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Questions tagged [membrane]

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Why don't membrane potentials violate the principle of electroneutrality?

The principle of electroneutrality states that the number of anions and cations in a solution must be the same, i.e., that there will be no charge excess in any side of the membrane separating two ...
TheAnonymous's user avatar
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1 answer
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Does this explanation hold good even in case of Mitotracker red?

When the fluorescence intensity is higher when the depolarization is high? The more damage to the mitochondria, the more mitochondrial dysfunction and therefore more fluorescence intensity. So, in ...
user76965's user avatar
2 votes
1 answer
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Why is iron transported across membranes in the ferrous form?

Iron in the diet of animals is predominantly in the ferric form, but it must be reduced to the ferric form by a specific ferrireductase before it can be transported across the cell membrane into the ...
Karthikeyan's user avatar
5 votes
2 answers
1k views

Where in the cochlea are frequencies below 200 Hz detected?

I understand that different frequencies are detected in different positions along the cochlea. I'm also aware that the range of human hearing is roughly between 20 Hz and 20 kHz. However, looking at ...
Hoff's user avatar
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Number of membrane proteins of a particular type per cell

Is it possible (or meaningful) to count how many proteins (protein copy number?) of a certain type a given cell has on its surface? For instance, say there is some membrane integral protein ...
Dunois's user avatar
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How are Current Sources and Sinks for Postsynaptic Potentials defined?

I am currently reading "Electric Fields of the Brain" by Paul Nunez, and encountered this passage: The synaptic inputs to a neuron are of two types: those that produce excitatory ...
Abundance's user avatar
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How fast do ions move in body when they go in and out of the cell membrane?

Do we have any measurement tools to measure the speed of ions moving in a human body, specifically going in and out of the cell membrane? Do we have any tools to know where an ion is at a specific ...
PhysicsSolvesAll's user avatar
1 vote
1 answer
54 views

Where are the ATP synthases synthesised? [duplicate]

The nano-machinary of energy production ATP synthase is well known to exist on mitochondrial inner membrane and chloroplasts. But how and where are they formed or synthesised ?
Sarika's user avatar
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3 answers
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Are there any drugs that target the lipid envelope of viruses?

Many drugs go after the unique viral enzymes but do any target their lipids? Viral membranes are of course similar to the host membrane but might have a different composition and do have a different ...
SeanJ's user avatar
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1 answer
564 views

Parietal and Visceral epithelia

If you google visceral and parietal you get: The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the ...
Alara's user avatar
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0 answers
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Difference between infectivity and cell fusion abillity of Virus. (COVID 19)

I'm a computational chemist who have interest in COVID-19. As a physical chemist, I'm lack of basic knowledge for biology. What is the difference between 'infectivity' and 'membrane fusion activity'?...
user59027's user avatar
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Nernst equation and equilibrium potential

Solutions A and B are separated by a membrane that is permeable to Ca2+ and impermeable to Cl−. Solution A contains 10 mM CaCl2 , and solution B contains 1 mM CaCl2. Assuming that 2.3 RT/F = 60 mV, ...
Lia Ahmed's user avatar
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3 votes
1 answer
180 views

What is the basis of the endocochlear potential?

I am learning about the endocochlear potential. According to different sources, the ionic composition of perilymph is about as follows (in mM): 150 Na+, 4-5 K+, 1.2 Ca2+, 1 Mg2+, 120 Cl−, and 20 HCO3−;...
Jimmy's user avatar
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2 votes
1 answer
679 views

Plasma Membrane Proteins and Cytoskeletal Attachment

Regarding membrane protein functions, which of the following statements is CORRECT? a. Membrane proteins are responsible for both cell to cell recognition and cell anchoring and are ...
Stefan 's user avatar
7 votes
2 answers
420 views

How do membrane proteins find their target locations?

