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

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18 views

Do we perceive contrast colour patterns easily because of adaptation? [migrated]

I can understand that colours are just manipulation of our brain to light rays of different frequencies, amplitude, and wavelength. But we do feel easier to find a pattern on a thing which is of ...
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1answer
33 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 ...
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31 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 ...
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3answers
55 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 ...
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16 views

What is a good HADDOCK score?

I am using the HADDOCK docking server. I am attempting to dock a protein to some dsDNA. All the energy values stack up, but I'm having trouble interpreting the more specific scores. My HADDOCK score ...
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0answers
7 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) ...
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1answer
60 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 ...
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18 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 ...
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30 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 ...
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41 views

Why do electrophoresis gel boxes only have 1d wire electrodes and not a 2d 'mesh' as used in clarity?

Since the DNA and protein are electrophoresed in a 2D plane (along one dimension, the length of the gel), I am surprised that a 1D wire electrode is used for anode and cathode, and not a 2D mesh-like ...
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329 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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1answer
508 views

What is the difference between organelle membranes?

Cells and organelles are contained in lipid bilayers. I'm particularly interested in eukaryotic organelle bilayers and the biophysicochemical differences between them. Many papers assume a ...
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1answer
25 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 ...
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1answer
27 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 ...
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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 ...
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1answer
43 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 ...
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1answer
33 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 ...
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2answers
335 views

How do diving marine mammals avoid decompression sickness?

How do marine mammals, whose very survival depends on regular diving, manage to avoid decompression sickness or "the bends?" Do they, indeed, avoid it?
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14 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 ...
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1answer
101 views

Software recommendation for protein in electric field modeling? [closed]

I'd appreciate a suggestion for software to compare models of two proteins in an alternating electric field. The more detail, or perhaps direction towards an existing and similar paper, the better. ...
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1answer
102 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 ...
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1answer
290 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 ...
3
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1answer
66 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 ...
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1answer
2k 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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109 views

Criteria for compound action potential thresholds

As opposed to action potential thresholds (which are binary yes/no events), electrophysiological thresholds of compound action potentials are arbitrary. Mostly a certain noise level is picked and when ...
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1answer
129 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. ...
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2answers
68 views

What are some 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
269 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 ...
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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 ...
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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 ...
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1answer
33 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 ...
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1answer
78 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 ...
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2answers
356 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
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1answer
53 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, ...
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7k views

Why is saltatory conduction faster than continuous conduction?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
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2answers
81 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 ...
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2answers
114 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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2answers
96 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 ...
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1answer
377 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 ...
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1answer
62 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. ...
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2answers
431 views

Can a living organism run on electricity?

Each time I'm too lazy too cook I think it'd be cool to be able to just plug myselt into an outlet. Yet I know it is not possible - I need amino acids and a lot of other stuff that electricity can't ...
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0answers
18 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 ...
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1answer
152 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 ...
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0answers
17 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 ...
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1answer
268 views

Effect of pupil responses on the electroretinogram

The electroretinogram (ERG) is a measure of electrical activity of the retina. It is typically recorded from the cornea with a wire electrode or gold-foil electrode. Generally, the the ERG is ...
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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
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1answer
61 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 ...
2
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1answer
108 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 ...
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21 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 ...
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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. ...