Na+ ions are able to move against a concentration gradient across the cell membrane by a process called "active transport" which requires the expenditure of energy, such energy being provided by the utilization of ATP. Adenosine triphosphate is the most important "energy currency" of the cell.
This active transport is carried out by carrier proteins, which are embedded in the phospholipid bilayer of the plasma membrane. Na+ ions are moved against their concentration gradient by carrier proteins called sodium pumps.The same thing happens with K- (Potassium) ions and that's why it's called the cell's Na+/K-pump.
Sodium is a positively-charged ion (a cation) and so cannot diffuse directly through the hydrophobic interior of the cell membrane.
There are two ways Na+ ions can cross the membrane:
1) by facilitated diffusion: there are proteins which provide a channel to allow Na+ ions to diffuse through the membrane; these channel proteins are passive and only allow Na+ to diffuse down its concentration gradient
2) by active transport: most cells have a protein pump in the membrane which actively pumps Na+ out of the cell; this uses energy from ATP which is made in the cell by respiration, and so can pump ions against their concentration gradient
They are actively transported with sodium-potassium pumps. Two potassium ions are pumped for every three sodium ions.
is an active transport by a pump because in order to go from a low to a high concentration we need energy.
It gets a mini taxi, pays the driver 50 bucks, then walks for 30 min. and runs a spear through it.
Through diffusion.
Water Movement across a cell membrane is called Osmosis. And it is dependent on the concentration of ions on each side of the cell membrane. If the concentration is higher on the inside of the cell water rushes in to dilute the ion concentration and get it to equal the outside concentration of ions and this is called hypotonic. If the concentration is higher outside the cell water will rush out of the cell to help dilute the concentration outside the cell and get the two concentrations to become equal and is called hypertonic. If the concentration is equal in both outside and inside the cell there will be no water movement and is called isotonic. Osmosis
The inside of cells have a higher concentration of Potassium. But there's a higher concentration of Sodium outside the cell.
The phenomenon that describes the movement of any kind of molecule from areas of higher concentration to areas of lower concentration is called diffusion.
Active transport
Movement of molecules 4m higher to lower concentration is called osmosis
active transport
Any ion that is positive but has a higher concentration inside the cell or is negative and has a higher concentration outside the cell. Any ion that is positive but has a higher concentration inside the cell or is negative and has a higher concentration outside the cell.
Osmosis is the movement of water form its higher concentration to lower concentration through a semi permeable membrane. In it water can move from inside to outside or outside to inside.
Diffusion
Water Movement across a cell membrane is called Osmosis. And it is dependent on the concentration of ions on each side of the cell membrane. If the concentration is higher on the inside of the cell water rushes in to dilute the ion concentration and get it to equal the outside concentration of ions and this is called hypotonic. If the concentration is higher outside the cell water will rush out of the cell to help dilute the concentration outside the cell and get the two concentrations to become equal and is called hypertonic. If the concentration is equal in both outside and inside the cell there will be no water movement and is called isotonic. Osmosis
osmosis is the passive movement of a substance from a place where its concentration is higher, to another where its concentration is lower. This applies to gases, I guess
Osmosis the the movement of water from where it is higher concentration to where it is in lower concentration.
diffusion is the kinetic movement of molecules from higher concentration to lower concentration.
The inside of cells have a higher concentration of Potassium. But there's a higher concentration of Sodium outside the cell.
higher concentration to a area of lower concentration
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration. Osmosis is the diffusion of water molecules (only) from an area of higher concentration to an area of low concentration.
If placed in a hypertonic solution, cells will shrink because the solute concentration outside the cell will be higher than inside the cell. This causes the movement of water out of the cell (in order to equalise the concentration).