Question

What does it mean for the cell membrane to have a phospholipid bilayer?

The cell membrane contains one layer of fat


The cell membrane has two layers of phospholipids

Answer 1

The cell membrane's phospholipid bilayer consists of two layers of phospholipids, with hydrophobic tails facing inward and hydrophilic heads facing the aqueous environments inside and outside the cell. This structure allows the cell membrane to act as a selective barrier.

Step-by-step explanation:

When a cell membrane is described as having a phospholipid bilayer, it means that the membrane consists of two layers of phospholipids that are arranged tail to tail. