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Questions tagged [spectroscopy]

Questions relating to how biological systems interact with electromagnetic radiation.

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What happens to the absorbed blue and red light in the chlorophyll molecule?

If the chlorophyll molecule (its chromophore) absorbs red and blue light and reflects green light, shouldn't the absorbed blue and red light be emitted back when its excited electrons relax?
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27 views

How do carbon 13:12 ratios confirm the biological origin of oldest microfossils?

I was reading this article about how Schopf and Valley’s findings in 2017 confirmed that the 3.5 billion–year-old microfossils found in the Apex chert of Western Australia are indeed remnants of ...
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1answer
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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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0answers
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What absorbs light at 380 nm in a sample of DNA oligonucleotide extracted from a PAGE gel?

I have extracted DNA oligonucleotide of size 77 bp from a crushed 10% PAGE gel using 3 rounds of $\ce{LiClO4}$ in water. The extracted elute was dried down in a vacuum centrifuge to a certain volume ...
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3answers
215 views

Using nanodrop for analysing biological samples other than nucleotides

I am a 3rd timer postdoctoral fellow with some experience in molecular biology and biochemistry, but major skills in Zoology and Natural History. I am studying some natural extracts, and isolating ...
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2answers
996 views

Why do most plants reflect green and others other colors?

I have read that chlorophyll absorbs red and blue. As shown in detail in the absorption spectra, chlorophyll absorbs light in the red (long wavelength) and the blue (short wavelength) regions of ...
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2answers
922 views

If you measure the O.D. of cells at one wavelength, is it possible to find its equivalent O.D. at another wavelength?

For example, I measured the optical density (O.D.) of some cells at wavelength 550 nm but I should have used 600 nm. Is there a way of converting my O.D. to its equivalent in another wavelength?
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What will CD spectroscopy show when L- and D- forms of proteins are mixed?

What will happen if equimolar concentration of L- and D- forms of proteins are mixed and we take the circular dichroism reading? Will the positive and negative ellipticity cancel each other out or ...
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1answer
765 views

How can I calculate alpha helix content from molar ellipticity?

How can I calculate the alpha helix content (i.e. percent) in a protein from a given molar ellipticity of 222 nm, without using any software. I have tried the Greenfield-Fasman equation, but the ...
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0answers
47 views

Spectroscopy on plant leafs

I'm trying to do spectroscopy readings on plants where I shoot electromagnetic waves and look at their signature/profile. I want to be able to do this at a distance, in the field and on live plants ...
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1answer
76 views

Is galvinoxyl antioxidant assay possible using NMR spectroscopy?

I would like to perform an antioxidant assay using the galvinoxyl protocol. The protocol states that we need EPR spectroscopy, but only NMR spectroscopy is available at my institution. Is there an ...
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1answer
113 views

NMR spectroscopy detection methods for proteins

I've stumbled upon a table comparing the sensitivities of different detection methods in NMR spectroscopy: "Direct", "DEPT" and "Inverse", where "Inverse" seems to be the most sensitive. What exactly ...
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223 views

RMSD during conformational transition in proteins

When I was investigating the differences between protein structures obtained by X-ray crystallography and NMR spectroscopy, I found the paper [1] compairing structures of several proteins resolved ...
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2answers
609 views

What is a good non-fluorescent DNA dye?

Can anyone suggest a dye which specifically targets DNA, but is not fluorescent? We plan to mark DNA before observing it with RAMAN-Spectroscopy. Because of the weak signal, even a low emission would ...