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Bioenergetics Lecture 5 summary

Explore similarities and differences between cellular respiration and photosynthesis, focusing on electron transport chain, ATP synthesis using H+ gradient, and energy transfer in photosystems. Learn about chlorophyll, ATP synthase, and the role of NADH and NADPH in these processes.

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Bioenergetics Lecture 5 summary

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  1. Bioenergetics Lecture 5 summary • Susan.Kaminskyj@usask.ca • Last time –integrating catabolic metabolism, review catabolism • This time • similarities and differences between cellular respiration and photosynthesis • chlorophyll, photosystems II and I (in that order) • But first….!

  2. F1 in matrix Fo in inner membrane Electron transport chain pumps H+, making a gradient ATP synthase uses the H+ gradient to generate ATP Higher H+ concentration = lower pH Intermembrane space Potential energy of ‘falling’ H+ used to generate ATP Potential energy of falling water used to grind grain Lower H+ concentration = higher pH Mitochondrial matrix

  3. ATP synthase uses the H+ gradient to generate ATP

  4. Cellular Respiration

  5. A series of redox reactions …. RESPIRATION PHOTOSYNTHESIS PHOTOSYNTHESIS RESPIRATION

  6. Mitochondria All aerobic eukaryotes Oxidation of CHO to CO2 Generation of NADH and FADH2  ATP synthesis Chloroplasts Plants, algae Energy harvest from sunlight Generation of NADPH  Reduction of CO2 to CHO Respiration vs photosynthesis CHO = carbohydrate P photosynthesis Note NADH (respiration) vs NADPH (photosynthesis)

  7. Photosynthesis is an endothermic redox process Sunlight Energy source? Useful byproducts? Glucose and O2

  8. Red and Blue light are absorbed from the incident (white) light, leaving Green to be reflected or transmitted

  9. Photosynthetic Active spectrum Photosynthesis produces oxygen Are all wavelengths photosynthetically active? Spirogyra

  10. First, light energy must be captured Illuminated chlorophyll fluoresces (gives off light) if captured light energy is not transferred to another acceptor

  11. Capture is not enough! In a leaf, the reaction centre transfers the captured energy to a relatively stable intermediate chemical Isolated chlorophyll fluoresces if newly captured energy is not transferred

  12. The reaction centre is the heart of the photosystem Energy transfer between pigment molecules to a special central pair of chlorophylls(reaction centre) and thence to the primary electron acceptors

  13. Two parts to the light reaction

  14. Chemiosmosis can make ATP

  15. Two parts to the light reaction phaeophytin ferredoxin

  16. Source and fate of carbon and oxygen in carbohydrates formed by photosynthesis

  17. Photosystem II makes ATP

  18. Photosystem I makes NADPH

  19. NADH vs NADPH • NADH  catabolism • NADPH  anabolism (P  photosynthesis) • For each, the reduced form stores ~ 3 times more energy than ATP

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