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Clues beginning to emerge on asymtomatic SARS-CoV-2 infection
Back in November of 2020, during the first wave of the COVID-19 pandemic, I was teaching an in-person microbiology laboratory. One of my students had just been home to see his parents, and they all c…
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Could there maybe be better uses of genetics and probiotics?
Professor Meng Dong and his laboratory have created a probiotic that can metabolize alcohol quickly and maybe prevent some of the adverse effects of alcohol consumption. The scientists cloned a highl…
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ChatGPT is not the end of essays in education
The takeover of AI is upon us! AI can now take all our jobs, is the click-bait premise you hear from the news. While I cannot predict the future, I am dubious that AI will play such a dubious role in…
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Fighting infections with infections
Multi-drug-resistant bacterial infections are becoming more of an issue, with 1.2 million people dying of previously treatable bacterial infections. Scientists are frantically searching for new metho…
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A tale of two colleges
COVID-19 at the University of Wisconsin this fall has been pretty much a non-issue. While we are wearing masks, full in-person teaching is happening on campus. Bars, restaurants, and all other busine…
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Figure 9.10. Electron transport in Rhodobacter sphaeroides. Light is collected through the light-harvesting complexes and excites a special pair of BChl that sits near the periplasm. As this excites, the special pair relaxes and an electron is ejected, reducing the nearby bacteriopheophytin. From here the electron travels toward the cytoplasm where it eventually reduces quinone B near the cytoplasmic side of the membrane. The reduction of quinone B also consumes one proton from the cytoplasm. A second round of excitation of the special pair brings a second electron to quinone B that picks up another proton from the cytoplasm and diffuses away from the reaction center and into the quinone pool of the membrane. This reduced quinone then is oxidized at the cytochrome b/c1 complex in a similar fashion as to what is observed in oxidative phosphorylation. The reduction of quinone B and its oxidation at the cytochrome b/c1 complex results in the generation of a proton motive force. That is used to generate ATP using the ever-familiar ATP synthase we discussed earlier. The low energy electrons from the b/c1 complex are then donated to cytochrome c2, and finally end up reducing the Mg atom in the special pair to complete the cycle. This process is termed cyclic photophosphorylation because the electrons travel a close circuit. Contrast this with oxidative phosphorylation where the electrons are eventually donated to oxygen.