Questions tagged [cell-membrane]

A selectively-permeable biological membrane that separates the interior of all cells from the outside environment.

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

Why do most negatively charged phospholipids concentrate in the inner leaftlet?

Due to the asymmetry of the lipid membrane, negatively charged phospholipids such as phosphatidylserine, phosphatidylinositol are concentrated in the inner leaflet, creating a different charge ...
0
votes
0answers
13 views

Question on steroid hormones [duplicate]

I have learnt that there are 2 types of hormones: peptide hormones (hydrophilic, mostly bind to receptors on cell membrane) steroid hormones (hydrophobic, can pass through cell membrane and bind to ...
0
votes
1answer
35 views

Why doesn't the polar side of the plasma membrane block nonpolar diffusion?

It is often stated that small molecules or nonpolar molecules can diffuse through the plasma membrane because they can pass through the middle nonpolar bit, but why don't the polar sides block these ...
1
vote
2answers
43 views

What are the differences in ultrastructure of cilia and flagella?

Cilia and flagella are aimed for similar perpose, motion. And both of them show the (9+2) microtubule arrangement. They are nearly identical in structure. But to be more specific , where exactly does ...
0
votes
0answers
10 views

Through what mechanism does cholesterol act as a stabilizing agent and why does it depend on temperature?

As I understand it, at higher temperatures cholesterol has a tendency to make the membrane less fluid, and at lower temperatures it makes it more solid. My question is, what mechanisms causes this? At ...
2
votes
1answer
34 views

Giving a sign to Pressure Potential, Osmotic Potential And Other Similar Quantities

When these quantities are mentioned with what reference do we give signs to them? Why is Osmotic Pressure positive, but Osmotic Potential, negative? What about Turgor Pressure (Pressure exerted by the ...
1
vote
1answer
72 views

How is the cell membrane protective?

Generally in biology books, it is written that the cell membrane is selectively permeable and that it has a protective function, as in here It says that the cell membrane protects the cell from its ...
0
votes
0answers
20 views

EM field in living organisms and tissue resonance frequency

I have two questions which I can't find enough information about, and I would be very grateful if someone could give me a lid to the answer: As far as I know, if we accelerate charged particle it ...
0
votes
0answers
31 views

Effect of opposing electric charges on cells

Is the affect on a cell between two negatively charged plates theoretically similar to between a positively and negatively charged plate? In other words, would it induce charges on the inside and ...
2
votes
0answers
61 views

Are SARS-CoV-2 virus particles really able to travel through filopodia and “emerge from the tips”?

Watching the new University of California San Francisco video Coronavirus forces cells to produce tentacle-like structures that infect neighboring cells I saw The growths spread out, and ...
2
votes
1answer
49 views

What is the exact definition of mitochondrial depolarization?

As I understand as per literature reading and some khanacademy(https://www.youtube.com/watch?v=PtKAeihnbv0&t=315s): Proton gradient := the gradient created when hydrogen ions moves to the ...
4
votes
1answer
82 views

How does the DNA cross through bacterial cell wall during electroporation?

There exists a lot of literature on electroporation of Gram-positive and negative bacteria. Most of it gives an explanation that electroporation works by creating transient pores in cell membranes of ...
0
votes
0answers
19 views

Adding potassium outside of neuron: Hyper- or De- polarization?

At rest, the equilibrium potential for potassium given by the Nernst equation is ~ -80mV. Since the cell is mainly permeable to potassium, this is the reason for the cell membrane's rest potential to ...
0
votes
0answers
38 views

Why does insertion of transmembrane domains occur in the rough ER?

To elaborate on that question, why in the secretory pathway does the insertion of transmembrane domains into the membrane occur in the rough ER as the protein is translated and threaded across the ER ...
-1
votes
1answer
47 views

Why viruses “die” outside the host? [duplicate]

Why viruses "die" outside the host after sufficient time? I want to know the biological process behind it. What role being exposed to air plays in virus destruction? What role sunlight plays in the ...
0
votes
0answers
23 views

Does the cell release the empty capsids?

