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47 votes

Does any organism use both photosynthesis and respiration?

tl;dr: Yes, all plants breathe.— I'm not sure whether I understand the question correctly; because all plants use respiration! Some of the organic high-energy substances produced by ...
Peter - Reinstate Monica's user avatar
45 votes
Accepted

Why "Having chlorophyll without photosynthesis is actually very dangerous" and "like living with a bomb"?

Chlorophyll absorbs photons (light). The energy in the photon extracts an electron from a molecule of water. Electron transfer creates intermediate superoxide and hydroxyl radicals from the oxygen and ...
Alex Reynolds's user avatar
41 votes
Accepted

Do photosynthesis and respiration violate the law of conservation of energy?

With slight adjustments to the scientific wording, what the poster states is in effect: “…to produce one molecule of glucose in photosynthesis, 18 ATP molecules are used up hydrolysed” and “…...
David's user avatar
  • 26k
28 votes
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Can plants suffer from CO2 poisoning?

Short answer It has been shown that plants may already suffer from doubling the atmospheric CO2 concentration from 340 to 610 ppm, something that might happen during the next hundred years or so based ...
AliceD's user avatar
  • 52.5k
20 votes

Why do plants have green leaves and not red?

I know this question was asked and answered a number of years ago (with many great answers), but I couldn't help but notice that no one had approached this from an evolutionary perspective (like the ...
theforestecologist's user avatar
20 votes
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Is agriculture really a net contributor of greenhouse gases?

The issue is that it is not always a cycle, when you drain wetlands or burn forests to make more farmland that's not a cycle that is permanent change. A change that can continue having effects for ...
John's user avatar
  • 14.7k
18 votes

Can plants suffer from CO2 poisoning?

It depends upon the plant species. As explained in Algae thrive under Pure CO2 Nature 227, pages 744–745 (15 August 1970): Cyanidium caldarium (an algae found in Yellowstone National Park) ...
DavePhD's user avatar
  • 756
16 votes

Chorophyll and photosynthesis in plants with coloured leaves

Most of ornamental (often variegated ) plants do performs photosynthesis. They do have chlorophyll even if their color is not green. They have non-green color due to various different pigments. These ...
Dexter's user avatar
  • 2,396
15 votes
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Does any organism use both photosynthesis and respiration?

Besides the unicellular organisms cited by other answers (and the fact that plants actually do respiration), there are some animals who are able to get, although indirectly, energy from photosynthesis ...
Afrog - TRUMP2024's user avatar
15 votes
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Why aren't leaves black?

Evolutionary answer: I like to go one step before green plants and consider the humble alga. Algae were historically classified as green, red, and brown, based on the wavelengths that their ...
aeffenberger's user avatar
15 votes

Why does photosynthesis specifically produce glucose?

Glucose is such a ubiquitous energy storage molecule, that we show the simple photosynthetic chemical equation to include the capture of six CO2 molecules to create one glucose molecule. However, the ...
Darlingtonia's user avatar
  • 2,589
14 votes
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Can plants produce oxygen at night (without light)?

Short Answer: Any plant can produce oxygen at night, but plants cannot produce oxygen without light. Longer Answer: It all comes down to spontaneity of a reaction i.e. whether a reaction can occur ...
another 'Homo sapien''s user avatar
13 votes

Are two colors (red + blue) necessary for LED grow lights, or would either color be sufficient?

tl;dr: Sort of? Logically, either red or blue light should be sufficient. Chlorophyll a and chlorophyll b preferentially activate different photosystems, and both photosystems are required in green ...
Resonating's user avatar
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12 votes
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Is it considered feasible to genetically improve plants for better Carbon dioxide breakdown?

I'm not sure from your question if you're clear on the relationship between carbon fixation and 'energy', so just to be clear: carbon fixation in photosynthesis is the process of capturing CO2 and ...
arboviral's user avatar
  • 3,354
11 votes

Why is chlorophyll green? Isn't there a more energetically favorable color?

