Wikipedia:Reference desk/Archives/Science/2020 June 5

= June 5 =

Oxygen in photosynthesis
In the 3rd sentence of the photosynthesis article, it states that: "In most cases, oxygen is also released as a waste product." I was wondering, in a broad sense, what that means. In which cases does this not occur? My 9th grade daughter learning bio asked me this question and I didn't know what it could be. Thanks!  DRosenbach  ( Talk 00:09, 5 June 2020 (UTC)
 * Possibly referring to plants that use close their stomata in daytime and use CAM photosynthesis. Conditions might allow them to use all self-produced oxygen in respiration while releasing little. Rmhermen (talk) 01:02, 5 June 2020 (UTC)
 * High school bio teacher chiming in. Even with CAM, oxygen is still produced as a waste product, because the light reaction is where oxygen is produced as the product due to photolysis, while CAM only changes the particulars of the carbon fixation pathway. Rather, this statement is a reference to anoxygenic photosynthesis (photosynthesis that does not produce oxygen), which some bacteria are able to perform. The vast majority of organisms today, however, produce oxygen during photosynthesis.  bibliomaniac  1  5  01:16, 5 June 2020 (UTC)
 * Thanks to both of you!  DRosenbach  ( Talk 21:36, 5 June 2020 (UTC)
 * Yeah, bacteria are insanely varied and do all kinds of things other organisms don't. For instance they and the similar archaea are the only organisms that produce Vitamin B12; everything that needs it as a vitamin gets it directly or indirectly from them (except if it's synthetic, since we clever monkeys have figured out how to brew it ourselves). When you see a statement about biology that says something like "in most cases", the exceptions are most likely bacteria and/or archaea. --47.146.63.87 (talk) 04:30, 6 June 2020 (UTC)