Lect_12_notes - in mitochondria and NADPH for use in Calvin...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 12 Notes Bio 1A Professor Schlissel February 20, 2008 Photosynthesis: The Light and Dark Reactions 1. A comparison of the overall reactions of respiration and photosynthesis. Where does the energy come from? 2. Structure of the chloroplast and the thylakoid membranes. 3. Light reactions generate ATP and NADPH which are used to “fix” carbon in the form of CO 2 into sugars via the Calvin cycle. 4. The absorption of light by pigments. Chlorophyll, b-carotene. Absorption spectra. Resonance energy transfer (RET). 5. The photosystem—a set of antenna molecules to capture photons and to transfer energy from them to the reaction center. Two special chlorophylls in reaction center, bound to proteins, which transfer excited electron to primary electron acceptor. Also, serves as oxidizing agent to split water into O 2 and H + . 6. Photosystem I and Photosystem II. P700 and P680. Linked in non-cyclic electron flow (also called “Z-scheme”) to generate proton motive force (resulting in ATP synthesis as
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: in mitochondria) and NADPH for use in Calvin cycle. 7. Cyclic electron flow—photosystem I uses light energy to make ATP, but NOT NADPH. Unlinked from PS II. 8. Orientation of ATP synthase in chloroplasts as compared to mitochondria. 9. Carbon fixation by the Dark Reactions. Ribulose biphosphate carboxylase (“Rubisco”) is the key enzyme which adds CO 2 to RuBP and generates 2 molecules of 3-phosphoglycerate. Calvin cycle then uses ATP and NADPH to convert these into glyceraldehyde 3-phosphate which can be used to synthesize glucose. 10. Its more complicated than this. CO 2 is sometimes limiting so plants have to find additional ways to hold on to CO 2 while not losing too much water. 11. Photorespiration occurs when O 2 concentration is high. RuBisCO uses O 2 instead of CO 2 to generate 3-phosphoglycerate and glycolate. Glycolate metabolism releases CO 2 back to the environment in a reaction which uses ATP, reversing the effects of photosynthesis. Why would such a pathway exist?...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern