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Which substances are able to cross the membrane, and what determines their ability to do so?
Certain substances, such as small molecules and ions, are able to cross the cell membrane. The ability of a substance to cross the membrane is determined by its size, charge, and solubility in the lipid bilayer of the membrane.
Can small polar molecules cross the cell membrane?
Yes, small polar molecules can cross the cell membrane through a process called passive diffusion.
How do polar molecules cross the cell membrane?
Polar molecules cross the cell membrane through a process called facilitated diffusion, where they move with the help of specific transport proteins embedded in the membrane. These proteins create channels or carriers that allow polar molecules to pass through the hydrophobic interior of the membrane.
Why is a cell membrane called semi-permeable or selectively permeable?
As the cell membrane only allows certain substances to enter or leave the cell, meaning that while it IS permeable (as some substances can cross it), it is only selectively as not all substances are able to cross it, only some.
Is an ability of a plasma membrane to allow some substance to cross across the membrane more easily than others?
Yes, the ability of a plasma membrane to allow some substances to cross more easily than others is called selective permeability. This is due to the presence of specific transport proteins and channels that facilitate the movement of certain molecules while restricting others. The lipid bilayer of the membrane also plays a role in regulating which substances can pass through.
Which substances are able to cross the membrane, and what determines their ability to do so?
Certain substances, such as small molecules and ions, are able to cross the cell membrane. The ability of a substance to cross the membrane is determined by its size, charge, and solubility in the lipid bilayer of the membrane.
Can small polar molecules cross the cell membrane?
Yes, small polar molecules can cross the cell membrane through a process called passive diffusion.
What is the function (job) of lipids?
That is just another name for the cell membrane. It's main job is to keep the things that are on the inside of a cell inside, and keep what things are outside the cell on the outside. It is also called a semipermeable membrane because it can allow some things, under certain situations, to cross the phospholipid bilayer to enter or exit the cell.The phsopholipid bilayer is the thin polar cell membrane comprised of two layers of lipids. This membrane surrounds a cell to keep substances (ions, proteins, etc) in or out of the cell, but also allow selected substances to pass through the cell membrane as required.
How membrane is selectively permeable?
means that the cell membrane has some control over what can cross it, so that only certain molecules either enter or leave the cell
What does a cell membrane have that makes it easier for certain molecules to cross the cell membrane?
Cell membranes have proteins like channel proteins and carrier proteins that facilitate the transport of certain molecules across the membrane. These proteins provide specific pathways for molecules to pass through, making it easier for them to cross the membrane. Additionally, some molecules can cross the membrane through simple diffusion if they are small and non-polar.
What is a thin sheet of materials that selectively aloows certain molecules to cross but prevents others from crossing?
Semi-permeable membrane
The proccess by which a protein channel allows molecules to cross the cell membrane is called?
Facilitated diffusion
What can move across the plasma membrane freely by diffusion without the help of a transmembrane protein?
Water and small, non-polar molecules can cross the membrane without transport proteins. The process of this automatic movement is called diffusion; the diffusion of water specifically is called osmosis.
How do polar molecules cross the cell membrane?
Polar molecules cross the cell membrane through a process called facilitated diffusion, where they move with the help of specific transport proteins embedded in the membrane. These proteins create channels or carriers that allow polar molecules to pass through the hydrophobic interior of the membrane.
What needs to get into the cell and cross the cell membrane?
Oh things like food, oxygen, ions, and even hormones.
Why is a cell membrane called semi-permeable or selectively permeable?
As the cell membrane only allows certain substances to enter or leave the cell, meaning that while it IS permeable (as some substances can cross it), it is only selectively as not all substances are able to cross it, only some.
What does the term selectively permable mean?
"Selectively permeable" refers to a membrane that allows certain substances to pass through while blocking others. This selectivity is based on the size, charge, or other properties of the molecules trying to cross the membrane. An example is a cell membrane, which permits the passage of specific molecules necessary for the cell's function while blocking others.
