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16

Photosynthesis is nearly all visible light. There's usually not enough UV and thermodynamics more or less rules out infrared. Chris covered that pretty spectacularly, but that nearly is significant. There is some evidence that certain kinds of fungi can use gamma rays or other ionizing radiation for energy, but they're not particularly common. Melanin is ...


14

Photosynthesis only occurs in the visible light.have a look at the absorption spectra of the di fferent pigments involved in photosynthesis, you see that all these pigments absorb light between 400 and 700nm (from the here): You see that the absorption spectra of chlorophyll a and b are located from 400 to 500nm and again from 630 to 700nm. The maxima for ...


9

Yes, planting trees and burning them afterwards is a way to harvest energy from plants that's with us since millenia.


7

It is not possible to do this directly. Indirectly, it is possible, this is actually done by harvesting fruits - they contain the energy of the sunlight conserved in chemical compounds like sugars or starch and their cellular structures. The basic process for this is photosynthesis. The products from the fields are used technically to produce gas by ...


6

I found surprisingly little information about harvesting energy from photosynthesis Photosynthesis does not produce energy as such, it produces sugars/carbohydrates/chemical energy, which the plant then converts into energy via respiration. You can burn the sugar to produce heat. But this is basically what your doing when you burn a plant. So ...


5

The most basic example of what I would like to talk about seems to be the algae powered lamp that has (apparently) been developped. I think you misunderstood the idea. That lamp uses bioluminescence and not electric power. Normally living cells don't like to give you energy. The trick we use is anaerob fermentation. Without the presence of oxygen ...


5

The solubility of the solutes is the same at all points in the chromatography process. The solutes are clustered together at the beginning (at the solvent front) because none of them has moved very far yet. The reason for the separation of the solutes isn't that they become less soluble, it's that the solutes are moving at different speeds, like cars in an ...


5

You are missing some knowledge here for sure, photosynthesis is a little complicated at A level, so I will describe it in brief. During photosynthesis electrons and protons (A hydrogen atom without the nucleus) are required for a process called the electron transport chain and proton motive force. This happens during the light dependent stage of ...


5

The rate-limiting step of photosynthesis is the CO2 assimilating enzyme Rubisco (short for ribulose-1,5-bisphosphate carboxylase/oxygenase) (Jensen, 2000). It uses ribulose-1,5-bisphosphate and CO2 as substrates to generate glucose. Given that Rubisco is the rate limiting step in photosynthesis, an increase in its substrate CO2 would expectedly lead to an ...


4

Here's an overview of both the Light and Dark cycles of photosynthesis, which looked particularly useful to me as it shows that the energy-carriers ATP and NADPH2 generated through solar energy are used in the dark cycle to generate sugars. . Here is another one that shows more details on the precursors involved in the Calvin cycle: As commented by ...


4

You can say that but chloroplasts do not have uniform morphology across different species. Moreover some organisms such as red algae have chloroplasts of different origin. Real indicator would be lets say number of chloroplast ATP synthases and/or light harvesting photosystems; these can be perhaps indirectly approximated by the total surface area of the ...


4

The energy transfer is achieved by a process called "resonance energy transfer". It needs the positioning of the donor and the acceptor in very close proximity to each other - the light harvesting complexes are optimized for this. This allows the collection of small amounts of light energy and still enables photosynthesis. The figure shows how this works ...


4

There are photosynthetic archaea (such as Halobacterium) but the mechanism is different. They use rhodopsin-like ion pumps (bacteriorhodopsin and halorhodopsin) to move ions against the gradient and produce ATP via chemiosmosis (like mitochondria).


3

First thing to note is that the absorption spectrum of chlorophyll A and chlorophyll B is similar but not the same. The reason for the appearance of absorption spectra is because the light is composed of photons of light. Different photon has different oscillation frequency and energy. The essence of Chlorophyll absorption is absorbing photons. After ...


3

I cannot say anything about the general case, or specifically for day-neutral plants. However, Sforza et al. (2012) have studied the effects of light conditions on algae (used for biofuel production), and their results indicate several problems with continuous light. In continuous light conditions they find lower chlorophyll contents and higher carotenoid ...


3

As @wysiwig already pointed out the different morphology of chloroplasts is something that is hard to come by. This influences the amount of chlorophyll in these organelles which is the key for photosynthesis. So it is very difficult (to impossible) to compare chloroplasts of different plants as they differ pretty much. There is one paper from 1929 which ...


