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Teaching the Z-Scheme of electron transport in photosynthesis: a perspective

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Abstract

This paper deals with how Govindjee taught the Z-Scheme of electron transport in oxygenic photosynthesis at Ravenshaw University, Cuttack, Odisha, India, in 2014, in a unique and highly effective fashion—using students to act as molecules, representing the entire electron transport chain from water to nicotinamide adenine dinucleotide phosphate (NADP+). It culminated in a show by B.Sc. students in the garden of the Department of Botany, Ravenshaw University. The first author (PKM) personally acted as Ferredoxin NADP Reductase (FNR) catalyzing the reduction of NADP+ to NADPH, taking electrons from reduced ferredoxin at the end of Photosystem I. On the other hand, the Q-cycle was played by M.Sc. students, who acted as molecules running this ingenious cycle that produces extra protons. An interesting event was when a student, acting as a herbicide, who was dressed like a devil (fierce looking, in black clothes with a sword; “Yamaraj: The God of Death”, as he called himself), stopped all reactions by throwing out QB, the second plastoquinone molecule of Photosystem II, and that too aggressively, taking its position instead. The second author was the major organizer of the Z-scheme show. We provide here a basic background on the process, a bit on Govindjee’s teaching, and some selected pictures from the drama played in March, 2014 at Ravenshaw University. Here, we also recognize the teacher Govindjee for his ingenious and fun-filled teaching methods that touched the hearts and the souls of the students as well as the teachers of Ravenshaw University. He was rated as one of the most-admired teachers of plant biology at our university.

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Acknowledgments

We thank the Vice Chancellor Professor Baishnab Charan Tripathy for inviting Professor Govindjee to Ravenshaw University. We are thankful to Dr. Soumendra Kumar Naik, Dr. Padan Kumar Jena, all the faculty members of the Department of Botany, and all the B.Sc. & M.Sc. students for their cooperation. Special mention is made of Ankita Prusty and Prakash Prasad for their hard and friendly work and assistance during Govindjee’s stay. We are highly thankful to Tina (Trinath Barik) for the photographs and the video. We thank Sripadma Debata for her help in the demonstration of fluorescence to High School students attending the INSPIRE program; Sasmita (one name only) for showing students how to access electronic journals, available through Ravenshaw University library, and Y. Chandrakala (for help in several demonstations), and many others of the department, who made the stay of Govindjee at Ravenshaw comfortable and, more importantly, encouraged us to prepare this news report for the purpose of spreading education around the world. We are grateful to the following for their valuable comments that led to an improvement of this manuscript: Robert Blankenship, Julian Eaton-Rye, and Baishnab Charan Tripathy. Finally, we thank Govindjee for providing us a great deal of information that is included here as well as for reading this text and approving its publication in its present form.

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Authors and Affiliations

  1. Department of Botany, Ravenshaw University, Cuttack, 753003, Odisha, India

    Pradipta Kumar Mohapatra & Nihar Ranjan Singh

Authors
  1. Pradipta Kumar Mohapatra
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  2. Nihar Ranjan Singh
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Correspondence to Pradipta Kumar Mohapatra.

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Supplementary material 1 (PDF 1888 kb)

Appendices

Appendix 1

Demonstration of Chlorophyll a fluorescence

The exciting power of chlorophyll a fluorescence as a signature of photosynthesis was shown by Govindjee to all the higher secondary school level students in a special lecture he was invited to give at Ravenshaw University; this lecture was coupled with practical demonstration, which was attended by ~160 students, and many teachers, from different colleges of the state of Odisha. Without taking the help of any sophisticated equipment Govindjee demonstrated how the tiny (2–10 % of the absorbed light; see e.g., Trissl et al. 1993) chlorophyll a fluorescence can be seen through naked eye in a comparatively dark room. Using leaves, he showed that the red chlorophyll a fluorescence, in a leaf, was not visible at all; and that from extracted chlorophyll was barely visible in the lecture hall. When he excited the leaf with a UV lamp, however, it was brilliant red in extracted chlorophyll (see a photograph of chlorophyll fluorescence in Govindjee and Govindjee 1974). What was interesting for students was to see that as leaves were infused with DCMU, they could observe red fluorescence, from the surface of the leaves with their eyes. This was so because when electron flow was inhibited beyond QA, the first plastoquinone acceptor of PS II, chlorophyll a fluorescence was high since the reaction center of PS II was “closed”, and photochemistry was not possible leading to lowered competition with fluorescence. He also explained how chlorophyll a fluorescence has proved to be an open window of photosynthesis research in general and light reactions in particular due to its intricate connection with a series of interactive and interdependent processes that take place during light-induced electron transport (see chapters in Govindjee et al. 1986; Papageorgiou and Govindjee 2004). While lecturing on fluorescence Govindjee did not forget to mention about the origin of the concept of fluorescence and showed the “celestial blue” light under UV light from tonic water. Like a young man he searched around the city of Cuttack, with a motorbike (driven by Prakash Prasad, in his class), to procure tonic water for his lecture-demonstration class, which shows his passion and commitment for the subject and deserves appreciation. (Fig. 4).

Appendix 2

  1. (A)

    Some useful web sites are:

    1. (1)

      Photosynthesis Web resources by L.Orr and Govindjee is at: http://www.life.illinois.edu/govindjee/Electronic%20Publications/2006/2006_gov_krogmann.pdf

    2. (2)

      The Photosynthetic Process by J. Whitmarsh and Govindjee is at: http://www.life.illinois.edu/govindjee/paper/gov.html

    3. (3)

      Milestones in Photosynthesis Research by Govindjee is at: http://www.life.illinois.edu/govindjee/papers/milestones.html

    4. (4)

      Photosynthesis and Time is at: http://www.life.illinois.edu/cgi-bin/gov/gov.cgi

    5. (5)

      Introduction of Photosynthesis and its Applications by Wim Vermaas is at http://photoscience.la.asu.edu/photosyn/education/photointro.html

    6. (6)

      TimeLine of Photosynthesis by Govindjee and D. Krogmann is at: http://www.life.illinois.edu/govindjee/Electronic%20Publications/2006/2006_gov_krogmann.pdf

    7. (7)

      Govindjee’s book collections are at: http://www.life.illinois.edu/govindjee/g/Books.html

    8. (8)

      Publications of Govindjee from 1994-2014 can be found at (there are some educational reviews there) http://www.life.illinois.edu/govindjee/recent_papers.html

  2. (B)

    Other web sites students may want to explore include:

    http://www.hansatech instruments.com/forum/uploads/david_walker/down %20hill.pdf

    http://en.wikipedia.org/wiki/Photosynthesis

    http://en.wikipedia.org/wiki/Light-dependent_reactions

    http://chemwiki.ucdavis.edu/Biological_Chemistry/Photosynthesis/Photosynthesis_overview/The_Light_Reactions

    http://icewater.cms.udel.edu/mast634/lectures/12-photosynthesis.pdf

  1. (C)

    You-Tube presentations can be searched through “Google”; two are mentioned below:

    1. (1)

      An interview with Govindjee is at: https://www.youtube.com/watch?v=cOzuL0vxEi0

    2. (2)

      An interview with Pierre Joliot is at: https://www.youtube.com/watch?v=Tz4uIveE2hI

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Mohapatra, P.K., Singh, N.R. Teaching the Z-Scheme of electron transport in photosynthesis: a perspective. Photosynth Res 123, 105–114 (2015). https://doi.org/10.1007/s11120-014-0034-4

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