In found in the cel membrane as a blyer lipids protein nucleic ocid carbohydrate

## Step 1<br />The cell membrane, also known as the plasma membrane, is a biological membrane that separates the interior of all cells from the outside environment. It is selectively permeable, meaning it allows certain substances to pass through while blocking others.<br /><br />## Step 2<br />The cell membrane is primarily composed of a lipid bilayer, which is a two-layered structure of lipids. These lipids are arranged in such a way that their hydrophobic (water-repelling) tails point inward, away from the water, while their hydrophilic (water-attracting) heads point outward, towards the water.<br /><br />## Step 3<br />The lipid bilayer acts as a barrier, protecting the cell from its surroundings and regulating the substances that enter and leave the cell. This is why lipids are found in the cell membrane as a barrier.