Talk:Photosynthesis

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Semi-protected edit request on 8 March 2022

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in the text there is a typo. Change the word "photosyntethic" to "photosynthetic" Mfmdec (talk) 16:06, 8 March 2022 (UTC)[reply]

Good catch, thanks.

Done BelowTheSun (T•C) 16:17, 8 March 2022 (UTC)[reply]

Equation not correct

We read in section "Light-independent reactions", calvin cycle: 3 CO2 + 9 ATP + 6 NADPH + 6 H+ → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+ + 3 H2O

But this is not correct, it should be:

3 CO2 + 9 ATP + 6 NADPH + 6 H+ + 5 H2O → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+

Not water is produced, rather needed for the hydrolysis of ATP->ADP. If you don't believe me, don't write ATP, but C10H16N5O13P3 and ADP is C10H15N5O10P2. --2A02:810D:1600:2FD0:7C48:3C9:B08C:7686 (talk) 12:50, 11 April 2022 (UTC)[reply]

oxygen "stores chemical energy"?

I find the following sentence in the lede less than helpful:

In most cases, oxygen is also released as a waste product that stores three times more chemical energy than the carbohydrates.

That sentence simply makes very little sense: chemical energy is released or stored through chemical reactions. There's no absolute way of saying that 6 O2 contains "three times more chemical energy" than glucose. All you can say is how much energy is required for the overall reaction producing those two products from CO2 and water. (The story is very different for nuclear reactions, E=mc² etc. etc.)

In fact, what the reference talks about is the bond energy of O2, that released by the reaction ${\ce {O + O -> O2}}$ of monatomic oxygen to O2. That bond energy is 498 kJ per mole of O2 produced. Great. The hypothetical reaction 6 C + 12 H + 6 O -> glucose releases, apparently, 9672 kJ per mole of glucose produced.

That doesn't mean that O₂ "contains more chemical energy" than glucose. It certainly doesn't mean that it "stores three times more chemical energy". For starters, 9672 isn't "3 times more" than 2988, it's 3.23 times as much. More importantly, again, this is the energy released by forming bonds.

Quite the reverse is true: if, hypothetically, we had an infinite supply of glucose and split it into its individual (non-bonded) atoms, the products of that reaction would store 3.23 times as much energy per mole of glucose as splitting 6 moles of oxygen into its monatomic form could store. (Which is a silly idea under standard conditions, because the monatomic oxygen would form molecules almost right away.)

So the numbers simply don't mean what the article claims they do; the "three times more" is incorrect; the reference doesn't mention any factor of 4 (or 3); the reference should be secondary for such an important statement (or at least it would be important if it made sense).

I'm removing the sentence. Feel free to revert and discuss, but as it is it's unsourced OR which misrepresents what I'm pretty sure the authors of the paper intended to say.

IpseCustos (talk) 20:35, 7 June 2022 (UTC)[reply]

Correcting the structure of pyruvate in the image "Overview of C4 carbon fixation"

Hello, I´m not an expert on this topic, but I happened to notice, that in the image "Overview of C4 carbon fixation" the structure of the pyruvate is (to my belief) wrong. It features a hydroxy group on C2, however there should be a carbonyl group https://de.wikipedia.org/wiki/Pyruvate. The Molecule that is shown should be lactic acid. Silizimon (talk) 12:33, 25 July 2022 (UTC)[reply]

Semi-protected edit request on 17 August 2022

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and thats why the sky is blue Hannah blood (talk) 12:12, 17 August 2022 (UTC)[reply]

Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. EnIRtpf09b^{chat with me}

As discussed in Diffuse_sky_radiation#Color, the explanation has nothing to do with photosynthesis, but rather that blue light is scattered more.^[1] Boghog (talk) 07:30, 18 August 2022 (UTC)[reply]

References

^ "Why Is the Sky Blue?". NASA. Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered more than the other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

photosynthesis

Without photosynthesis their would be no life.During photosynthesis plants take carbon dioxide (CO2) and water (H20) from the air and soil. (By:Fatima waseem) 69.112.151.30 (talk) 14:08, 19 August 2022 (UTC)[reply]

