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How would a polar molecule like water travel through the plasma membrane?
The structure of cell membrane allows nonpolar molecules to diffuse, but not polar molecules. Membrane architecture is in the form of a phospholipid bilayer. A single phospholipid has a "head" composed of a polar NH3 group, and two "tails" composed of nonpolar fatty acids. The lipids spontaneously arrange themselves into bilayers with the hydrophilic heads directed outward, and the hydrophobic tails facing inward. Because nonpolar solvents can only dissolve nonpolar solutes, polar molecules cannot mix with the nonpolar inside of the lipid bilayer. A polar molecule cannot cross the cell's lipid membrane without aid from a carrier protein. While this is true, there are multiple forces that dictate whether or not a molecule can cross a phospholipid membrane, including electrochemical gradients and size. Very small and non-polar molecules have a very easy time crossing the phospholipid bilayer. However, very small, polar molecules like water can also cross the phospholipid bilayer due to hydrostatic pressure and concentration gradient differences. Water will, but with some difficulty because of it's polarity. Aquaporins, protein channels embedded into cellular membranes allow for sufficient amounts of water to diffuse into cells.
When phospholipid molecules are mixed with water they form small balloon structures called?
Liposomes
What can pass through the bilayer with ease?
Molecules that are not polar or ion molecules. That is because they won't be stopped by the hydrophobic tails and they will have the acknowledgement to pass through the cell membrane thanks to little resistance. This makes those molecules have an advantage.
How does eukaryotic and prokaryotic organisms undergo facilitated diffusion?
Diffusion is the ability of molecules to follow a concentration gradient, moving from regions of high to low concentration. For small, nonpolar molecules such as O2, CO2, and some narcotics, they are small enough to slip through the phospholipid bilayer of the plasma membrane. Small, polar molecules such as water, are also small enough to slip through, but because of their polar nature, this movement is impeded by a factor of 1000. What about larger molecules like glucose? These molecules are too big to slip through the phospholipid bilayer, regardless of the concentration gradient. Larger molecules require a protein channel for transport across the plasma membrane. Because the movement will be driven by the concentration gradient, this movement is called facilitated diffusion, to indicate that a protein channel is necessary. Both prokaryotic and eukaryotic cells have protein channels for this purpose.
What kind of things can pass through the phospholipid bilayer?
Lipid-soluble molecules, such as oxygen, carbon dioxide, and steroid hormones, readily diffuse through plasma membranes. Water, however, requires small pores called aquaporins therefore it is aided.
Why are fat soluble molecules the only molecules that permeate across a cell membrane?
Because small non polar molecules are the ones able to cross due to the fact that the membrane consists of a phospholipid bilayer where the middle is composed on non polar tails
How would a polar molecule like water travel through the plasma membrane?
The structure of cell membrane allows nonpolar molecules to diffuse, but not polar molecules. Membrane architecture is in the form of a phospholipid bilayer. A single phospholipid has a "head" composed of a polar NH3 group, and two "tails" composed of nonpolar fatty acids. The lipids spontaneously arrange themselves into bilayers with the hydrophilic heads directed outward, and the hydrophobic tails facing inward. Because nonpolar solvents can only dissolve nonpolar solutes, polar molecules cannot mix with the nonpolar inside of the lipid bilayer. A polar molecule cannot cross the cell's lipid membrane without aid from a carrier protein. While this is true, there are multiple forces that dictate whether or not a molecule can cross a phospholipid membrane, including electrochemical gradients and size. Very small and non-polar molecules have a very easy time crossing the phospholipid bilayer. However, very small, polar molecules like water can also cross the phospholipid bilayer due to hydrostatic pressure and concentration gradient differences. Water will, but with some difficulty because of it's polarity. Aquaporins, protein channels embedded into cellular membranes allow for sufficient amounts of water to diffuse into cells.
Why do some materials diffused through the mimbrean while others don't?
the membrane may only allow small particles or may only allow polar/nonpolar molecules, hydrophobic vs hydrophyllic molecules
When phospholipid molecules are mixed with water they form small balloon structures called?
Liposomes
What is a phospholipid bilayer and where would you find it?
Phospholipids are polymers made up of two fatty acids, glycerol, a phosphate group and a polar molecule. A cell's membrane consists phospholipids where they form two layers (with the polar molecules facing opposite ends) to separate the interior of the cell from the outside environment. This is called a phospholipid bilayer.
What can pass through the bilayer with ease?
Molecules that are not polar or ion molecules. That is because they won't be stopped by the hydrophobic tails and they will have the acknowledgement to pass through the cell membrane thanks to little resistance. This makes those molecules have an advantage.
What types of materials can enter the cell?
small molecules through the integral proteins in the phospholipid bilayer
What does Phospholipid Bilayer?
The phospholipid bilayer is the outer layer of the cell. It only lets very small molecules through it. The bigger ones will have to go through the proteins lodged in the bilayer and the HUGE molecules will have to perform exocytosis or endocytosis
How does eukaryotic and prokaryotic organisms undergo facilitated diffusion?
Diffusion is the ability of molecules to follow a concentration gradient, moving from regions of high to low concentration. For small, nonpolar molecules such as O2, CO2, and some narcotics, they are small enough to slip through the phospholipid bilayer of the plasma membrane. Small, polar molecules such as water, are also small enough to slip through, but because of their polar nature, this movement is impeded by a factor of 1000. What about larger molecules like glucose? These molecules are too big to slip through the phospholipid bilayer, regardless of the concentration gradient. Larger molecules require a protein channel for transport across the plasma membrane. Because the movement will be driven by the concentration gradient, this movement is called facilitated diffusion, to indicate that a protein channel is necessary. Both prokaryotic and eukaryotic cells have protein channels for this purpose.
What kind of things can pass through the phospholipid bilayer?
Lipid-soluble molecules, such as oxygen, carbon dioxide, and steroid hormones, readily diffuse through plasma membranes. Water, however, requires small pores called aquaporins therefore it is aided.
How is membrane structure related to the transport of materials?
Membrane is thin and Êsemi permeable to allow Êmaterials to enter and exit easily. In addition, it Êconsist Êof protein Êand phospholipid bilayer, Êprotein layer release ÊproteinÊÊmolecules which act as carriers across the membrane.Ê Whereas, phospholipid bilayer Êallow small molecules such as water molecules to pass through quicker.
Describe how the diffusion of ions across a cell membrane differs from the diffusion of nonpolar molecules across the cell membrane?
Ions need to be facilitated through a cell membrane because they are passing through a phospholipid bilayer with a hydrophobic interior. Non polar molecules are also hydrophobic, so they can pass through the membrane easily if they are small enough. Ions are polar, so they have a hard time passing through membranes.
