Questions tagged [cell-membrane]

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

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corona viruse vs the Plasma Science (Mehran Tavakoli Keshe methode) [closed]

I have seen one video in telegram which is about weak the viruses energy, by this information: Reminders and practical advice to apply GaNS Using simple tools and materials from around the ...
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Cell Membrane : Channel Proteins

The integral membrane protein and the protein channel is a part of the cell membrane? Is this correct or not?
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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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Why do synergids lack cell wall on their chalazal end? [closed]

I've heard that synergids lack cell wall only on their chalazal end. Why is it so? Also, why does the egg (in an ovule) has its wall thicker towards the micropylar end?
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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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Number of phopholipid bilayer membrane an oxygen molecule diffused through [closed]

What is the minimum number of layers of phospholipids that a molecule of oxygen passes through when diffusing from the alveoli, through cells, to haemoglobin in the red blood cells? The answer to this ...
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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 osmotic pressure equals to turgor pressure in a fully turgid cell? [closed]

When a cell is fully turgid, its walls and membranes are completely stretched. At this time osmotic pressure of thecell will be equal to turgor pressure
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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 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 ...
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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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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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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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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 called the glycocalyx. The carbohydrate moieties attached to the outer surface of the cell has several important ...
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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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Which proteins can lose adherence to cell surface by energical agitation?

According to this link https://www.cell.com/cell-reports/pdfExtended/S2211-1247(14)00121-1 CD44 protein lose adherence to cell surface by energical agitation Apart from CD44, which proteins can lose ...
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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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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 ...
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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....
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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 ...
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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 ...
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Why can small polar molecules (e.g. carbon dioxide) diffuse through the phospholipid bilayer of cell membrane? [duplicate]

Polar molecules cannot diffuse through the phospholipid bilayer because they get repelled by the hydrophilic fatty acid tails of the phospholipids. But why can small polar molecules diffuse through?
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222 views

What is the difference between a signal peptide and a transit peptide?

From what I know, the two names are used interchangeably and I haven't found any resource which says otherwise either. Is there at all any difference, is there a transit peptide that is not a signal ...
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What regulates cyclic AMP?

After reading a textbook chapter on GPCRs I am still confused by what regulates cAMP. I took in my notes that cAMP is made by adenylyl cyclase and destroyed by cAMP phosphodiesterases (also another ...
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What do the text annotations in an electron micrograph mean?

I saw a photograph taken from an electron microscope, with some text. I want to know what is the meaning of these numbers and letters? Thank you! Regards.
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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 ...
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What is the electric field strength of microalgae?

Question: What is the electric field strength of microalgae? Background: So I have been having some problems with fungi contaminating my chromera velia algae cell cultures. I haven't determined what ...
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Neuronal membrane resting potential for large cells

I'm reading Medical Physiology by Boron and Boulpaep (a really terrific book). In the chapter Electrophysiology of the Cell Membrane, section Membrane Potential Is Generated by Ion Gradients, Not ...
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What's inside the perinuclear space?

The cell proper contains the cytoplasm in general and the cytosol in particular when referring to the fluid/gel without notable organelle. Once we move inside the nucleus there is the nucleoplasm and ...
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Is the reason why lipid-soluble molecules can pass through membrane because [duplicate]

I have been studying about cell membranes and how water molecules are able to pass through it. (https://www.wiley.com/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm) It ...
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Why does carbon dioxide diffuse easier through the bilipid layer than oxygen?

When gas exchange occurs during respiration, the pressure of oxygen in alveoli is around 105 mmHg, whereas in the blood vessels in close contact with alveoli is 40 mmHg. For carbon dioxide the values ...
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Confused about definition of bulk flow of water by osmosis

As a teacher of high school and introductory college chemistry, I used textbooks that defined osmosis as a flow of water (only) through a membrane that prevents other substances such as dissolved ...
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Why does tetracycline have such a broad spectrum of activity?

What are the structural and chemical characteristics that make tetracycline uniquely broad spectrum? I understand it acts on the A-site of the prokaryotic ribosome, but there exist many ribosome-...

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