Questions tagged [cell-membrane]

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

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The following information should be used to answer the following questions [closed]

Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or nonfunctional. Chloride ion channels are membrane structures that include which of the ...
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Why is the cell membrane protective?

Generally in biology books, it is written that the cell membrane is selectively permeable at that it has a protective function, as if here It says that the cell membrane protects the cell from its ...
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What recovers normal polarisation after hyperpolarisation?

I have been taught that a $\ce{Na+/~K+}$ pump helps to recover normal polarisation after-hyperpolarisation in neurones. I could not find out how it does that, since I've also been taught that such a ...
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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 ...
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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 ...
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Do SARS-CoV-2 virus particles really 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 ...
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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 ...
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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 ...
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Are nucleic acids found in cell membranes?

I've found various results online and I was recently marked in on an important test as wrong when I made the assumption they were not found in the cell membrane. Does anyone know what the correct ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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/...
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What are the secondary structure requirements for cell-penetrating peptides AKA protein transduction domains

Cell penetrating peptides. Cell penetrating peptides (CPPs) are a class of short amino acid sequences which are sufficient for crossing cell membranes and delivering themselves along with any attached ...
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What's the meaning of 'plasma' in 'plasma membrane'?

I wonder why is it called plasma membrane - what's the biological meaning of the word 'plasma'?
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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 ...
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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, ...
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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!
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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 ...
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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 ...
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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 ...
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Difference between going against and going down a concentration gradient

The difference between facilitated diffusion and active transport is that facilitated distribution occurs down a concentration gradient and active transport occurs against a concentration gradient. I ...
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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 ...
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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 ...
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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....
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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How does cholesterol affect the fluidity of a plasma membrane?

I was previously taught that cholesterol affects the fluidity of a plasma membrane. At high temperatures, cholesterol decreases fluidity and at low temperatures cholesterol increases fluidity. The ...
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What is the difference between filopodia and lamellipodia?

I'm rather new to biology (I'm an applied mathematician) and I'm currently studying models of Notch-Delta dynamics between cells with filopodia and lamellipodia. What is exactly the difference ...
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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.
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Do all transmembrane proteins contain channels or tunnels?

In my book, there is written something like this. The integral proteins pass into the lipid bilayer to different depths and establish hydrophobic bonds with lipid molecules. Some of the integral ...
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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 ...
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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 ...
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What does “PDPN+ cells” means?

Are they podoplanin positive cells (cells that tested positive for podoplanin)? "...though it has been shown that podoplanin (PDPN+) cells analogous to mouse FRCs are found in human secondary ...
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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?
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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 ...
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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 ...
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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 ...
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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", ...

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