what is phospholipid bilayer and what is its significance?

Answer 1

It is what makes up the cell membrane. The phospholipids have hydrophyllic heads and hydrophobic tails. There are also proteins that are associated with it. The bilayer and the proteins maintain homeostasis in the cell by controlling what enters and leaves.

Answer 2

Without it we would just be a pool of goo...

The phospholipid is polar on the phosphate side, and hydrophobic (non-polar) on the lipid side. This causes the lipid tails to point together while the phosphate groups point outward.

This bilayer separates the inside of the cell from the outside of the cell.

Molecules cannot get through unless they are very small lipid soluble molecules.

The membrane has proteins that allow the molecules that the cell needs to move in and out to do this (selectively permeable).

Without the membrane, the cell would not exist, and neither would we...

Answer 3

The phospholipid bilayer is the cell (plasma) membrane. It is composed of two layers of phospholipid molecules. Phospholipids are polar fats. This means that one end of the molecule attracts water (hydrophylic) while the other end of the molecule repels water (hydrophobic). In the cell membrane these molecules are arranged so that the hydrophylic ends point outward (one layer) and inward (the second layer) while the hydrophobic tails point inward. This gives the cell its ability to be semipermeable (selectively permeable). Only substances that are lipid (non-polar) soluable can pass through the bilipid layer. Other molecules and ions must use other means of entering or leaving the cells (membrane-bound globular proteins that act as channels, gates, carrier molecules) or endo- or exocytosis.

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