The rate of photosynthesis Flashcards
What effects the rate of photosynthesis?
Intensity of light
Volume of CO2
Temperature
Water (however a plant has other bigger problems if it doesn’t have enough water)
What’s the term for something that makes the rate of photosynthesis slower?
Limiting factor
What is the limiting factor at night?
Light
What is the limiting factor in winter?
often the temperature
What is the limiting factor when it is warm and bright enough?
Usually CO2
What experiment should you do to work out a plant’s ideal conditions for photosynthesis?
The bubble experiment
Eg. With pondweed, count the bubbles it produces (Oxygen) and test which light level (by moving the light) produces the most bubbles.
As the light level is raised, the rate of photosynthesis [ ] [ ] - but only up to a certain point! (It’s the with [ ] level)!
increases steadily
CO2
Why does the rate of photosynthesis become constant after a certain point when you increase the light level?
Something else becomes a limiting factor (Temp or CO2)
Describe a way you can control the level of CO2
Dissolve different amounts of sodium hydrogencarbonate in the water, which gives off CO2
Why is temperature usually the limiting factor?
The temp is usually too low, therefore the enzymes, needed for photosynthesis work more slowly
What happens when the temp gets too high?
The enzymes get damaged (denature), at around 45°C, and stop working which means photosynthesis stops
How could you keep something at a constant temp, in an experiment?
Use a water bath
The most common way to create the ideal [ ] for plants is to grow them in a [ ].
environment
greenhouse
How to greenhouses stop temp becoming a limiting factor?
They trap the sun’s heat so it is warm enough however, it can get too hot
What do you do if your greenhouse is too hot?
Use shades or ventilation
