Question

How does the movement of substances take place in the cell?? How do substances move out of the cell??

Answer 1

Cell membrane:

1. The plasma membrane or cell membrane is a lipid bilayer membrane in which proteins are embedded that separate the cytoplasm of the cell from the extracellular spaces.
   
2. It is selectively permeable that regulates the transportation of molecules.
3. The transportation of molecules across the membrane can be active or passive.

Active transport:

1. Active transport is the movement of molecules (ions, glucose, and amino acids) across the membrane against the concentration gradient.
   
2. It requires cellular energy in the form of ATP.
   
3. The protein molecules embedded within the membrane act as channels through which molecules can pass.
   
4. These proteins are called carriers i.e, the molecule attaches to the carrier protein which then transports that molecule into the cell.

Passive transport:

1. Passive transport is the movement of molecular substances across cell membranes along the concentration gradient without any energy.
   
2. They are of three types:-
3. Diffusion is the movement of molecules from the area highly concentrated to an area where the molecules are less concentrated.
4. Osmosis is the diffusion of water molecules.
5. Filtration is the movement of water and solute molecules across the cell membrane due to hydrostatic pressure generated by the cardiovascular system.