- Quiz: To check that you have obtained the objectives.
- Other related activities: For which you can investigate.
Photosynthesis Review
Please answer the following questions on a separate piece of paper. (Answers are available at the end of the quiz for you to compare. No cheating.)
- What is the function of P700 and P680?
- How does the light reactions begin (what is oxidized)?
- What is the main purpose of the light reactions?
- What is the final acceptor of the electrons in the light reactions?
- What is the main purpose of the dark or light independent reactions?
- How many times does the Calvin Cycle need to go around to create 1 PGAL for the formation of glucose? How many times must it go around to create a complete glucose molecule?
- Where is the glucose molecule produced?
- How is Oxygen produced and where does it go?
- Why is it proper to say that all living things are dependent on solar energy? (Mader, 1990; Thompson K. (class handout, April 2002))
Answers:
- P700 and P680 absorb light energy and funnel it to their reaction centers.
- Light reaction begins when H2O is been oxidized to 2 H+ and ½ O2.
- The main purpose of the light reactions is to photolyse water, release oxygen, and make 1 ATP.
- The final acceptor of the electrons in the light reactions is NADP+ to form NADPH.
- The main purpose of the dark reactions is to make simple sugar glucose.
- It takes 3 times for the formation of 1 PGAL as extra and 2 times of that to create a complete glucose molecule.
- Glucose is produced from the dark reactions in stroma.
- Oxygen is produced by photolysis in thylakoid space and goes to the ETC.
- It is proper to say that all living things are dependent on solar energy because photosynthesis requires sun light to start the reactions. Even pure carnivores themselves do not use solar energy, but the food they eat to stay alive ate plants. Without sunlight everything would shut down, we need oxygen, with is produced by plants fueling the entire planet with energy.
Other Activities
You can do a lab related to photosynthesis by visiting this web page:
The Effect of Decreased Light on Photosynthesis in Geranium Leaves The purpose of this lab is to discover if the amount of light affects photosynthesis in leaves. It's a very simple and easy to follow experiment for which everyone can do it at home. There will be some analysis for you to do at the end of the lab with answers provided. Give it a try. Also, the following are a few questions I would like you to answer. (Yes, you!)
- After how many days can you remove the shapes from the leaves?
- What will happen if sunlight is reduced, and what can you do about it?
- What will happen to the plants if there is no sunlight present?
- Can you think of any other ways of testing the amount of light affects photosynthesis in leaves?
- Suggest any possible improvement could be done for this experiment?
- Suggest a plausible hypothesis for this experiment.
- What is/are the independent variable(s) for this experiment (the controls)?
- What is/are the dependent variable(s) for this experiment?