is a chemical reaction and so has a rate. Like many reactions, photosynthesis requires enzymes. Is the rate of photosynthesis always the same? Which factors do you think affect the rate of photosynthesis? light carbon dioxide temperature How do these factors affect the rate of photosynthesis? 6 of 46 © Boardworks Ltd 2007

Investigating Limiting Factors – immobilised algae

1. Immobilising the algae • Add 2 cm 3 of sodium alginate into beaker • Add 2 cm 3 of algae culture • Stir well

1. Immobilising the algae • Collect the sodium alginate and algae mixture into a syringe • DROP mixture in 10 cm 3 of calcium chloride

1. Immobilising the algae • Filter off the calcium chloride • Collect the beads

2. Investigation light intensity • Separate the beads between 4 Mac. Cartney bottles • Add 5 ml of bicarbonate indicator • Place the lid on the bottle • Place at different distances from the lamp

3. Results • Bicarbonate indicator – Yellow indicates carbon dioxide – Purple indicates less carbon dioxide The further the distance the bottle is from the light source, the lower the light intensity and the less photosynthesis

Investigating photosynthesis 13 of 46 © Boardworks Ltd 2007

Investigation photosynthesis 14 of 46 © Boardworks Ltd 2007

Limiting factors – activity 15 of 46 © Boardworks Ltd 2007

What is the limiting factor?

What is the limiting factor?

What is a limiting factor? What is the ideal combination of factors for the maximum rate of photosynthesis? l enough light l enough carbon dioxide l ideal temperature (not too hot or cold). How does restricting one of these facts affect the rate? If one of the factors is restricted, the rate of photosynthesis will be below the maximum possible rate. The restricted factor controls how quickly photosynthesis occurs and so limits the rate. It is called the limiting factor. 18 of 46 © Boardworks Ltd 2007

Limiting factors in a greenhouse 19 of 46 © Boardworks Ltd 2007

I can: • State the limiting factors of photosynthesis • Describe how the rate of photosynthesis can be measured • Analyse graphs showing how limiting factors affect the rate of photosynthesis • Explain the impact of a limiting factor on photosynthesis and cell growth