Investigating Photosynthesis Flashcards
What plant can be used to measure the effect of light intensity on the rate of photosynthesis?
Canadian Pondweed
What can we use to tell the rate of photosynthesis in the experiment?
The rate of oxygen production.
Should the gas syringe be full or empty to start with?
Empty
What may be added to the water and why?
Sodium hydrogencarbonate may be added to the water to make sure the plant has enough carbon dioxide. (Sodium hydrogencarbonate releases CO2 in solution).
What should you make sure about the position in which you place your white light?
That it is at a specific distance from the pondweed.
What will happen to the oxygen produced as photosynthesis occurs?
It will collect in the glass syringe allowing it to be accurately measured.
What do you change when you repeat the experiment?
The distance from the pondweed.
How do you calculate the rate of oxygen production at each distance?
volume produced / time taken
How can you control the other two factors of photosynthesis?
You can place the conical flask in a water bath to control the temperature and you can add a set volume of sodium hydrogencarbonate to a set volume of water to control the carbond dioxide concentration.
What should you always remember when modifying this experiment to test the effect of carbon dioxide concentration or temperature on photosynthesis?
To only change one variable at a time.
What other organism can you use to investigate photosynthesis?
Algal Balls. Small balls of jelly which contain algae.
How else could you measure the amount of oxygen produced? What is the problem with this method?
By counting the number of bubbles given off in a certain time. This is less accurate.
