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

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593 views

What is the relationship between UV wavelength and penetration depth into human skin?

Some background - Some recent research has strongly suggested that UVA penetration into the skin is far more dangerous than UVB, a very good example is this paper by Agar et al. (2004). My query is, ...
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1answer
35 views

What does these $\Delta \Delta G$ numbers signify?

I was reading a paper and came across this table showing $ \Delta \Delta G$ numbers of different nucleotide sequences in DNA/RNA. I know that $\Delta G$ is free energy and $ \Delta \Delta G$ is ...
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2answers
32 views

How to conceptualize the action potential?

In my AP Biology class, we were taught that action potentials are not electrical impulses in the same way current travels through a wire. Rather, we were taught that action potentials are changing ...
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1answer
29 views

What governs the distribution of blood vessels?

Whenever someone is sick, doctor places 2 fingers on wrist & observes the heart-beat-rate by feeling pulses of a certain artery. To me it seems the distribution of blood vessels are pretty ...
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1answer
89 views

How to determine whether the energy of a stem-loop fold is significant or not?

If I have a predicted RNA stem-loop of energy -0.30 kcal/mol, and another of -4.9 kcal/mol, how do I tell whether such a structure is a significantly stable structure or not? Our two competing ...
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1answer
46 views

Is there any knowledge of physics can be applied in to evolution?

I have asked a similar question in Biology.SE (What physics knowledge can be applied to biology of organisms and ecosystems?), but it just about organisms and ecosystems, not evolution. After watching ...
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1answer
35 views

What is the biding site code recognized by the parts of the spliceosome

Another question about another Youtube video. At 0:50, the splicing process begins to remove the non-coding section of the DNA (intron), so the different parts of the spliceosome attach to the borders ...
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1answer
290 views

Are Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70 positively charged or negatively charged? [closed]

Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70,are they positively charged or negatively charged ? And which other solvents can be used as a substitute to water for preparing solutions in each ...
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1answer
335 views

What is the difference between rheobase and threshold?

Neuronal tissues can be excited by electrical stimulation. Two commonly encountered characteristics for electrically stimulating nerve cells is the threshold and the rheobase. My question is what the ...
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1answer
41 views

Kinesin-5 / cytoplasmic dynein spatial density distribution in neurons

Is there some way to experimentally determine the density distribution of Kinesin and Dynein in a Neuron? Fluorescence labeling would be impossible(?) as GFP markers would probably alter the motor ...
2
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1answer
35 views

Muscle force/energy relationship

I found the Hill muscle model, which helps relate the force a muscle can generate to its change in length over time (its "contraction velocity"). Is there a similar model to get an idea of the energy ...
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1answer
37 views

Protein Conformation Modeling

I'm interested in learning about computational modeling in biophysics. I have heard some amount about people modeling proteins as a network of ideal springs to examine things like conformation ...
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1answer
42 views

What's the best way to measure/calculate the size of a light beam at the sample of a microscope?

I am using a microscope with an LED derived light through the epi-fluorescent port of a microscope. I know that the "field of view" for a given objective is equal to the field number/magnification ...
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36 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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3answers
220 views

Action Potential Distribution On Synapses

This is a biology+physics question. Since there is no biology section, I am asking here. In brain, when a neuron reaches to threshold value, it fires an action potential. In most graphics, that is ...
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1answer
93 views

How to estimate the DNA density in human sperm head? [closed]

I have got an estimate of sperm head volume from internet.Like consider it as a disk of order 4-5µm. Now I wanted to find the DNA density in the sperm head. How to find that?
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2answers
53 views

Useful physical information of a protein

Beside energy and heat, I don't know any useful physical information of a protein. Can you help me list some of it. Somethings like Fourier-transform infrared spectroscopy to provide protein structure ...
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2answers
62 views

Which types of hydrogen bonds are known to exist in RNA secondary structures?

I'm programming an implementation of an algorithm for pattern matching in RNA structures. The algorithm assumes the following types of base pairs: Plain: No base pairs (just the primary structure of ...
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1answer
177 views

What is the energy balance of cooking?

If I cook some food, I get apparently several energetic advantages: thermal : the temperature of the food is closer or superior to the temperature of my body or internal organs, so I do not have to ...
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1answer
60 views

How to measure the total number of cells in an average human body?

I have got one assignment to calculate the approximate sum total of all cells in the human body. How to tackle this problem? I know that the current statistics is $10^{13}$ cells. I wanted some hints. ...
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1answer
71 views

How Ants know about Earthquake?

How does an ant know about Earthquake is it because of an organ or due to other factors?
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1answer
27 views

Nervous System : Signal Translation

If a device were created to monitor the nervous signals from the heart, including stable heartbeats, rapid heartbeats, etc., and this device were capable of transmitting the "stable heartbeat" to the ...
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1answer
68 views

What is the strength of human cornea?

What is the difference of pressure a human eyeball cornea (cornea, lens and other elements separating vitreous body from air) can handle? Or asking differently: what the outside pressure should be to ...
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1answer
142 views

How to manufacture different sized micelles in nano -scale?

I am trying to answer q5: "How can you manufacture micelles in A) nanometerer -scale B) and in ten nanometer -scale?" My Thinking Observations and some thinking Oil in ...
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0answers
26 views

Explanation of ECG in MI using an electrostatic model

I found a paper presenting an electrostatic model to explain the ECG recorded in various leads. This model essentially calls for considering the depolarization wavefront to be the major contributing ...
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0answers
39 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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1answer
48 views

How non-invasive blood glucose concentration measurement work? [duplicate]

Diabetes patients need to conduct the “fingerstick” a few times a day. One of the mechanisms of "fingerstick" is to take small amount of blood sample and put it onto a test strip. The enzyme on the ...
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26 views

How is saltatory conduction faster than conduction of unmyelinated fibers? [duplicate]

It's always the same explanation that currents are able to "hop" along Ranvier nodes instead of passing continuously along the axon making saltatory conduction more efficient than continuous ...
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1answer
77 views

How non-invasive blood glucose concentration measurement work?

Diabetes patients need to conduct the “fingerstick” a few times a day. One of the mechanisms of "fingerstick" is to take small amount of blood sample and put it onto a test strip. The enzyme on the ...
0
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0answers
20 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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44 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 ...