Questions tagged [biophysics]

The use of methods from the physical sciences to aid in the study of biological systems. Note that biophysics questions are only allowed if they are mainly about physics.

Filter by
Sorted by
Tagged with
0
votes
0answers
13 views

Efficiency formula in Environment-assisted quantum transport (ENAQT)

I'm currently studying the book quantum effects in biology, in particular, I'm interested in the phenomena of Environment-assisted quantum transport (ENAQT) in photosynthesis. In ENAQT, they discuss ...
1
vote
3answers
45 views

How come light in the Violet spectrum looks like a mixture of Red and Blue, even though they are of different wavelength? [duplicate]

How come pure monocromatic light in the violet spectrum is perceived by us as light that is a superposition of 2 other, different wavelength light. is there some scattering process in the eye that ...
-1
votes
1answer
58 views

What can make nuclear radiation dosimeter increase $\rm 0.2μSv/h$ suddenly? [closed]

I got one nuclear radiation dosimeter, with national official verification certificate (legal effect). dosimeter specifics: Detector: Energy compensated GM counter tube Detectable species: Beta Gamma ...
0
votes
1answer
70 views

Does brain activity generate anything outside our bodies? [closed]

I have been reading recently about the Law of Attraction and while I don't believe in its 'scientifical' basis it did make me think about whether our brain produces any kind of activity strictly ...
0
votes
1answer
59 views

Why was RGB chosen as the basis / primary color set for pixels?

Human eyes have retinal cells that are sensitive to red, green, and blue light. Pixels on electronic screens use the same three colors to produce many apparent colors. But a little thought (and ...
1
vote
0answers
48 views

How to derive the Potts model as well as the gauge transformation *directly* from the principle of maximum entropy?

$ \newcommand{\delim}[3]{\left#1#3\right#2} \newcommand{\delimzero}[3]{#1#3#2} \newcommand{\delimone}[3]{\bigl#1#3\bigr#2} \newcommand{\delimtwo}[3]{\Bigl#1#3\Bigr#2} \newcommand{\delimthree}[3]{\...
0
votes
2answers
109 views

Atom or Cell? Which is the basic unit of life? [closed]

As it is said that everything in this universe is made up of atoms and molecules and atoms are called the building blocks of matter. But then why the cell is called the basic unit of life, why not ...
0
votes
0answers
16 views

What concentrations of negative organic ions ($\rm mmol / L$) are needed to keep these liquids neutral?

The current does not flow spontaneously through the cell membrane. This means that the fluids outside and inside the cell are electrically neutral. What concentrations of negative organic ions ($\rm ...
0
votes
2answers
49 views

What scientific evidence is there for the definable real world quality of redness independent our perception? [closed]

With light poise and counter-poise, Nature oscillates within prescribed limits. Yet thus all arise the varieties and conditions of the phenomena which are present to us in space and time. - Goethe ...
1
vote
0answers
10 views

Photosynthesis relation to work function and photoionization

When photosynthetic organism’s use pigments such as chlorophyll, the metal ion in the center emits an electron after absorbing a specific wavelength of light, at 400-700 nm This does not make sense to ...
1
vote
1answer
101 views

Are there physical reasons for breaking this symmetry in biological systems?

For some reasons, it seems that particular "handedness" are chosen by nature, because we have the prevalence of some enantiomer, that have different optical properties respect to ...
-1
votes
2answers
73 views

Did we adapt to Earth or Earth to us? [closed]

I often hear that Earth is a unique planet because it has life and it has its own inhabitance. We also see a proper balance between plants and humans and other animals. Why life is not possible on ...
2
votes
1answer
35 views

Can a Cochlear implant impart superhuman hearing? [closed]

The bandwidth of human hearing determined by empirical data is $20 \; Hz$ to $20 \; kHz$. A cochlear implant stimulates the auditory or acoustic or Cochlear nerve directly so that the hearing can be ...
0
votes
1answer
38 views

What are the technological limitations of DNA computing? [closed]

IBM and Microsoft are studying the application of DNA computing, but I was wondering what are the technological limitations that prevent it from being used in the same way as a conventional digital ...
1
vote
0answers
60 views

Does physics allow for many competing biologies or only one biology? [closed]

Does physics allow for many competing biologies or only one biology? I read sci-books about life based on silicon and I've read an article that said that other structure than DNA can encode genetic ...
37
votes
12answers
6k views

Does physics explain why the laws and behaviors observed in biology are as they are?