The question might be asked for any kind of "bound" proteins, but I'd like to restrict it to membrane proteins. Assuming membrane proteins (or their main parts) don't (or aren't) build in situ but at ...
Hans-Peter Stricker's user avatar
5 votes
1 answer
751 views

Rate of Diffusion Through Cellulose Membrane

From what I understand, the larger the molecular size, the slower the rate of diffusion and vice versa. However, after doing a lab (similar to this one) about diffusion through a cellulose membrane, ...
bioguy's user avatar
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1 answer
1k views

Why does the mass increase in this question? [closed]

So, on 'http://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2016/june/AQA-BL3HP-QP-JUN16.PDF', question 1.b., they show a partially permeable bag of glucose solution, in a less concentrated ...
Piomicron's user avatar
3 votes
0 answers
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Movement of few ion during changes in membrane potential

My question is very simple: why is it sufficient for a very few ions (such as 1 in 100000 K+) to move across the membrane to generate a remarkable variation in the membrane potential (like a change of ...
Ginevra B's user avatar
1 vote
1 answer
2k views

Why are the walls of the bronchioles folded?

The bronchiole shown in the section above has folded epithelium, why is this so?
Taimur's user avatar
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1 vote
0 answers
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Potentials between endolymph/cytoplasm and endolymph/perilymph

I am studying for an exam and there is something I can't seem to understand. My textbook says that the endolymph contains 150mM potassium, 2mM Na+ and 130mM Cl-. The perilymph contains 5mM potassium, ...
Marina's user avatar
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2 votes
0 answers
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Potential between endolymph/cytoplasm and endolymph/perilymph [closed]

I am studying for an exam and there is something I can't seem to understand. My textbook says that the endolymph contains 150mM potassium, 2mM Na+ and 130mM Cl-. The perilymph contains 5mM potassium, ...
Marina's user avatar
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6 votes
1 answer
129 views

Do free computer programs exist that can simulate drug permeability in bacterial membranes?

I am currently trying to make derivatives of a molecule in hopes of making it more permeable to bacterial membranes. I wanted to know whether there are any bacterial membrane simulating programs where ...
helpantibioticswinagain's user avatar
1 vote
2 answers
2k views

Difference between water and tea [duplicate]

My friend heard that tea is worse for drinking than water because "cells have a special membrane and tea has special supplements and membrane doesn't let tea pass and this is why skin is dry even when ...
biologyquest's user avatar
1 vote
0 answers
136 views

Effect of increasing Extracellular Na+ Concentration on resting voltage and likelihood of an action potential of occuring

If you increase the extracellular Na+ concentration how will this effect the resting voltage and likelihood that an action potential of will occur? Please explain using the Goldman–Hodgkin–Katz ...
John Musser's user avatar
2 votes
1 answer
3k views

When does DIFFUSION occur and not OSMOSIS, and the otherwise?

For example, I do know that red blood cells have both the Na+/Cl- co-transporter and Aquaporin (water channel) that allows both Na/Cl and water molecules to pass through. But why in biology textbooks ...
franciscaxyz's user avatar
5 votes
1 answer
2k views

How do nuclear membranes form during Telophase of Mitosis/Meiosis?

During Telophase, homologous chromosome pairs reach the poles of the cell with the help of microtubules. From there, nuclear membranes form around each new set of chromosomes. My confusion originates ...
puradox's user avatar
  • 151
1 vote
1 answer
52 views

Ways to cause membrane damage to microalgae and yeast?

I am researching a way to monitor the membrane damage of cells. To do that I fist have to have reference points, namely, cells with damaged membranes. I am working with Dunalliela, Hematococcus (both ...
Keine's user avatar
  • 155
4 votes
1 answer
633 views

Do cell membranes have more phospholipids in one layer than in the other?

Assuming the cell membrane to have a spherical shape, geometry tells us that the area of the inner leaflet is smaller than the area of the outer due to the difference in radius between them. Does this ...
BioE's user avatar
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3 votes
0 answers
83 views

Can the Donnan effect be reversed so phospholipids follow ions? [closed]

I know that there are flipases and flopases that facilitate this sort of thing, but I'm curious about other possible influences. Can the Donnan effect be reversed so that phospholipids follow ions? ...
Jasand Pruski's user avatar