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

learn more… | top users | synonyms

11
votes
3answers
179 views

Is the amount of the soil reduced when plants grow?

According to the principle of mass conservation I think the amount of the soil should be reduced when plants grow. But this reduction is not observable so much. For example, some trees (big trees) ...
1
vote
0answers
29 views

Natural rulers: What organisms have the most regular size?

What organisms exhibit the most precise length scales? E.g. are there trees with rings that are of very precise thickness, or single celled organisms which are all very nearly the same length? In ...
1
vote
0answers
10 views

Membrane resistance of a neuron

I am about to simulate a neuron activity with the "Leaky Integrate and Fire" neuron model. But for that I need the membrane resistance. I was really looking a lot online, but I just cant find a value. ...
0
votes
1answer
18 views

Why is nitrogen isotopic labelling required for protein NMR?

Why is labelling required for Nitrogen (by 15N) for studying structure of a protein using NMR?
4
votes
1answer
42 views

Why does migration distance depend on log of molecular weight in SDS-PAGE?

I really want to know why in the result of SDS PAGE, log of molecular weight(MW) and migration distance (distance from the loading well) have a linear relationship. Why is it log(MW) instead of MW? ...
3
votes
0answers
20 views

Phase Transitions of Purified Proteins

Why do solutions of purified protein condense into droplet phases? I'm trying to understand the protein phase transitions. Here is the article http://www.cell.com/cell/fulltext/S0092-8674(12)00634-4#...
0
votes
1answer
25 views

Enzymes and Reversibility of Reactions

Richard Feynman mentions in the third chapter of The Feynman Lectures: So the real system is in the GDP-GTP transformation; in the dark the GTP which has been stored up during the day is used to ...
2
votes
0answers
41 views

Do trees have genes for stopping the grow?

Do trees have genetically encoded to stop growing at some height, to keep dividing the cells only to a certain amount, or to pump nutritions only till it's advantageous because they've already ...
4
votes
3answers
67 views

Is Einstein's mass energy equivalence ($E=mc^2$) relevant to biological systems?

I'm more than 100% sure that the kilograms I eat don't get directly converted to feces and urine. I'm sure some of it goes to regenerating tissue that is constantly being disposed as well, and maybe ...
1
vote
0answers
10 views

How does a higher channel density increase speed of propagation of an Action Potential?

If there is a higher density of sodium channels then there will more Na+ flux in the cell. So it's like trying to pass more material through a pipe and therefore the speed of action potential (AP) ...
1
vote
0answers
28 views

What exactly is the time constant of an ion channel gating?

Let's take a channel that does not get inactivated, but is only in open and closed states. I understand what m (activation variable) represents. It's the fraction of the gates open. But what does t(...
2
votes
1answer
82 views

Why don't membrane proteins move?

I understand that based on their tertiary structure, intrinsic proteins have hydrophobic non-polar R-groups on their surface and that they 'interact with the hydrophobic core of the cell membrane to ...
3
votes
1answer
45 views

Why is statistical mechanics relevant to RNA and protein folding?

This is a very naive question. As far as I understand the folding of a molecule is governed by the electromagnetic forces between its atoms and also between its atoms and the atoms in the surrounding ...
0
votes
1answer
29 views

Enzyme kinetics: recommended literature to grasp the concepts better

I have had a few biochemistry courses, but I still feel confused and a bit scared each time they try to explain and apply enzyme kinetics or even chemometrics in different situation during class. On ...
0
votes
0answers
10 views

Detecting brainwaves with no direct contact and no electrodes

Brainwaves are low frequency waves which is hard to detect and can be interfered with radio waves.i heard that it is possible to detect it with radio telescope and can be analysed with computers and ...
1
vote
1answer
32 views

Difference between pulse coupling and diffusive coupling In biological oscillators

What are the differences between pulse coupling found among neuron cells and diffusive coupling found in cells that exhibit calcium waves? Moreover, in both methods, is it a strict requirement that ...
2
votes
1answer
61 views

Optimizing Gel Electrophoresis: Ampere, Volts and Buffer concentrations

I am a master student in biochemistry, and I have used gel electrophoresis many times before. What I want to know is how one should adjust the mA (mAmpere) compared to the voltage and the buffer one ...
1
vote
1answer
39 views

Question about radiation and how it affects biological systems

I'm doing research on the effects of radiation, and specifically UV, X-Ray and Gamma radiation, on biological systems at the cellular level and beyond. I understand that radiation types can be ...
0
votes
0answers
15 views

Killing water-born pathogens with vacuum

Can water-born pathogens be killed by applying a vacuum to a body of water, causing it to boil at room temperature? Do most pathogens contain enough gaseous molecules that the expansion of the gas due ...
4
votes
1answer
185 views

How's the membrane potential restored to resting state after hyper polarisation?

I have known for so long that Na+/ K+ pump restores the membrane potential. But as it pumps in 2 K+ for every 3+ Na+ moving out how can it make the membrane potential less negative when the net result ...
4
votes
1answer
53 views

How can space-time affect ageing? [closed]

I recently watched the movie -"interstellar" and I came through the question that how can ageing be affected by space-time? Wherever I look, I get it as a fact that it's kind of ageing slows down in ...
2
votes
1answer
179 views

What are wave frequencies in the EEG?

Here is a typical EEG reading: I understand that each row corresponds to the signal read between two sensors on a standard 10-20 (or 10-5) distribution setup (e.g. ...
3
votes
2answers
350 views

Confusion about resting membrane potential and the Na/K pump [duplicate]

To this day, very few people and sources have been able to clear up my confusion about resting membrane potential and how it is maintained. It seems like this is one of those topics that few people ...
1
vote
0answers
31 views

Why do the vines change their spinning direction?

