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

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Is there a reason why human eyesight and plants make use of the same wavelength of light?

The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the ...
41
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4answers
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Why do plants have green leaves and not red?

I know plants are green due to chlorophyll. Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light ...
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4answers
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Do trees really get a large share of their mass from the carbon in the air?

I remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain ...
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How will rising carbon dioxide levels in the troposphere affect photosynthetic producers?

Much discussion has been had about the affects of climate change on plantlife, but how will rising carbon dioxide concentrations affect the photosynthetic process itself? Since CO2 is a reagent in ...
13
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1answer
2k views

How does a plant grow before photosynthesis is possible?

During photosynthesis, a plant translates CO2, water and light into O2. I assume the carbon C is further used for the growing process. I wonder how the plant grows before the time where photosynthesis ...
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NADH vs. NADPH: Where is each one used and why that instead of the other?

I know NADH is used in cellular respiration and NADPH is used in photosynthesis. What difference does the phosphate group make that the same one isn't or can't be used for both? Is there a greater ...
11
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1answer
94 views

Does a theory exist for the formation of thylakoid structure?

I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to ...
9
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3answers
329 views

What vegetation would thrive in the Martian atmosphere?

Most plants require carbon dioxide for their photosynthesis, which Mars has in overabundance. Would atmosphere composition (let's ignore temperatures for the purpose of this question) of Mars allow ...
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1answer
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What's the effect of oxygen deficit on plants?

As I know all cells require oxygen. So my question is how efficiently can plants operate in no-oxygen atmosphere? Do all plants produce enough oxygen for themselves? Can they consume their own oxygen ...
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489 views

Do plant-animal cross races exist?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
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Does Sansevieria trifasciata really absorb Carbon Dioxide at night?

There's a claim that Sansevieria trifasciata (Mother-in-law’s Tongue) generates oxygen from carbon dioxide during the night. This seems surprising to me: that process requires energy; plants generate ...
8
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1answer
356 views

Can Bioluminescence drive photosynthesis?

I'm trying to construct an anaerobic kitchen-waste digester at home. The major output from the digester is methane - with a significant component of carbon dioxide. To scrub/reduce the CO2 I was ...
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381 views

How do white Caladiums perform enough photosynthesis to support their mass?

In some white caladiums, there is less than a square inch of green space spread over the whole leaf. How do these plants perform the photosynthesis necessary to support the large leaves, the roots, ...
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83 views

Exactly which amino acids are phosphorylated in higher plants during state transitions?

I know it is usually stated as the threonine residue near the N-terminus of either light harvesting complex (lhc) b1 or lhcb2, but if this is somehow lost, say in a mutant, is the system flexible ...
7
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1answer
204 views

Compare and contrast “Rubisco activity” and “assimilation rate” (is there a difference, and if so, what is it)?

I am confused about the variable "RuBisCO activity". How is it measured, and is it any different from the net assimilation rate? Based on some background reading (e.g. Kling, 2008; Lambers et al ...
6
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1answer
323 views

Photosynthetic Pigments vs. Chloroplasts

What is the difference between Photosynthetic Pigments and Chloroplasts? I know plants have both but Prokaryotes (Bacteria and Archeae) only have the former.
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1answer
502 views

Do immature fruits perform photosynthesis?

Most immature fruits are green: peppers, pine cones, plums, lots of them. I want to know if the green is from chlorophyll in the cells. Do the fruit cells perform photosynthesis? When you cover a ...
6
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1answer
288 views

Can I estimate leaf temperature from air temperature? What other information would be required?

Physiological measurements such as respiration rate and assimilation rate depend on temperature. Most papers report tissue temperature (e.g. leaf temperature for leaf measurements), although some ...
5
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1answer
328 views

Do all plants photosynthesize with equal efficiency?

Just what the title states. Given identical, necessary and favourable conditions (Probably nutrients, humidity, and light but what I mean is all necessary requirements are fulfilled) - Is ...
5
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1answer
184 views

What is the lowest intensity threshold of light for photosynthesis in any species?

Recently, I was reading the question "Photosynthesis - light intensity, particularly the answer, that states that different species require different intensity of light. My question is what is the ...
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162 views

How high is the energy yield of photovoltaics compared to photosynthesis?

I'm not an expert in plant physiology. I was wondering if, per square centimeter, leaves are converting more or less energy than photovoltaic systems. Can this be estimated? How?
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1answer
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Does the light color spectrum and frequency matter for photosynthesis?

Do plants grow differently when given sun light, wolfram lamp, fluorescent light, LED light, infrared, ultraviolet, x-ray, unfocused laser and stroboscope?
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1answer
84 views

Photosynthesis regulation

I read about the regulation of Calvin cycle by thioredoxin which activates key enzymes essentially by converting disulphide linkages on inactive enzymes into sulfhydryls. Another regulatory mechanism ...
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364 views

What types of light can't a plant photosynthesize in?

I have a plant on my desk, and it got me to wondering: Can my plant use the light from my monitors to photosynthesize? If so, what light (apart from green light, to a degree) can't plants use to ...
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2answers
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Is there an evolutionary reason for the 5 electron transport complexes in plants and animals?

The electron transport chains of both the light reactions of photosynthesis (in plants) and oxidative phosphorylation (in animals) both contain 5 complexes including ATP synthase, as shown below. ...
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Why does the oxygen produced in the photosynthesis come from water and not CO$_2$?