The virus via the spike of the capsid connects to a receptor in a cell, then the DNA enters the cell wall. My question is what happens to the capsid - does it stay connected to the receptor or is ...
6
votes
1answer
126 views

What is the lipid membrane of SARS-CoV-2 made of?

SARS-CoV-2 is an enveloped virus: in structural diagrams it is drawn with membrane glycoprotein (M), envelope protein (E) and spike protein (S) embedded in a lipid membrane. What specifically is the ...
0
votes
1answer
35 views

What are the short/long term effects of chloroquine on fundamental cell processes?

Does chloroquine, which affects the endosomal membrane traffic pathway (by affecting the acid environment used for fundamental endosomal reactions), have short/long-term effects on cell growth/...
3
votes
1answer
77 views

Proteoglycans vs Glycoproteins

On the left, is my histology book, on the right there's qoura (the internet). My histology textbook says that "unlike glycoproteins, proteoglycans have attached GAGs which often comprise a greater ...
1
vote
0answers
22 views

Help me understand Voltage Patch Clamping please?

Before I type my question it is important to know that I already tried looking this up on my own and could not find an answer because the answers are all in complicated physics terms and this topic is ...
0
votes
1answer
71 views

Why don't carrier proteins require energy to change shape?

I know that carrier proteins can be used for both passive and active transport, but I am referring to the facilitated diffusion aspect. Even though facilitated diffusion via carrier protein goes along ...
0
votes
1answer
31 views

Are ligand gated channels saturable?

A major difference between simple diffusion and facilitated diffusion is that facilitated diffusion has a maximum transport and velocity; the rate of diffusion is limited, whereas in simple diffusion, ...
1
vote
0answers
18 views

How does a protein molecule enter a cell through the cell membrane? [closed]

I can't find a good explanation as to how a whole protein molecule enters a cell membrane. Is it through endocytotic vesicles, with the help of ATP? How does this occur? Thanks for the help!
0
votes
0answers
21 views

Osmotic gradient across cell membranes

In a typical cell in the human body, is the intracellular fluid typically hyper- or hypoosmotic to the extracellular fluid, e.g., is the osmolality of cytoplasm higher or lower than that on the ...
3
votes
1answer
46 views

How are lipid-coated mRNA-based vaccines transported into cells for expression?

In CNN's video Scientist says Coronavirus vaccine could be ready by 2021 after about 00:25 'Robin Shattock, the Head of Mucosal Infection and Immunity at Imperial ...
0
votes
0answers
17 views

Outlining cell edges of an epithelium

Is there any free software (for Windows, preferably) to detect cell edges in pictures of an epithelium, for example? I know Packing Analyzer does this, any other suggestions? Ideally, I would like ...
0
votes
0answers
32 views

Why don't membrane-bound cells frequently collapse or spill their contents?

According to the fluid mosaic model, cells that are bound by a phospholipid bilayer membrane are divided from the environment by a rather thin boundary. Some compare the membrane to a soap bubble. If ...
1
vote
0answers
13 views

How are newly synthesised proteins targeted to the plasma membrane?

There does not seem to be a definitive answer to how proteins destined to be intrinsic plasma membrane proteins are directed there. Presumably, assuming starting at a cytosolic ribosome, the pathway ...
1
vote
0answers
41 views

What makes iodine an effective antiseptic?

I'm thinking about tincture of iodine, potassium iodide (Lugol's), and povidone-iodine (PVP-I) specifically, which, as is my understanding, work by solubilizing elemental iodine in an aqueous solution....
1
vote
1answer
36 views

What happens to embedded membrane proteins after a vesicle is formed?

When an animal cell is going through endocytosis it cell surrounds a food particle, and the membrane swallows it, creating a vesicle within the cell. However, what happens to the embedded ...
0
votes
1answer
26 views

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)?

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)? The vaping illnesses that have been happening on the news in the United States are being caused by the federal ...
3
votes
0answers
89 views

Why don't all my cell membranes “smush” when I fall?

