Questions tagged [photosynthesis]

The process by which light energy is harnessed to assemble organic compounds (esp. glucose) from inorganic carbon dioxide.

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How many times did photosynthesis evolve?

Was it a 1 and done thing? Plants seem to have developed photosynthesis by the endosymbiosis of cyanobacteria. Is the latter the one time in Earth's history that the process independently came about? ...
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Would a plant survive in a 100% CO2 environment provided it has constant sunlight at all times?

I was looking up "do plants need oxygen" because I was confused and came upon this comment: "Basically, they need to breathe oxygen to survive, like we do. But they can also use the sun ...
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Can we achieve complete photosynthesis on a petri dish? Barriers and potential

If we were to place bacteriorhodopsin and ATP synthase in an acidified solution (for H+ ions) filled with phospholipids, ADP and inorganic phosphate, hopefully the bacteriorhodopsin and ATP synthase ...
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Can you explain why leaves of tree wilts during partial solar eclipse

It was a partial eclipse not even a complete eclispe even then leaves becames lazy . Why
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Are there any fluorescent proteins capable of transforming 500-600 nm light to 400-500 or 600-700 nm?

In order to improve photosynthesis, which doesn't use 500-600 nm light, I wonder if that light can be transformed into useful light? The idea is to transfect photosynthesis organisms with the gene for ...
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What part, roughly, of the carbon in a plant comes from the soil? As opposed to the atmosphere?

C4 plants contain a slightly higher percentage of carbon-13 than C3 plants. Is this because of carbon obtained from the soil or the atmosphere? I have read that plants using different chemical ...
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Can we produce sugar using chlorophyll dissolved in ethanol?

I can't find anything about this on the net. I read in my (high-school) textbook that if plants get sunlight, water and carbon dioxide, and the catalyst called chlorophyll, they can make sugar. I'm ...
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Is this question about limiting factors answerable?

This is from a Singapore-Cambridge GCE O-level Biology exam (a national exam for 16-year-olds). The exam board maintains that the question is "correct and accurate"—but isn't there a typo in ...
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How does the light-independent stage of photosynthesis get H+ ions?

From what I understand from my grade 11 biology: During the light-dependent stage of photosynthesis, water molecules split, producing hydrogen and oxygen atoms. The oxygen atoms are basically “waste ...
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How is Elysia chlorotica classified as an animal capable of photosynthesis?

Elysia chlorotica is a kind of sea slug. Technically, it's an animal. However, it undergoes a process called kleptoplasty, which is the absorption of chloroplasts from algal prey cells which are then ...
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How quickly are plants able to sense changes in light intensity?

Evidently due to the process of photosynthesis, plants are able to "sense" light (as demonstrated by the phototropic response). My question is, how quickly are plants able to perceive ...
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Is there such a thing as an autotroph that doesn't use photosynthesis?

I've heard of photoautotrophs, which are just autotrophs that use photosynthesis. What I'm wondering is if there's any other way for an organism to make its own food that doesn't involve it using ...
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Phytomass and photosynthesis

I have been introduced to the term "phytomass" and I was wondering if phytomass can be both photosynthetic and non-photosynthetic?
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Difference between the number of ps I and ps II complexes in cyanobacteria and plants

the number of photosystem I complexes are more than the number of photosystem II complexes in cyanobacteria, while this is opposite in plants. why? Is this related to the type of respiration?
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Respiration and Photosynthesis of Plant [duplicate]

With the respiration and photosynthesis relationship we know that the products of one of the processes are the reactants of the other. Why do plants still need a constant supply of oxygen, or carbon ...
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Is this the equation for photosynthesis carbon dioxide + water —- glucose +oxygen + water

Is water both a product and a reactant is photosynthesis and why?? I know that in the light dependent stage light energy is used to split water(photolysis) into oxygen and protons and electrons In ...
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Is there any study to find the plant with the absolute minimum light need?

Is there any study to find plants with absolute minimum light need? Consider a bathroom without windows that you have occasional artificial light (e.g. white LED light). Another question is there ...
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Do plants take in the same amount of CO2 as they release?

