The use of methods from the physical sciences to aid in the study of biological systems.

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119 views

What keeps the resting potential of neurons constant at -70 mV?

I know the sodium-potassium pump pumps out 3 Na+ ions and pumps in 2 K+ ions per reaction so the negative charge in the axon increases. However, once the voltage (difference of charge inside and ...
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85 views

What is the transmembrane 'Positive-Inside Rule' nowadays? Has the definition changed over time?

First definition. Two publications by von Heijne in 1989 and 1992 coined the 'Positive-Inside rule' and showed it's practical value in topology prediction of transmembrane helices. It was clearly ...
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20 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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38 views

Infrared emitting diode eye safety

I'm thinking of creating my own laser tag system and am a bit concerned about the eye safety aspect. Most of the homebrew system I've seen use the TSAL 6100 ...
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40 views

How to get a pdb file of a single atom?

I am trying to get a pdb file that contains a single atom, it doesn't matter if it's Hydrogen or another atom. How can I obtain this? Are there any pdb files with just a single atom available to ...
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18 views

Role of microvilli in cell volume regulation

Does the presence of microvilli on a cell's surface ensure that it's more resistant to cell swelling or lysis in a hypotonic solution, as compared to a normal cell?
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8 views

Interaction study of oligomeric proteins

I'm dealing with two different protein(say, protein_a and protein_b) which stays in an interacting-oligomeric form in biological system. I have so far successfully been able to purify both the ...
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30 views

How spermaceti makes a whale float

In the biochemistry book I'm reading (Box 10-1, Lehninger Principles of Biochemistry), an example is given in whales of how spermaceti (a wax located in the whale head), when at sea level is a liquid, ...
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234 views

How can the directionality of a protein structure be defined?

For a DNA molecule, you can define directionality using the convention of a 5'-3' direction on the Sense strand. However, using an N to C convention for a protein doesn't work since the ends may be on ...
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24 views

Meaning of 'forms of free energy'?

I was doing a practice exam paper and it asked for different 'forms of free energy'. I am a physicist rather then a biologist so 'free energy' to me means Gibb's Free Energy: $$G=H-TS$$ But I cannot ...
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18 views

Is it possible to biologically convert potential energy to chemical energy?

To lift an object x meters it is necessary to expend, at a minimum, an amount of energy corresponding to the increase in that objects potential energy associated with the increase in height. When ...
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23 views

What are some commonalities between biology systems and semiconductor physics?

It seems that fundamentally both neural system and semiconductors are operating using similar principles on the same scale. Things such as drift and diffusion current plays major role in both systems. ...
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49 views

Unexpected stoichiometry n in ITC experiments

I'm looking at the binding of a small molecule to several RNA constructs and tried to determine the binding constants. To do this I've performed a few ITC experiments on this system, the results were ...
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Do a patient's cells have a higher or lower resistance to hemolysis?

There is this answered question in my book, but I don't understand the solution. A sick patient's blood cells have hemolysis in a NaCl solution 5g/l and in normal people blood cells hemolysis happens ...