Does physics explain why the laws and behaviors observed in biology are as they are? I feel like biology and physics are completely separate and although physics determine what's possible in biology, ...
-1
votes
4answers
43 views

Calculating work done or energy expended difference in two biomechanics examples [duplicate]

I have a biomechanics question regarding how much work is done (or energy consumed) by a person moving at a constant speed from point $A$ to $B$. In the first scenario, $A$ to $B$ is $100 \; \text{m}$...
2
votes
1answer
16 views

Upconversion Particles in Biological Tissues

So I was learning about upconversion particles in biological tissues and understand mainly how they work. UV-Vis light are scattered and absorbed by tissues, so we instead send near-infrared light to ...
0
votes
0answers
8 views

Is there a table for hyperfine interaction tensor?

I'm doing research in biophysics and I need to find the hyperfine interaction tensors for ascorbic acid radical, FADH-, and oxigen radical (O2-). Is there a place where I can find the hyperfine ...
0
votes
0answers
39 views

Discriminate closed-chain from open-chain

I have two classes of chains: closed-chains where a random path ends near where it starts (ie. loop), and open-chains without this restriction (ie. random walk). These chains are a directed graph ...
3
votes
2answers
106 views

To grow one $\rm m^2$ of crop plants, how many $\rm m^2$ of solar panels do you need?

In vertical farms you need to use LEDs to make plants grow, which in turn have to be powered e.g. by solar panels. If solar panels had the same efficiency as plants, then you would need the same ...
0
votes
1answer
60 views

I don't understand an equation of motion (for biological cells)

In a paper about cell dynamics (pdf) I cannot understand equation (3), because there is an 'arcsin' of a vector. Let $\theta_i(t)$ be the orientational angle for cell number $i$ at time $t$, $\vec{n}...
0
votes
1answer
36 views

Why is Earth's atmosphere made almost entirely of $\rm N_2$ and $\rm O_2$ molecules rather than any of the nitrogen oxides?

I assume the formation of $\rm N_2$ and $\rm O_2$ molecules is energetically favorable compared with N2O, NO, and NO2, etc., but are there some more intuitive arguments regarding the bonding and ...
2
votes
2answers
109 views

What does “entropy” really mean?

I'm currently taking a course of introduction to biophysics in college and we currently covered a subject called entropy (S). We did some maths based on the Carnot cycle and came up with the following ...
1
vote
1answer
122 views

Cannibalism and energy conservation [closed]

This question in biology forum asks why cannibalism is not an evolutionarily stable situation. In this respect one has to distinguish occasional and exclusive cannibalism - in the latter case one ...
1
vote
1answer
43 views

What causes pain when experiencing a static shock? [closed]

What exactly causes the pain in my fingertip when I get a static shock from touching something? Is it the current flowing through my nerves or is it a localized thermal burn from the spark itself?
1
vote
1answer
51 views

How do plants absorb different “rates” of light?

Context I'm trying to understand the broader question of why plants are green despite our Sun's "green" star status. This Wired article has a nice explanation, but I don't understand the key ...
3
votes
1answer
57 views

Why is the energy required to bend a flat bilayer membrane to vesicle independent of its radius?

Imagine that we have a flat bilayer sheet (let it be a disc-shaped bilayer) lipid membrane. When I naively think about this system being bent to form a vesicle (closed bilayer membrane), my intuition ...
1
vote
1answer
32 views

Using Persistence length to establish straightness of position data

In the following picture I am showing 3D position data for 4 different tracks just to illustrate how the tracks looks like. As we can see that we have all kind of behaviors occurring from helical ...
0
votes
2answers
143 views

What happens to the energy when I push my hand against a wall but there is no displacement? How to calculate it? [duplicate]

If I push my hand against a wall, the wall doesn't move, so there is no displacement and so no work done. But energy is being used to generate the force, so what is happening to the energy? Does that ...
1
vote
0answers
34 views

Does membrane permeability affect the equilibrium reached by two different concentrations of equally charged ions?

I'm asking this question to aid understanding of the formation of membrane potential in a cell from electrochemical gradients of ions e.g. why the membrane potential is skewed towards the equilibrium ...
7
votes
0answers
82 views

Beam stiffening when twisted

For a particular cylindrical beam that is bent and twisted, its bending stiffness is found to increase with twist. I have a limited knowledge of continuum mechanics. Can the theory explain this, ...
0
votes
0answers
36 views

Has there been any development regarding lifelike helical dust structures? (Tsytovich et. al. 2007)

Tsytovich et. al. 2007 proposed that some interaction of dust and plasma might produce inorganic lifelike structures. Has there been any development regarding such theories?
2
votes
0answers
54 views

What is the physics behind why incorrect cuff size for measuring blood pressure manually or automatically lead to inaccurate results?

