0
Why are membrane more permeable to non-polar molecules than to most polar and ionized molecules?
Wiki User
∙ 14y ago
Because the permeation through a membrane depends on the diffusivity (size of the permeate molecules) and the solubility (briefly the interaction equilibrium) of the permeate in the membrane. Considering permeate mixtures, membranes can be size-selective and sorption-selective depending on which relative term (ratio of diffusivities or ratio of solubilities) dominates. Most known membrane separation processes involve size-selectivity, i.e., the "smaller" the permeate molecule, the faster it gets through the membrane. More sophisticated membrane separation processes are sorption selective, where it is possible that the "bigger" molecules exhibit a higher permeation flux than the "smaller" ones.
Wiki User
∙ 14y ago
Membranes are composed of a phospholipid bilayer which has a hydrophobic core. Non-polar molecules can easily pass through this hydrophobic region via simple diffusion. In contrast, polar and ionized molecules face difficulty passing through due to their interactions with the hydrophilic head groups of the phospholipids.
Wiki User
∙ 11y agoit's simply because the lipid bi layer is nonpolar, and like substances dissolve other like substances. polar molecules don't interact with non-polar and that is why the cell membrane does not allow polar molecules to diffuse right through.
Wiki User
∙ 14y agob/c the cell membrane is made out of phospholipids! thus lipis diffuse readily
Wiki User
∙ 12y agoBecause the membranes are made up of phospholipid bilayers
Wiki User
∙ 14y agoNon-polar molecules are generally smaller than polar and ionized ones. The non-polar tails of the phospholipids repel ionic molecules and don't allow them to pass.
Wiki User
∙ 14y agoBecause the phospholipids of the plasma membrane are lipid, and a lipid soluable such as cholesterols can pass through the membrane.
Wiki User
∙ 11y agoparce que c'est dommage
Add your answer:
Earn +20 pts
Are ionized molecules less reactive than non-ionized molecules?
Ionized molecules are generally more reactive than non-ionized molecules because they have unpaired electrons or a charge that makes them more likely to participate in chemical reactions. This increased reactivity is due to the higher energy state of ionized molecules compared to non-ionized ones.
Are Ions charged atoms or groups of atoms?
Either one. You can have an ionized atom or an ionized molecule. Many ionized molecules are radicals that had been part of a larger molecule and the event that separated them also ionized the radical. This is what free radicalsare.
The fraction of acetic acid molecules ionized in solution?
The fraction of acetic acid molecules ionized in solution can be calculated using the equation for the dissociation constant (Ka) of acetic acid. It is equivalent to the concentration of the ionized form (CH3COO-) divided by the total concentration of acetic acid in the solution. This is typically a small percentage for weak acids like acetic acid.
Why do mole drug molecules have both water-soluble and oil-soluble functional groups?
The drug has to be water soluble to dissolve as gastrointestinal fluid is aqueous. The drug also has to be oil soluble as only the lipid soluble non-ionized form can readily diffuse across the lipid membrane.
Does a gas remain ionized forever?
No, a gas does not remain ionized forever. The ions in a gas can recombine with electrons to form neutral atoms or molecules. The time it takes for a gas to recombine depends on the specific conditions such as temperature and pressure.
What molecules can pass phospholipid bilayer?
Non ionized molecule pass through the lipid bilayer faster than ionized molecules because of the hydrophobic portion of the lipid bilayer. non ionized molecules are ex glucose ionized molecute Na, K
Are ionized molecules less reactive than non-ionized molecules?
Ionized molecules are generally more reactive than non-ionized molecules because they have unpaired electrons or a charge that makes them more likely to participate in chemical reactions. This increased reactivity is due to the higher energy state of ionized molecules compared to non-ionized ones.
Do water molecules ionize when they freeze?
No, the ice molecules in ice are not ionized.
Are Ions charged atoms or groups of atoms?
Either one. You can have an ionized atom or an ionized molecule. Many ionized molecules are radicals that had been part of a larger molecule and the event that separated them also ionized the radical. This is what free radicalsare.
How would you build a model that is ionized?
When the number of electrons does not equal the number of protons, the atom is ionized. (The atom is then called an ion).
Is a distilled water a polar or nonpolar?
Ionized water means that there are ions in a solution of water. Water itself, whether alone or floating with ions, will always be polar. Other ions or molecules don't affect water's polarity without changing the compound, in which case it will no longer be water.
The fraction of acetic acid molecules ionized in solution?
The fraction of acetic acid molecules ionized in solution can be calculated using the equation for the dissociation constant (Ka) of acetic acid. It is equivalent to the concentration of the ionized form (CH3COO-) divided by the total concentration of acetic acid in the solution. This is typically a small percentage for weak acids like acetic acid.
What is an autoionization?
An autoion is an ion which has been formed via the process of autoionization - where atoms or molecules spontaneously transition from an electrically neutral state to a lower-energy ionized state.
Why do mole drug molecules have both water-soluble and oil-soluble functional groups?
The drug has to be water soluble to dissolve as gastrointestinal fluid is aqueous. The drug also has to be oil soluble as only the lipid soluble non-ionized form can readily diffuse across the lipid membrane.
Why are drugs in solid form unlikely to be absorbed in the stomach to any significant extent?
Only the lipid soluble non-ionized form of a drug can diffuse across the membrane. The pH is low in the stomach. For the acidic drugs, they are non-ionized at low pH yet they are poorly soluble. For the basic drugs, they are soluble yet ionized.
What substance can pass through the lipid bilayer i.e. in between the phospholipid molecules?
Non-polar molecules, small polar molecules, and gases like oxygen and carbon dioxide can pass through the lipid bilayer passively due to its semi-permeable nature. These molecules can easily diffuse through the hydrophobic core of the membrane.
Is alkaline ionized water healthy?
Yes alkaline ionized water is one of the best substances you can put into your body. The process of ionizing water changes the way water molecules cluster, typically water has 15 to 25 molecules per cluster, when passed through a water ionizer the clusters usually contain 6 to 10 molecules. This enables your body to absorb more water.
