how cell membrain becomes selectively permeable?

Answer 1

Cell membranes are made of these molecules called phospholipids, with proteins, carbohydrates, and steroids mixed in. Phospholipids have two parts: a head and a tail. The head is a phosphate and hydrophilic (likes water). The tail is a lipid and hydrophobic (hates water). Like begets like, so these molecules naturally line up in a double layer, with the phosphate heads on the outside, and the lipid tails on the inside.

It is selective because of the hydrophobic tails of the bilayer. Water is the only thing that can go through the layer without any help or energy required. The proteins that are scattered throughout the membrane facilitate the entry and exit of molecules through the layer.

Answer 2

Cell Membrane is selectively permeable because it allows only certain substance to pass throught with the help of membrane proteins. Water is the one that can easily cross the membrane.
Hence Cell membrane is also called as semi permeable membrane.

Answer 3

There are lots of distinctive spells that artwork for turning out to be a mermaid, right it is the single i understand superb: a million) Get a Pisces flower. that's a particular style of flower, with seven almond shaped petals that are sea-green. you will desire to have the means to discover it below water, a pair of quarter of a mile from shore. once you have it, wreck it into pulp and combine that pulp with sparkling sea water. circulate away out interior the completed moon's shine in one day. 2) consume that combination, and close your eyes. do no longer OPEN THEM. 3) walk to the sea, nevertheless which contain your eyes closed. on the way, repeat this mermaid chant: Iv A Von, Sartis, Menamon, Sartis. Iv A Von, Menamon, Jagsta, Kestar, Sartis. Iv A Von, Sartis, Menamon, Sartis. Iv A Von, Venamon, Casta, Mex. 4) once you sense your get touching the sea water, keep on going until you're thoroughly submerged. Open your eyes. despite you do, do no longer resurface until your sight darkens thoroughly. Your legs will sense numb and you will sense drained, yet do no longer hassle, it is the technique of turning right into a mermaid. once you awaken, nicely. you will see. ;)