3.4 Photosynthesis
The conversion process that transforms the energy of sunlight into chemical energy stored in sugars and other organic molecules is called photosynthesis. Photosynthesis nourishes almost the entire living world directly or indirectly.
To Think About:
How do organisms capture and store energy for use in biological processes? How are the light-dependent reactions involved in the capturing and transforming of energy? What are the products of the light-dependent reactions? How are the light-dependent reactions and Calvin cycle reactions related? What is chlorophyll’s role in boosting electron energy levels? How do photosystem I and II (PSI and PSII) work together to create a proton gradient which facilitates ATP synthesis? How are products of the light-dependent reactions used in the Calvin cycle?
Watch: AP Daily Video Part 1 - Photosynthesis
Answer the Following Questions:
- Photosynthesis is the biological process that _______________________
- How did photosynthesis change Earth’s early atmosphere?
- Pigments help transform ______________________ into ______________ energy.
- This chemical energy is then temporarily stored as _______________
- Light-dependent reactions also produce another energy storing molecule called ___
- What happens to the NADPH and ATP produced by the light-dependent reactions?
- What process produces the oxygen released in the light-dependent reactions?
- PAUSE the video at 3:48, choose the correct answer and JUSTIFY your choice.
Watch: AP Daily Video Part 2 - Photosynthesis
Answer the Following Questions:
- During photosynthesis, chlorophyll captures the energy from sunlight and coverts it into _____________________ electrons.
- These high energy electrons are used to make ___________ and _________________
- Where are photosystem I and II located?
- What is a photosystem?
- The hydrogen molecules from the _________________ of water are released into the ______________________________ and are used to create an ____________________________________ gradient.
- The electrons that were excited by the energy captured from sunlight pass through an ________________________________________
- What is the function of PSI and PSII?
- What is an electrochemical/proton gradient?
- What can this proton gradient be used for?
- What does the enzyme ATP Synthase do?
- Which three things does the Calvin cycle use to produce carbohydrates?
- Where do the ATP and NADPH used in the Calvin cycle come from?
- Where does the carbon dioxide used to make carbohydrates come from?
- Describe the results of the experiment presented in Table 1 in the question at the end of the video.
Supplementary Resources:
- Bozeman Science: Mr. Andersen’s “Photosynthesis” video
Virtual Cell Animation: Photosynthesis (Light Reactions)
Wiley’s Interactive Concepts in Biochemistry: Photosynthesis
NOVA—Illuminating Photosynthesis: Help the process of photosynthesis along in this game
McGraw Hill: The Electron Transport System and ATP Synthesis