2

This question is related to the question: Why are some things transparent and others opaque? Being able to see something requires that it is opaque and that sufficient light illuminates it. UV and shorter wavelengths are not as prevalent as visible light on earth. The world would appear too dark to see if we used UV and shorter wavelengths. This is ...


2

A rule of thumb in optics is that light interacts with materials that have features with dimensions similar to the wavelength of light. For example, radio waves with large wavelengths interact with large objects like airplanes ,as in the case of radars, and really small wavelengths (x-rays & gamma rays) interact with really small objects like nuclei of ...


2

The biologist John Berman has offered the opinion that evolution is not an engineering process, and so it is often subject to various limitations that an engineer or other designer is not. Even if black leaves were better, evolution's limitations can prevent species from climbing to the absolute highest peak on the fitness landscape. Berman wrote that ...


2

I had to re-read your last sentence a few times to make sure I understood it correctly, but I think that now I do, and I can answer your question. What you're talking about are thermophiles. They're small organisms that love hot conditions - up to nearly 250 degrees Fahrenheit. They can be found places with a lot of hot water, such as hot springs - and, ...


2

Lets start with the absorption spectrum first (image from the Wikipedia page in chlorophyll): What you see in the figure is the absorption of light thoughout the visible spectrum by chlorophyll a (blue) and b (red). The higher the peaks get, the higher the absorption is. What we can see, is that chlorophyll absorbs light roughly until 500 nanometers (nm) ...


2

Water is split in chloroplasts in the light reaction of photosynthesis. Chlorophyll, acting as a photopigment, captures sunlight and transfers that energy to an electron pair of a water molecule. Under the influence of a water-splitting enzyme (George et al, 1989) it is separated into 2 protons, molecular oxygen and a free electron pair. Reference George et ...


2

1) Your understanding of taxonomy is outdated by a few hundred years. Linneaus' original system was based on flower morphology, but we since realized that the most effective taxonomy takes into account many different traits. In today's times, we mainly use DNA sequencing to determine relationships between organisms. 2) The leaf structure is not necessarily ...


2

Ignoring parameters such as: Leaf shapes Difference in photosynthetic efficiency due to other metabolic factors Unequal illumination of leaves Nutrient content of the soil Photosynthesis rate of a plant1 depends on the [total number of leaves] × [surface area of a leaf]. Assuming that a tree occupies same ground area as a shrub, there will be same ...


1

So refer to the following diagram, In the photosystem II complex, water is decomposed into oxygen and protons. That's two electrons liberated from each water molecule. Plastoquinone accepts two protons from the stroma by coupling it to the two electrons it receives from the photosystem complex. In this manner, the protons are transported to the lumen, and ...


1

I am going to play the devil's advocate here. I don't know if working out within the first three hours of waking is necessarily the best time to do so. In the morning, we have what is called cortisol awakening response which is where the body releases cortisol. Cortisol is a by product of the sympathetic nervous nervous system. Dr.s James E. Muller, ...


1

I can highly recommend Prof David MacKay's online book http://www.withouthotair.com/ where puts things into perspective. You can find him on YouTube and TED too. e.g. http://www.withouthotair.com/c18/page_103.shtml "Can we live on renewables" POWER PER UNIT LAND OR WATER AREA Wind 2 W/m2 Offshore wind 3 W/m2 Tidal pools 3 W/m2 Tidal stream ...


1

Another alternative is using plants to generate biomasse using photosynthesis and letting bacteria convert that into electricity. There is research being done about this method and you can read more about it on the following websites: http://www.plantpower.eu/ http://plant-e.com/technology.html


1

The light dependent reactions involve an electron transport chain with enzymes embedded in the thylakoid membrane. NADPH and ATP are generated in the stroma and water is oxidized in the thylakoid lumen. I'm not sure if it's correct to say that the light independent reactions occur "at the thylakoid" since, in plants, they could really occur anywhere in the ...


1

Energy from an electron transport chain is used to actively transport protons from the stroma to the thylakoid lumen. Thus the lumen has a relatively higher proton concentration and therefore a lower pH than the stroma. Higher $[H^+]$ means lower pH. Lower $[H^+]$ means higher pH. Keep in mind that the flow of actively transported protons from the stroma ...



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