In the photosynthesis equation $$6*CO_2+6*H_2O+sunlight\rightarrow C_6H_{12}O_6+6*O_2$$ the only place where we have 6 molecules of $O_2$ is in the $6*CO_2$. Then it reacts with $H_2O$ to form ...
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1answer
963 views

Does photosynthesis require only direct sunlight

I have learned throughout my basic science classes in high school that in the process of photosynthesis, plants absorb sunlight & produce food. They use carbon dioxide & water vapour. My ...
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40 views

What is the PAR (photosynthetically active radiation) curve, numerically speaking?

I'm trying to do some rough figuring to calculating efficiencies of various light sources for growing plants. I'm hampered, however, by the lack of a curve to multiply by the spectrum of light ...
3
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2answers
115 views

Would a plant need light if the chemicals gained by photosynthesis were given through the roots?

If you took the chemicals a plant gains through photosynthesis and put it through the plants' roots or by tubes, would the plant need light? If not, how would it respond to the treatment?
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What type of photosynthesis is performed by phytoplankton?

I am not a biologist, but I know there exist three variants of photosynthesis, namely C3, C4 and CAM. I would like to know what type is used by the ocean's phytoplankton? It might also be that ...
2
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1answer
69 views

How many plants are needed to survive in an airtight chamber?

How large a garden do you need if you are to survive on them producing enough oxygen in a closed chamber? And which are the most effective plants?
2
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1answer
208 views

How does this diagram illustrate carbon cycling in lakes?

Could someone please explain the following process to me: This process refers to carbon cycling in lakes and is described in the context of $CO_2$ flux from lakes into the atmosphere. GPP is gross ...
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2answers
58 views

Why isn't phosphorus or nitrogen a limiting nutrient for animals?

Nitrogen and Phosphorus are usually the limiting nutrient for plants, especially for algae. Phosphorus is used for DNA, ATP and phospholipids, and Nitrogen is used for pretty much every protein a ...
2
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1answer
56 views

Is infrared photosynthesis possible?

The post-apocalyptic science fiction novel Dark Universe by Daniel F. Galouye has some plants living inside bunkers that use infrared light for photosynthesis. There are speculations that ...
2
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1answer
45 views

Is there a limit to acceptable brightness for plants?

Can overly bright artificial light harm plants? Is it possible to achieve a level of brightness so high that it does more harm than good to plants? If sunlight can be filtered of infrared light ...
2
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1answer
88 views

Where does all the carbon go?

I found it hard to get numbers on global primary production, but apparently it's somewhere around 50-60 $Gt / year$ for carbon content in the terrestrial production, and a similar figure for the ...
2
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1answer
75 views

Can plants survive indefinitely without external supply of gases at compensation point?

During photosynthesis, there is a point at which the light intensity is such that the rate of photosynthesis exactly matches the rate of respiration called the compensation point. What this means is ...
2
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1answer
87 views

Is Hypericum Perforatum (St. John's wort) a C3 or C4 plant?

I've been curious as to which photosynthetic cycle St. John's wort uses to synthesise glucose and more complex carbohydrates. I know it probably won't be the crassulacean acid metabolism (CAM) cycle ...
2
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1answer
140 views

Independence of Light independent reaction in photosynthesis?

Inspired by a question asked to me by a classmate, I have the following question about Light-independent (dark phase) reactions in photosynthesis:- Let us suppose an algae sample was exposed to ...
2
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1answer
106 views

Photosynthesis - Light Intensity

Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis?
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How can oxygen production during photosynthesis be measured?

I'm curious how people measure quantitatively photosynthetic rate in labs. I've seen many qualitative examples with direct observations of bubbles forming in water due to photosynthetic output of ...
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1answer
55 views

Photosynthesis: Splitting Water

The splitting of water is an endergonic (non-spontaneous) reaction, and thus would require energy (chemical work to be done) in order to happen. In Photosystem II, an enzyme catalyzes this splitting, ...
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2answers
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Clarification on Hatch and slack pathway

The following is a minor clarification that I want to make, since it is rarely addressed directly in most of the texts I have gone through. In $C_4$ pathway, the chloroplasts are dimorphic, that ...
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1answer
244 views

Question regarding Rate of Photosynthesis AP Biology Lab

We are doing a lab on the effects of light intensity/wavelength on the rate of photosynthesis in AP bio and we were asked to visit this website here: ...
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1answer
92 views

Electron transport in granal stacks

See paper for distribution of PS-I and PS-II within grana As explained in the above paper, the PS-I complex is primarily located within non-appressed thylakoid region and stroma lamella, while PS-II ...
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1answer
131 views

Cyanobacterial photosynthetic oxygen yield

I am somehow not convinced that biotic factors are solely responsible for creating 21% of atmosphere (around 40 million moles of oxygen). There may be additional issues here. Since cyanobacteria ...
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1answer
108 views

What part of the cactus photosynthesizes?

In general, plants photosynthesize through their leaves and, to a much lesser extent, through their stems. Cacti, however, have no visible leaves, but instead spines. In what part of the cactus does ...
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0answers
39 views

Can anyone find published data which refers to the effect of light intensity on the rate of photosynthesis of a plant?

For school I need to refer to published data which refers to the effect of varying light intensities on the volume of oxygen emitted by the plant as a product of photosynthesis.
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1answer
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Confusion regarding photosynthesis and respiration in plants

During 24 hours there is a time in i.e. twilight when plants neither give oxygen nor carbon dioxide why is it so? This also suggests that neither of the two vital processes i.e. respiration or ...
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1answer
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How is photosynthesis observed?

How is photosynthesis observed? Say I have plants A and B, and I want to find how fast they are able to turn carbon dioxide into oxygen. How would I experiment this? Say I have one plant A, which ...