Questions tagged [membrane]

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6
votes
2answers
204 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 ...
6
votes
1answer
115 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 ...
5
votes
1answer
504 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, ...
5
votes
1answer
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 ...
4
votes
1answer
448 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 ...
3
votes
1answer
79 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−;...
3
votes
0answers
55 views

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 ...
3
votes
0answers
80 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? ...
2
votes
1answer
249 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 ...
2
votes
1answer
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 ...
2
votes
0answers
47 views

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, ...
1
vote
3answers
66 views

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 ...
1
vote
1answer
908 views

Why are the walls of the bronchioles folded?

The bronchiole shown in the section above has folded epithelium, why is this so?
1
vote
1answer
41 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 ...
1
vote
0answers
20 views

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'?...
1
vote
1answer
36 views

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, ...
1
vote
0answers
86 views

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, ...
1
vote
0answers
86 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 ...
1
vote
2answers
1k 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 ...
0
votes
1answer
16 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 ...
0
votes
0answers
18 views

Absorption vs Secretion

Qouted from Junqueira's Basic Histology textbook : "Ion and water transport across epithelia can occur in either direc- tion, depending on the organ involved. (a) Absorption is the pro- cess of ...
0
votes
1answer
511 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 ...