Question

why dna is difficult to pass through cell membrane. How bacterial cell is made component to enter cell membrane. Another way by which dna can enter

Answer 1

Dear student

DNA cannot pass through the cell membrane because it is a hydrophilic molecule. t is highly charged molecule. It is very difficult for a highly charged particle to passively diffuse across the cell membrane. The cell membrane is made up of phospholipids, cholesterol which makes DNA molecule impermeable to diffuse across the membrane.

Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42⁰C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA.

Competent cells are the bacterial cells which are ready to use for DNA technology. They have altered cell walls through which foreign DNA can be passed easily.
The method for making the bacteria competent is to suspend them in solution of high concentration of calcium ions. By this competency is achieved by creating pores in the bacterial cell wall.

Regards