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

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How long can a plant generate oxygen from its own carbon dioxide, produced during nighttime?

I recently bought one of these miracle fruit plants (Synsepalum dulcificum). Since they are of tropic origin, they need higher humidity and temperature as we have it here in Austria. So I decided to ...
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66 views

How to calculate PAR and aPAR from reflected + incoming radiance

i have measured the reflected radiance of a plant and the incoming radiance with a point spectrometer from 300 to 700 nm in 1nm increments. How can i calculate photosynthetically active radiation ...
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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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60 views

The definition of leaf area index

In many textbooks, leaf area index (LAI) is defined as the total leaf area per unit ground area. I want to know LAI is defined only by leaves that are directly above the ground (e.g., perpendicular ...
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276 views

Organisms using thermal energy as their sole energy source

After seeing this question I remembered that in secondary school we watched a documentary stating something along the lines of "all organisms derive their energy directly or indirectly from the sun. ...
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72 views

How does a garlic clove thrive inside a closed refrigerator?

A garlic clove has been growing very well inside a closed refrigerator. It has developed beautiful green stalks, which I think are the equivalent of leafs. Since they are green, I assume they ...
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3k views

When is Water Produced During Photosynthesis?

The formula for photosynthesis is: $$6CO_2+12H_2O \rightarrow C_6H_{12}O_6+6O_2+6H_2O$$ I can count the carbons, the waters on the reactant side, the oxygens, and the glucose, but I cannot seem to ...
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23 views

What is the use of crystallized Photosystems from cyanobacteria?

I read a lot of articles about techniques for the crystallization of Photosystem I and II from cyanobacteria. My question is what is the reason for that and what can you do with Photosystem crystals?
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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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24 views

Photosynthetic efficiency and light harvesting efficiency

Is there some sort of measure of the light harvesting efficiency (possibly like transfer time) that is directly related to the photosynthetic efficiency in some sort of equation? Also, how important ...
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90 views

Why is there a seeming dichotomy between mobility and photosynthesis?

At least among more complex organisms, I cannot think of any examples of highly mobile species (like animals) that also incorporate photosynthesis. Perhaps there are examples that I'm unaware of, but ...
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17 views

Synthetic carbon fixation pathways

Have there been carbon fixation pathways of, in particular, oxygen-producing bacteria, that have been replicated in the lab or at least the enzymes for the pathways have been successfully produced in ...
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64 views

Where is ATP used in Phosphorylation?

In the section describing the Calvin Cycle, under the subheading "Reduction", my textbook states that: The steps involve utilisation of 2 molecules of ATP for Phosphorylation... I could not get ...
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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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72 views

Why oceans are carbon sinks?

Building on this question, I understand pretty clearly why forests are carbon sinks (trees grow, and there is carbon stored in soil and biomass). What about the oceans, though? Are underwater ...
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Are trees the only source of large amounts of oxygen?

Trees use carbon dioxide and produce oxygen in the presence of sunlight. But is there any other source? If yes, are trees the most important source of oxygen, or is there any other source which ...
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31 views

Can photosyntetic cells be genetically modified to grow at a faster rate?

I hope the question is not silly, but I wonder if a sort of genetically modified plant "cancer" could be used for carbon sequestration. For example, cancer cells like HeLa have been reproduced in ...
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1answer
638 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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2k views

Can we harvest energy from plants?

This is a cross-cutting question but I think its core is about biology. Our society's need for energy is dramatically growing and we are messing up with our environment to answer them. Maybe another ...
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2answers
830 views

Do electromagnetic waves outside the visible spectrum have any role in photosynthesis?

Does photosynthesis occur only in the visible spectrum? If there is a way to completely remove all other electromagnetic bands from the sunlight, including infrared (IR), will photosynthesis continue ...
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How exactly is glyceraldehyde 3-Phosphate reverted to ribulose 1,5-bisphosphate for the continuation of the calvin cycle?

Around 6 molecules of G3P is produced at the end of the Calvin Cycle (light independent reactions of photosynthesis), and 5 of which are reverted back to RuBp. The general equation that I read is 5 ...
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87 views

How does CO₂ concentration affect photosynthesis?

I have heard the theory that with the increase of CO2 in the air, the speed of the photosynthesis would increase, thereby limiting the increase of CO2 levels. What is currently the rate limiting ...
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4answers
534 views

Why *morning walk*?