Look at the vines holding onto the lattice. The "vine springs" change their spinning direction in the middle. Why? And how do they achieve this? (By the way, what's the name for this plant? Is is ...
2
votes
2answers
54 views

Diffusion coefficient of cells in blood?

What's the diffusion coefficient of white cells in blood? Is it well defined, or are cells too large and few as to be treated as particles in this context? P.S. I have tried to look this up, but what ...
4
votes
1answer
34 views

How is green fluorescent protein distributed while inside an organism?

I would like to know a relatively simple thing, but something I wasn't finding the answer to. When fluorescent protein is used in a relatively large, non-transparent animal, like a mouse, or ...
4
votes
1answer
81 views

What causes the opaque green colour in Lepidoptera?

Link here to what I mean by 'opaque' colouration on the insect, the colour intensity remains constant despite changes in light intensity and angle (not shown by the picture but the moth exhibits this ...
2
votes
1answer
61 views

Why is stimulation of nerve tissue with a negative pulse called “cathodic” stimulation?

By definition, the cathode is defined as the terminal through which current exits a polarized device. But in the context of neuromodulation, such as spinal cord stimulation, deep brain stimulation, ...
2
votes
1answer
68 views

What is membrane-partitioning free energy? Can it be simulated?

Firstly, is there a strict definition of the "membrane-partitioning free energy"? It is banded around in membrane biology, but I have never seen it strictly defined. The only non-scholarly site that ...
3
votes
2answers
88 views

How can neuronal signals faithfully be reproduced by scalp electrodes?

There is a skull barrier (and possibly other layers too) between the brain and the scalp. I have seen people trying to extract EEG signals from the scalp by connecting electrodes and interface it to ...
3
votes
1answer
70 views

How does heat generated by metabolism differ compared with heat generated through exercise?

I am from a mathematical background so I don't have much knowledge on biology. I'm building a mathematical model to predict heat generation with parameters of metabolic heat generation and exercise ...
3
votes
1answer
548 views

Relationship between turgor pressure and osmotic pressure?

I would like to know if there is a relationship between osmotic pressure (inside and outside of a cell) and turgor pressure. If so, is there a way to formalize it mathematically? Thank you in advance,...
8
votes
1answer
72 views

How does membrane potential vary between intraceullar membranes and the cellular membrane?

Question Does each type of membrane have a different membrane potential? I'm especially interested in answers that can cite academic papers that have attempted to measure membrane potentials. ...
3
votes
0answers
20 views

What are necessary parameters for a tissue scaffold to be biodegradable?`

I am a mechanical engineer with little biological experience, but I have recently been looking at tissue scaffoldings. My current understanding is as follows, but may be flawed. I would appreciate ...
2
votes
1answer
154 views

Are there any theories using thermodynamics/statistical mechanics or information theory principles to modelling in ecology?

So far, I've only known one: the MaxEnt theory. It uses the maximum information entropy developed by information theorist, which in turn inspired by the thermodynamics from physics, to predict the ...
2
votes
0answers
18 views

How to use the law of diffusion in the presence of electric forces?

Isn't the movement of ions affected by the electric field as well? For instance, when a sodium channel in a cell's membrane opens, the sodium ions are said to diffuse into the cell, from higher ...
7
votes
2answers
106 views

Permeability of Plasma Membrane

I’m having trouble grasping why small polar molecules can cross the hydrophobic region of the membrane and not ions. Won’t the polar molecules be attracted to the watery extracellular medium and not ...
3
votes
1answer
76 views

Why does the direction of endolymph flow oppose direction of body motion?

In the semicircular canals, the endolymph always flows in a direction that is opposite to the motion of the vestibular apparatus itself. I’m having trouble grasping why this is, and I would greatly ...
1
vote
0answers
64 views

Absorbed dose from a CT scan with relation to radiation accidents

I read somewhere that the average CTDIvol in CT scans at hospitals is ~40 mGy. This translates to the 'radiation intensity' at the center of the person, and can also be roughly interpreted as an '...
3
votes
2answers
57 views

Is there a way to know how many sodium channels are active (conducting) at a given time in the brain?

I was doing some reading about anti-epileptic sodium channel blockers, then wondered how many sodium channels are actually conducting (actively passing ions) at any given time, that is, in an "average,...
1
vote
0answers
31 views

What is the sedimentation coefficient of Mycoplasma?

I have attempted to find the sedimentation coefficient of a number of bacterial species, namely E. coli and a number of Mycoplasma species, but they seemed to be rather elusive in the literature. If ...
2
votes
1answer
109 views

Dwell time equations for ATP-sythase?

I have read that every 120 degree rotation of the F1 complex of ATP-synthase can be split into a 30 degree rotation and a 90 degree rotation. In between these two are dwell times, the one before the ...
5
votes
2answers
117 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?
9
votes
2answers
2k views

Why are potassium channels slower than sodium channels?

I am relatively new in the subject of biology. I have a strong mathematical background and in order to get into the field of computational neuroscience, I am trying to get some biological background. ...
1
vote
0answers
53 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 ...
1
vote
0answers
25 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 ...
2
votes
0answers
17 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 ...
3
votes
0answers
24 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 ...
3
votes
1answer
139 views

Can geckos climb a wet surface?

We know geckos can climb vertically or even upside down a surface like glass. But can they do that on wet glass?
3
votes
2answers
1k views

How does Bernoulli’s Principle apply to the cardiovascular system?

Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system. It makes sense that velocity and cross-sectional ...