I've read the question about cell membranes breaking apart, which is close to what I'm asking, though I'm trying to probe a bit deeper. I understand that there are hydrophobic forces keeping the cell ...
0
votes
0answers
5 views

How are filopodia and membrane lengths related

I wonder how cell protrusions, in particular filopodia, form and how much of the cell membrane do they use. Is new membrane formed whenever a filopodium is created, or is the membrane simply deformed ...
2
votes
0answers
35 views

Do carrier proteins constantly open and close or do they only work when a substance binds to them?

What causes carrier proteins to change shape ? Do they need energy to change shape? If that is true, how are they involved in Facilitated diffusion ? By changing shape, do we always mean opens from ...
1
vote
2answers
76 views

When is voltage generated across a membrane?

I'm very confused so bear with me please. Electrogenic pumps are carrier proteins that generate voltage through the movement of ions, right ? When is a voltage generated ? When there's a net ...
-2
votes
2answers
62 views

Protein rafts over the Phospholipidic bi-layer

Does any of you know the specific name of the protein rafts that allow proteins to float over a double layer of phospholipids, (cell membrane)? I just feel there should be another name rather than ...
0
votes
0answers
20 views

same osmotic pressure of different solution

For example, There is a sugar solution with concentration $A_{1}$, how to determine the concentration of a NaCl solution which produce same osmotic pressure as the previous sugar solution toward ...
1
vote
0answers
47 views

How does the glycocalyx of cells attach together if they are negatively charged?

Context Thus, the entire outside surface of the cell has a loose carbohydrate coat called the glycocalyx. The carbohydrate moieties attached to the outer surface of the cell has several important ...
5
votes
1answer
633 views

Is plasma membrane permeable to sucrose

I searched a lot in the net but don't found a clear answer. I just want to know if plasma membrane is permeable to sucrose.
2
votes
0answers
46 views

Pharmacokinetics and cell-membrane permeability of Adenosine triphosphate disodium hydrate

【My Question】 (1) Please tell me the pharmacokinetics of this ATP (or Adenosine triphosphate disodium hydrate) when it is administered orally or intravenously. In particular, Does this material has ...
2
votes
0answers
23 views

What is the end-point of material from an apoptotic cell, after phagocytosis?

Apoptosis occurs. The organelles and interior material form apoptotic bodies that are packed in vesicles. The cell membrane breaks apart (cell no longer exists) and apoptotic bodies enter the ...
-1
votes
1answer
32 views

Can monoclonal antibodies work only if the target of it is located in the cell's surface?

Can monoclonal antibodies work only if the target of it is located in the cell's surface? or it can be used to targeting a protein located inside the cell?
2
votes
0answers
32 views

Osmosis/ Facilitated diffusion

Water can move across the (Semipermeable non polar lipid) membrane by simple diffusion (osmosis). But polar molecules cannot pass through the non polar lipid bilayer, they require carrier proteins to ...
6
votes
1answer
191 views

Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?

A canonical statement I have frequently read is that "large diameter axons conduct action potentials at faster velocities than small diameter axons". After recently learning the effect of increased ...
1
vote
0answers
46 views

Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows: Say we have the minimum charge input, "X", ...
1
vote
0answers
88 views

What is the difference in the electrical excitability between a “large diameter soma” and a “large diameter axon”

There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons: Large diameter axons propagate action potentials more quickly than small diameter ...
5
votes
1answer
72 views

At What Rate Do Ions Leak Out of a Plasma Membrane Segment That Has No Ion Channels?

In reading about the purpose of myelin during action potential propagation, I came across a point of confusion. From what I understand, one of the primary "benefits" of myelin is that it aids in ...
0
votes
1answer
87 views

What are the (evolutionary) advantages of secondary transport?

Secondary active transport uses electrochemical gradients as a source of energy for the uphill transport of substrates (coupled to downhill transport of the ion). However except for in a few cases (e....
4
votes
1answer
63 views

Can sperm cells penetrate the cell membrane of non-ovum cells?

Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell ...
1
vote
0answers
22 views

Reference request: Lipid composition in bacterial, yeast and human membranes

I would like to know about the lipid composition of different kinds of cellular membranes. I remember going through such a table once in a paper, but I am unable to find it anymore. What I am looking ...

1
2 3 4 5