The biophysics behind measuring systolic and diastolic blood pressure manually with a cuff and stethoscope is that Determine the approximate pressure it takes for the cuff to occlude the brachial ...
2
votes
4answers
196 views

Can viruses be in a superposition? [duplicate]

I know that atoms and entire molecules and even sets of hundreds of molecules can be in superpositions of position eigenstates. Viruses are the smallest living organisms (if they can even be called ...
-1
votes
1answer
229 views

Physically, how does erection work?

All articles I found explain a human male erection through biological mechanism. However I am still curious how such process can make the male sexual organ "stand up" during an erection. ...
2
votes
2answers
74 views

When I just move my hands around, how is the momentum being conserved?

I guess when I'm moving my hands around, the electrostatic potential stored in the chemicals in my body is converted to motion of my arms? But what about momentum conservation? I think the brain sends ...
1
vote
0answers
108 views

What modern mathematics/theoretical physics can one use in mathematical biology/biophysics, especially genetics and high resolution microscopy? [closed]

I’m interested in theories involved or would be involved in current or near-future biophysics/mathematical biology, so I’m wondering that 1.what modern mathematics/theoretical physics one can use in ...
-2
votes
2answers
153 views

How important is floating-point precision in molecular dynamics?

I'm wondering how important floating-point precision is in numerical simulations of molecular dynamics in biology. From what I understand, molecular dynamics programs like NAMD use 32-bit floats to ...
0
votes
3answers
116 views

Why we only see black colour when there is no light? [closed]

pls help me on it. I do not know if it is right but why do we only see black colour while there is no light.
-1
votes
2answers
137 views

How do I calculate the effort force exerted by my hands while holding a high plank? [closed]

This high plank is an example of a 2nd class lever. The fulcrum is at the feet, the load is at the centre of gravity of the body, and the effort is at the hands. If I know: My weight (the load force)....
0
votes
1answer
105 views

IR and UV transmissivity window of the (human) eye

Given this image: I just assume that the eye is made out of glass, so I wonder how is it that IR and UV radiation is absorbed by it? I would understand one of them but why is it transmissible for ...
0
votes
2answers
89 views

Trying to figure out the mathematics behind the classical superhero lift-by-the neck [closed]

I recently got into a debate about the classical villain or hero move of lifting an adversary by the neck. We've all seen the one-arm or even two-arm lift and i made the case that even two arms ...
4
votes
4answers
94 views

Do adjacent sarcomeres oppose each other during contraction?

A sarcomere is the contractible portion of the muscle cell. And here is a figure of three sarcomeres in series before and after contraction: I was taught that the thick fiber, myosin, pulls on the ...
2
votes
1answer
47 views

What is the entropy difference between $n$ free-floating amino acids and $n$ amino acids that have been translated into a protein?

Is there any known calculation for the (~ average) change in entropy between $n$ free-floating amino acids in a cell, at typical physiological concentrations, versus those same $n$ amino acids after ...
4
votes
1answer
40 views

Non-Conservative Potential for Charged Residues in Proteins

I am struggling with this question. I want to determine whether the potential of a protein is conservative or not if its dielectric constant depends on the local density of the protein. My model only ...
5
votes
4answers
97 views

By what mechanism is a growing tree root able to lift heavy concrete pavement?

A tree root lying under several square meters of 100mm thick concrete pavement can cause the pavement to lift up as it grows. What forces are involved in creating this lift? I vaguely understand that ...
0
votes
2answers
70 views

In what situations do throwing an object use less energy than carrying it? [closed]

This relates to humans carrying or throwing rocks, so it relates both to mechanics and biophysics. Let's say you stand at point A where there is a pile of rocks. You need to get the rocks to point B. ...
1
vote
3answers
120 views

How does a spectrum analyzer works. Example with particular case: eyes [closed]

[edit]: I reformulated my question to first talk about general spectrum analyzer and then ask about how vision works (which is a particular case of spectrum analyzer as I explain below). Let's assume ...
0
votes
0answers
26 views

What equation can we use to describe flow through a thin mask with through-holes?

What equation can best describe the flow of water through holes (500um) within a thin mask (200um)? I don't think the Hagen–Poiseuille equation applies here, since the hole size is big relative to it'...

1
2 3 4 5
12