There are many claims in the media that trees remove more carbon dioxide form the atmosphere than they release back into the atmosphere. By what chemical pathway can this occur? The law that matter is ...
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Do plant cells recycle carbon dioxide from their respiration during photosynthesis? [duplicate]

It seems one of my colleague's biology textbook claims that plant cells, with presence of light, feed back 100% of carbon dioxide molecules from their respiration into photosynthesis. Can you say that ...
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Why do quaking aspens quake?

I've just finished reading The Hidden Lives of Trees by Peter Wohlleben, which I thoroughly enjoyed. According to the author, the advantage of shaking the leaves is that both sides of the leaf are ...
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Does photosynthesis begin instantly when a plant is exposed to light?

I'm curious to know if the process of photosynthesis has a "ramp-up" time to become useful to a plant, or if it begins instantaneously when the plant is exposed to light after a period of darkness. ...
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Nitrogen deficiency and chloroplast function

Q. The formation of which of the following in the chloroplast is affected by a deficiency in nitrogen? (a) Glyceraldehyde 3-phosphate (b) Starch (c) Enzymes (d) Carbohydrates My thoughts: Nitrogen ...
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Could Cyanobacteria farms help dilute pollutants in the atmosphere

If I understand correctly, roughly ~2.8 billion years ago cyanobacteria started pumping large amounts of oxygen into the atmosphere. Using modern industrial processes could this be emulated by ...
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Emerson's 2nd effect/ Emerson's enhancement effect and evidence of existence of 2 photosystems

(https://i.stack.imgur.com/Qbai6.jpg) https://en.m.wikipedia.org/wiki/Emerson_effect I can't understand why is there a need of 2 photosystems (2 interconnected pigment systems) to explain Emerson's ...
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Do plants refix some of the carbon dioxide in the Calvin cycle that they produce through cellular respiration?

Plants do cellular respiration and release CO2 into the air, but does the plant also use some of this CO2 to do the Calvin cycle? Or does all the CO2 required for the Calvin cycle come in through the ...
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Photolysis in the Light Reactions of Photosynthesis [duplicate]

I'm a bit confused concerning photolysis. During the light reactions, photons are used to excite the chlorophyll molecules so they are passed to the primary electron acceptor. The electrons initially ...
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Why does atrazine kill photosynthetic bacteria and not nonphotosynthetic bacteria?

Atrazine was found to bind to Qb, which is involved in electron transport to create ATP in photosynthetic bacteria. Why does this herbicide kill photosynthetic bacteria, while having little to no ...
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Plant respiration produces carbon dioxide, so why are plants regarded as decreasing its atmospheric concentration?

In the absence of sunlight, plants give out the greenhouse gas, carbon dioxide. So why is it said that plants increase the concentration of atmospheric oxygen? Do they not increase the concentration ...
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Effect of light intensity on the frequency of stomata

According to this article, the frequency of stomata increases with an increase in the intensity of light. What I inferred from this is, since the rate of photosynthesis increases at higher light ...
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267 views

How is C4 pathway more water efficient than C3 pathway in photosynthesis?

In the C3 pathway: 1 H2O molecule is required for the fixation of 1 CO2 molecule. In the C4 pathway: The only H2O molecule used is in the calvin cycle, so 1 H2O molecule required for fixation of 1 ...
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Photosynthesis production of oxygen [closed]

If you are to increase the intensity of light indefinitely, would you expect the production of oxygen to continue to increase?
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Photosynthesis immature fruits [duplicate]

Do immature fruits perform photosynthesis? Yes they have chlorophyll bodies. But do they have stomata through which they can absorb carbondioxide like the green leaves? Sincerely Ulrik
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Why have plants evolved to photosynthesize glucose instead of another molecular compound?