My PT teachers professes working-out/training in early morning hours is the best time to do so, a quick search on benefits of morning walk (or some similar phrase) reveals a lot of information which ...
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2answers
176 views

Photolysis of Water?

In chemistry, I studied the decomposition of water as being $2H_2O_{(l)} \rightarrow 2H_{2(g)} + O_{2(g)}$. However, when water is split, the equation is $2H_2O_{(l)} \rightarrow 4H^+ + 4e^- ...
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70 views

Are more molecules of ADP than inorganic phosphate returned to the light reaction in photosynthesis?

During the dark reaction, 9 molecules of ATP are consumed for every 3 carbon dioxide molecules, yet only 6 molecules of inorganic phosphate ultimately leave the cycle. Does that mean that there is a ...
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93 views

How Does NADPH Reduce 1,3-BPG?

If NADPH returns to being NADP+, then that means one proton and two electrons have been incorporated into 1,3-BPG. If only one proton and one electron were attached to the carbon in 1,3-BPG (removing ...
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1answer
55 views

Why are 2 electrons transported from photosystem II at the same time?

I only know that electrons are captured by the primary electron acceptor and then go through the electron transport chain, ultimately ending up at photosystem I. But why do 2 leave photosystem II in ...
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45 views

Decreasing Solubility as Solvent Moves Higher in Paper Chromatography

In paper chromatography, as the mobile phase (I used 1:9 acetone/petroleum ether) climbs higher and higher, will the solubility of the solutes decrease as the solvent moves higher? I speak mostly ...
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What Goes on in Photosystems at the Molecular/Atomic Level?

In light-harvesting complexes, how is the energy of a photon transferred from one pigment molecule to another? And in reaction-center complexes, how does the primary electron acceptor capture an ...
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1k 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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934 views

Why are there no known photosynthetic archaea?

I'm taking a microbial physiology course and we noted that, while some archaea are phototrophic, there are no known photosynethetic archaea. Are there any physiological characteristics that make ...
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264 views

Relationship between leaf structure and Photosynthesis rate

We can see numerous leaf structures in plant kingdom. As the leaves are designed for photosynthesis, their structure must be a factor for any optimization in photosynthesis or chlorophyll ...
6
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1answer
981 views

Which will produce more oxygen? Less number of (larger) trees or more number of (smaller) plants?

In a given area A, we have two choices - (i) we can plant maximum number of trees (which are larger in size) possible in A, say m OR (ii) we can plant maximum number of plants (which are smaller in ...
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2answers
143 views

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

If you took the chemicals a plant gains through photosynthesis and put it through the plants' roots or by injection, or used as a foliar application for intake through the stomata, would the plant ...
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153 views

What is the second phase of photosynthesis?

I really want to know what the second phase of photosynthesis (in the dark) is. I have a fair understanding of the first cycle where molecular oxygen is generated under the influence of light, but I ...
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106 views

Where can I get numerical data for the PAR (photosynthetically active radiation) curve?

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
699 views

What does “chlorophyll photosynthesis peak” mean in relation to photon wavelength?

When reading about how green / leafy plants work, I saw that they have chlorophyll A & B, which allow the plant to use the energy from light by capturing and transforming. When reading about ...
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52 views

How can oxygen production during photosynthesis be measured? [duplicate]

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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80k views

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 ...
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1answer
250 views

Do the light and dark reactions happen at the thylakoid?

My professor said that light reactions and dark reactions happen at the thylakoid. He did not choose the answer that "both reactions happen at chloroplast". Isn't the thylakoid a part of the ...
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423 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 ...
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2answers
543 views

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 ...
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4k views

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 ...
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2answers
7k views

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 ...
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120 views

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 C₄ pathway, the chloroplasts are dimorphic, that is, ...
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1answer
135 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 ...
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2answers
165 views

Is chloroplasts per cell indicative of the photosynthetic power of a plant?

Plant-A has on average N chloroplasts per cell. Plant-B has on average M chloroplasts per cell. If N > M, is plant-A more efficient in turning carbon dioxide into oxygen? Also, is it possible to see ...
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Can Galactose be synthesized with photosynthesis?

I know that galactose can be found in sugar beets and some gums so I thought plants could synthesize galactose but in my book the answer to the question "Which of these can be synthesized with ...
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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 ...
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Why does low temperature make RuBP, GP and TP concentrations fall in Calvin cycle?

In my A level revision guide and places on the internet it states that at low temperatures levels of RuBP, GP and TP all fall. However I don't quite understand how this is the case, because as far as ...