The reason that chlorophyll is green is because it absorbs other colors of light such as red and blue, so in a way the green light is reflected out since the pigment does not absorb it. Because life ...
Ebbinghaus's user avatar
  • 2,603
11 votes

What part, roughly, of the carbon in a plant comes from the soil? As opposed to the atmosphere?

Only a small fraction of plant carbon is soil-derived: e.g. from Majlesi et al 2019: although the majority of plant C was obtained from atmosphere by photosynthesis, a significant portion (up to 3–5%)...
Ben Bolker's user avatar
  • 5,364
10 votes

Why does the oxygen produced in the photosynthesis come from water and not carbon dioxide?

It’s not about the oxygen! This question indicates two misplaced concerns. One is with oxygen. I imagine that this is because of its importance to us as animals; however as far as photosynthesis is ...
David's user avatar
  • 26k
9 votes
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The colour of aquatic plants found deep under oceans

You're right that certain wavelengths of light are more capable of penetrating deeper depths of water. However, it turns out, blue light typically travels to deeper depths than all other visible ...
theforestecologist's user avatar
8 votes

Why are C4 plants mainly tropical plants?

This is not my field, so the following is based solely on a brief reading of Internet sources. The Wikipedia entry on C4 carbon fixation states: When grown in the same environment, at 30°C, C3 ...
David's user avatar
  • 26k
8 votes

Do fish depend on plants for survival?

Yes, photosynthesis provides nearly all of the ocean's biomass and energy. The best is to study oceanic food chains and webs. It looks like there aren't enough plants in the ocean because they don't ...
bandybabboon's user avatar
  • 10.4k
7 votes

What determines the efficiency of electron production in photosynthetic bacteria?

You may or may not consider this an actual answer to your entire question, but it's interesting nonetheless. A physicist friend of mine did some work recently modelling the quantum dynamics of ...
Joe Healey's user avatar
  • 1,301
7 votes
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Violation of the law of energy conservation between photosynthesis and respiration?

The Fallacies in the argument The question contains two main fallacies (some would say sleights of hand) in the energetic comparison of glucose synthesis from CO2 in the Calvin cycle and glucose ...
David's user avatar
  • 26k
7 votes

Is it considered feasible to genetically improve plants for better Carbon dioxide breakdown?

Many if not most plants undergo less photosynthesis than they possibly could. This is because water availability is often their major limiting factor. Plants have to keep the tissue they respire ...
John's user avatar
  • 14.7k
7 votes
Accepted

Do fish depend on plants for survival?

Short answer All marine life needs energy to survive and reproduce. "Heterotrophic" organisms get their energy from eating other organisms and digesting the molecules of their tissues for ...
theforestecologist's user avatar
6 votes
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Quinone A, Quinone B, Ubiquinone, Plastoquinone: whats the difference?

Difference between Ubiquinone (UQ) and Plastoquinone (PQ) Structural Difference: Structurally, UQ and PQ are very similar. They only differ in a methyl group and 2 substituents on the benzoquinone ...
another 'Homo sapien''s user avatar
6 votes

How much oxygen does a plant use up at night?

Roughly, half of the CO2 assimilated annually through photosynthesis is released back to the atmosphere by plant respiration (Gifford, 1994; Amthor, 1995). Source: https://academic.oup.com/aob/...
aesthete's user avatar
  • 351
6 votes
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Do fallen leaves produce oxygen?

Short answer It all depends on the time window you are talking about. After having been detached from the mother plant, a leaf will typically keep on photosynthesizing for a few hours or so. ...
AliceD's user avatar
  • 52.5k
6 votes
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How is C4 pathway more water efficient than C3 pathway in photosynthesis?

Actually, water is used in the light-dependent portion of photosynthesis, not the Calvin cycle. The added water efficiency doesn't actually relate to water's involvement in chemical processes of ...
theforestecologist's user avatar

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