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Substances both enter and leave the cell by crossing the plasma membrane (outer membrane). They do this in one of the following ways.
Substances in solution tend naturally to spread until their concentration is uniform. Many substances enter and leave cells this way, because their concentration on one side of the plasma membrane is different from that on the other side.
A few substances cross the phospholipid bilayer, but their molecules have to be small and uncharged: oxygen, carbon dioxide, and water are examples.
The diffusion of other substances is facilitated by proteins. One family of such proteins is the channel proteins, which have a pore that allows substances to cross the membrane without interacting with the hydrophobic fatty acid chains of the phospholipids. The cell can open and close the pore. Channel proteins are not truly selective, but molecules must be small enough to pass through the pore, and must be suitably charged if the side-chains of the amino acids around the pore are charged.
Another family of membrane proteins that permit facilitated diffusion is the carrier proteins. These change conformation (shape) as a substance moves through them, and they are highly selective.
This is like "diffusion uphill", in that it involves substances being moved against (up) their concentration gradient. This cannot happen without an input of energy, which the cell provides, e.g by the hydrolysis of ATP.
The plasma membrane acts as a selectively permeable membrane (also known as a semi-permeable or differentially permeable membrane). Water crosses such a membrane if the total concentrations of solutes on either side of the membrane are different.
Water can cross the phospholipid bilayer by osmosis. However, some water also crosses through special proteins called aquaporins.
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In which process in which process this is so you molecules does the cell use a vesicles to move molecules into the cell?
cells
What is diffusion in cells?
diffusion- passive transport in cells where molecules move from an area where there are more molecules to an area of fewer molecules.
Is Diffusion made of small or large molecules?
Diffusion is not a substance. It is a physical process. Diffusion is the process where there is a movement of molecules from where they are abundant to where they are scarce. A more technical definition would be: Diffusion is a process in which molecules move from a region of higher concentration to a region of lower concentration.
Can hydrophilic molecules readily move unaided into and out of cells?
no
What is moving down the concentration gradient in all cells?
All small molecules can move down the concentration gradient as water O2, CO2 etc.
In which process in which process this is so you molecules does the cell use a vesicles to move molecules into the cell?
cells
What process does the cell use a vesicle to move molecules out of the cells?
Exocytosis is the process that moves molecules from the inside of the cell to the outside. This process uses sacs or vesicles to move the molecules out.
Is diffusion the main method by which small molecules move into and out of cells?
Yes.
In which process does a cell use a vesicle to move molecules into the cells?
Endocytosis (APEX)
Why molecules move into and out of cells?
Molecules move in and out of the cell by difffusion process and only those molecules which have size smaller then pore size of plasma membrane can move in and out of the cell. The second factor is ionic conc or is also known as conc gradient according to which molecules of required ionic status can move in and out of the cell
What is diffushion?
Diffusion is when small molecules move in and out of a cell. This process requires no energy aka passive transport!(:
What moves substances in and out of a cell?
Most molecules can move in and out of a cell, but different molecules have different methods of getting in- Small Non-Polar molecules can diffuse across the lipid bilayer Medium sized molecules of any kind require a specific protein channel HUGE MOLECULES require a process called endo and exocytosis
In which process dose the cell use a vesicle to move molecules out of the cell?
Exocytosis is the process that moves molecules from the inside of the cell to the outside. This process uses sacs or vesicles to move the molecules out.
What process does the cell use a vesicle to move molecules out of a cell?
Exocytosis is the process that moves molecules from the inside of the cell to the outside. This process uses sacs or vesicles to move the molecules out.
What process does a cell us a vesicle to move molecules out of a cell?
Exocytosis is the process that moves molecules from the inside of the cell to the outside. This process uses sacs or vesicles to move the molecules out.
What does pinocytosis move?
Pinocytosis is the process by which cells move fluid. It is a mode of endocytosis. It also brings in small particles to the cell.
What is diffusion in cells?
diffusion- passive transport in cells where molecules move from an area where there are more molecules to an area of fewer molecules.