I think this question can be broken down into two sub-questions: Why do plants produce $C_6H_{12}O_6$ as opposed to another molecule following the formula of $C_nH_{2n}O_n$? Why not $C_8H_{16}O_8$, $...
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Chorophyll and photosynthesis in plants with coloured leaves

Do plants that have only coloured leaves (e.g. ‘ornamental’ plants) contain chlorophyll and perform photosynthesis? If they don’t, how do they obtain energy and metabolic intermediates?
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How many electrons does the b6-f complex need to pump one proton into the thylakoid lumen?

In photosynthesis, photons are used through photolysis to split water molecules and retrieve their hydrogen ions and electrons in the water-splitting complex. For each four photons, two water ...
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what is the integral of PAR radiation over total solar radiation

This paper say 48%: What is the maximum efficiency with which photosynthesis can convert solar energy into biomass? -Zhu 2008 Also why does Zhu use 740 nm at high end of PAR wavelength! My ...
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Which complexes physically pump protons in photosynthesis?

The cytochrome b6f complex is often drawn as pumping protons, but then someone told me that actually there is no pumping, rather the Q cycle. According to this view, what actually moves the protons ...
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How does the emerson effect produce a higher rate of photosynthesis?

Can anyone explain how the emerson effect works to increase the rate of photosynthesis, and as the original studies were done over 50 years ago, how much research is still done into this area? Or is ...
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Is coral photosynthesis dependant on the wavelength or frequency of light?

When buying a light fixture for a marine fish tank, it is often sold with some technical data reguarding the spectral output of the light, with a peak in the blue region of visible light, somewhere ...
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Why “Having chlorophyll without photosynthesis is actually very dangerous” and “like living with a bomb”?

The Phys.org article Scientists discover first organism with chlorophyll genes that doesn't photosynthesize says "For the first time scientists have found an organism that can produce ...
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Photosynthesis: Can light directly excite the reaction center instead of going through the antenna complex?

The reaction centers that I am interested in are P680(photosystem II) and P700 (photosystem I) Here is what I think: If pigments such as chlorophyll a and b capture light in the antenna complex, and ...
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Fuel from photosynthesis

I was reading how plants make use of sunlight, CO2 and some other stuff to make energy. So why can't we create artificially engineered bio solar panels which will take sunlight, C02, water and other ...
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Winter is getting shorter and warmer. Does this mean deciduous trees can photosynthesise for longer and thus absorb more carbon dioxide?

As springtime is starting earlier this year, I wondered if that would mean deciduous trees had more time to photosynthesise and, therefore, they could absorb more CO2 or have longer periods to grow, ...
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Calculation of Respiration Fluxes in Terrestrial Ecosystems Based on Total Respiration (RT)

Overview Researchers have been studying a temperate grassland ecosystem with the view to understand it's current status with regard to carbon inputs and outputs and to identify whether the grassland ...
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What does the difference between GPP - NPP represent?

Overview Researchers have been studying a temperate grassland ecosystem with the view to understand it's current status with regard to carbon inputs and outputs and to identify whether the grassland ...
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How much energy takes C4 photosyntesis to make glucose?

Wikipedia has a kind of contradiction that I would like to understand: According to this link The C3 pathway requires 18 ATP for the synthesis of one molecule of glucose while the C4 pathway ...
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Why is photosynthesis described as a “physico-chemical” process? [closed]

In my textbook it is given that photosynthesis is a physico-chemical process. How can it be a physical process?
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In plant photosynthesis, in the light dependent reactions, why is 3 ATP produced per 2 H2O?

I've been looking at the light-dependent reactions on Wikipedia and Khan Academy. This is the net reaction: $$2H_2O + 2NADP^+ + 3ADP + 3P_i \to O_2 + 2NADPH + 3ATP$$ So for every $2H_2O$ I expect $...
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What is the evolutionary relationship between heme, chlorophyll and other tetrapyrroles?

As a non-biologist, I have searched the Internet and found dozens of papers discussing the similarity between the structures of heme and chlorophyll molecules, but I could not find any discussion of ...
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What does the spectrum of Chlorophyll fluorescence look like?

I've just posted the question Which spacecraft can see plants "glow" during photosynthesis during the day, and what wavelength does it use? in a different SE site. I can't remember the details of ...

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