Biology Forums - Study Force

I would like to know on whether far-red light plays any role on controlling cell growth and division or not.

Does anyone have any suggestions?
Thanks in advance for any suggestions

What type of cells are you curious about, oem7110?

Such as bacteria, virus, and plants' cell ...
Do you have any suggestions?
Thank you very much for any suggestions :>

On non-photosynthetic bacteria it wouldn't have an effect, but I can see it having an effect on photosynthetic organisms. This article provides evidence of such effects, though it's locked from public visibility:

http://link.springer.com/article/10.1007%2FBF01276831

Some pages are provided, however, and I've included them below

Moreover, some sources state that it also increases the production of certain chemicals found in plants, like gibberellin

UV-C light is effective in destroying nucleic acids and breaking apart germ DNA. With their DNA broken, they can't function or reproduce and the organism dies.
https://www.phonesoap.com/how-does-uv-light-clean

Referring to above statement, blue light is closer to UV-C than red light, so red is less destructive than blue on destroying nucleic acids and breaking apart germ DNA. Based on this assumption, it is hard to distinguish on whether (red light increase cell growth and division - case 1) or (less blue light exists to interrupt cell reproduce, so cell growth and division gets better - case 2).

Do you have any suggestions on which case to explain cell growth and division better?
Thank you very much for any suggestions :>

If I were to assume, I don't think any visible light would have damaging effects on any photosynthetic species. Given that the sun emits light of all colors, and that this same light is visible anywhere on the planet, the question is why would plant species evolve different? The only type of photosynthetic species I can think of that would have to evolve differently to accommodate for different light intensities are plants that grow underwater, like seaweed. Maybe certain light waves cannot penetrate as deeply as others; however, that doesn't mean if they were exposed to the spectrum that was lacking, that they'd get damaged. The only waves I would be fearful of damaging DNA is UV light. Anything in the UV spectrum is dangerous for DNA. When you say blue and red, are you referring to the UV spectrum?

(https://biology-forums.com/gallery/47/6_09_02_16_10_29_04.png) (https://biology-forums.com/index.php?action=gallery;sa=view&id=23373)

I refer to the visible light spectrum.  Referring to your given articles, it did not specific enough to distinguish on whether (red light increase cell growth and division - case 1) or (less blue light exists to interrupt cell reproduce, so cell growth and division gets better - case 2).

Do you find more articles related to this issues?
Thank you very much for any suggestions :>

I just don't think there is research that tests whether visible light damages DNA. Like why would visible light impede the cell cycle? That's why I'm confused with your request

I think there is not much scientific researches on this issue at this present moment, until our society starts to measure light spectrum from space everyday, and report them like today's weather report.
Thank you very much for suggestions :>

How would light in outer space differ than that found on earth. I'd assume that outer space has more UV radiation, making it harder for plants to grow.

Check out this article

https://en.wikipedia.org/wiki/Photoprotection#Photoprotection_in_Plants

Referring to following articles, I would like to know on what problem is for not able to converting the energy of the UV photon into heat within human body, which would lead to the generation of free radicals or other harmful reactive chemical species.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>


Photoprotection in Humans

Photoprotection of the human skin is achieved by extremely efficient internal conversion of DNA, proteins and melanin. Internal conversion is a photochemical process that converts the energy of the UV photon into small, harmless amounts of heat. If the energy of the UV photon were not transformed into heat, then it would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).

In DNA this photoprotective mechanism evolved four billion years ago at the dawn of life.[7] The purpose of this extremely efficient photoprotective mechanism is to prevent direct DNA damage and indirect DNA damage. The ultrafast internal conversion of DNA reduces the excited state lifetime of DNA to only a few femtoseconds (10−15s)—this way the excited DNA does not have enough time to react with other molecules.

For melanin this mechanism has developed later in the course of evolution. Melanin is such an efficient photoprotective substance that it dissipates more than 99.9% of the absorbed UV radiation as heat. [8] This means that less than 0.1% of the excited melanin molecules will undergo harmful chemical reactions or produce free radicals.

Post Merge: 8 years ago

The process of Sunburn would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).
I would like to know on which process to generate free radicals, would it be Apoptosis?

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>


Due to the excellent photochemical properties of DNA, this nature-made molecule is damaged by only a tiny fraction of the absorbed photons. DNA transforms more than 99.9% of the photons into harmless heat[3] (but the damage from the remaining < 0.1% is still enough to cause sunburn).[1] The transformation of excitation energy into harmless heat occurs via a photochemical process called internal conversion.


Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, commonly from the sun.  Moderate sun tanning without burning can also prevent subsequent sunburn, as it increases the amount of melanin, a photoprotective pigment that is the skin's natural defense against overexposure. Importantly, both sunburn and the increase in melanin production are triggered by direct DNA damage. When the skin cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the skin is replaced.

https://en.wikipedia.org/wiki/Sunburn

https://en.wikipedia.org/wiki/Direct_DNA_damage


Apoptosis (from Ancient Greek ἀπόπτωσις "falling off") is a process of programmed cell death that occurs in multicellular organisms.[2] Biochemical events lead to characteristic cell changes (morphology) and death.

https://en.wikipedia.org/wiki/Apoptosis

Why are we talking about photoprotection now? The question was, do certain wavelengths of light *improve* cell division. Photopertection has to do with plants, and how chlorophyll protects the cells. UV light is different than visible light. We all know UV light damages DNà.

We all know UV light damages DNA, and since there is not much researches on how different visible lights affect on cell division, I can only further discuss based on following assumption:

UV light (left of light spectrum) is closer to blue light (middle of light spectrum)  comparing with red light (right of light spectrum), so based on energy levels, red is less destructive than blue on destroying nucleic acids and breaking apart germ DNA.

Based on this assumption, I would like to know on how the process of Sunburn generates free radicals within human body.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

(https://biology-forums.com/gallery/47/6_09_02_16_10_29_04.png)

Let's look at this again. My assumption is that anything within the UV range is dangerous AND the closer the wavelength is to x-ray, the more penetrating it is, and therefore more damaging. The formation of free-radicals occurs in plants, if I recall correctly, and they are prevented by certain pigment molecules like carotenoids - that's where photoprotection comes in.

Are you certain of this:

Referring to following statement, logic imply that Sunburn would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>

If the energy of the UV photon were not transformed into heat, then it would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).
https://en.wikipedia.org/wiki/Photoprotection

Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, commonly from the sun.
https://en.wikipedia.org/wiki/Sunburn

Unless you can provide a source for this, it's hard to confirm.

Some sources state that sunburns offer free-radical protection - the opposite of what you're proposing. The formation of free radicals occurs in *plants* because during photosynthesis, water is split into oxygen and protons (H+). This splitting of water and the exposure of oxygen is a gateway for free-radical formation. This is not the case in animals.