Photosynthesis and solar panels efficiencies

Plants usually convert light into chemical energy with a photosynthetic efficiency of 3–6%. By comparison, solar panels convert light into electric energy at an efficiency of approximately 6–20% for mass-produced panels, and above 40% in laboratory devices. The 6-20% is now 20-40% and the electric energy of the panels is virtually infinite temperature while recombining hydrocarbons and oxygen at most gives a couple of thousand Kelvins. For most modern uses this corresponds to another factor of 3 in desirability of the photovoltaic power. On the other side plants can build themselves, but also use some of the energy for themselves at least until they die. Apart for personal considerations a hard to make comparison. The most striking consideration is that the average american uses as much primary energy as what's produced by photosynthesis pro capite, no wonder we are in trouble. Oscar Blauman 10:49, 1 October 2022 (UTC) — Preceding unsigned comment added by Omblauman (talk • contribs)

Wiki Education assignment: Plant Ecology Winter 2023

This article was the subject of a Wiki Education Foundation-supported course assignment, between 16 January 2023 and 10 April 2023. Further details are available on the course page. Student editor(s): Epipremnum aureum (article contribs).

— Assignment last updated by Epipremnum aureum (talk) 02:21, 9 February 2023 (UTC)[reply]

Glucose and fructose

Lots of fruits are rich in glucose and fructose. I added the fact that these come from hexose phosphates (obviously), but I can't find any information on how. Can someone supply this? Is it done by the enzymes that phosphorylate glucose and fructose? If so, does producing them from the corresponding phosphates give an ATP as well? Eric Kvaalen (talk) 16:40, 3 April 2023 (UTC)[reply]

Semi-protected edit request on 22 October 2023

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add citation: https://www.google.nl/books/edition/Essentials_of_Biochemistry/yf3EDwAAQBAJ?hl=en&gbpv=1&dq=photosynthesis,+used+mostly+by+bacteria,+which+consume+carbon+dioxide+but+do+not+release+oxygen&pg=PA275&printsec=frontcover

"There are also many varieties of anoxygenic photosynthesis, used mostly by bacteria, which consume carbon dioxide but do not release oxygen.[citation needed]" Internetsleuth (talk) 09:59, 22 October 2023 (UTC)[reply]

@Internetsleuth: Thanks for the suggestion, but unfortunately that book looks to have copied the text from this article, so citing it would be a case of WP:CITOGENESIS. SmartSE (talk) 10:11, 22 October 2023 (UTC)[reply]

Semi-protected edit request on 11 November 2023

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just to update year of discovering that mass is added due to uptake of CO2 and water stuff(1804) WorldDiagram837 (talk) 15:51, 11 November 2023 (UTC)[reply]

Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. Cannolis (talk) 19:26, 11 November 2023 (UTC)[reply]

Typo in Text

Photosynthesis is misspelled in this paragraph:

Photosyntesis was first discovered in 1779 by Jan Ingenhousz; he showed that plants need light, not just air, soil, and water. Brewkey (talk) 02:57, 12 July 2024 (UTC)[reply]

Deep-water Photosynthesis

A study published 04 September 2024 in Nature Communication presents "measurements from the MOSAiC field campaign in the central Arctic Ocean that reveal the resumption of photosynthetic growth and algal biomass buildup under the ice pack at a daily average irradiance of not more than 0.04 ± 0.02 µmol photons m⁻²⋅s⁻¹ in late March. This is at least one order of magnitude lower than previous estimates (0.3–5 µmol photons m⁻²⋅s⁻¹) and near the theoretical minimum light requirement of photosynthesis (0.01 µmol photons m⁻²⋅s⁻¹)." The article uses interesting units of light intensity (moles of photons per area per second) that might be converted to more conventional units of irradiance e.g., W⋅m⁻², to compare the photosynthetic efficiency of these algae compared to other chromophores. This study was written up in an article in The Conversation https://theconversation.com/plants-can-grow-in-near-darkness-new-research-shows-here-are-three-promising-benefits-238469

Reference: Hoppe, C.J.M., Fuchs, N., Notz, D. et al. Photosynthetic light requirement near the theoretical minimum detected in Arctic microalgae. Nature Communication 15, 7385 (2024). https://doi.org/10.1038/s41467-024-51636-8 Jtonti (talk) 03:00, 16 September 2024 (UTC)[reply]

[1] "Why Is the Sky Blue?". NASA. Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered more than the other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

[1]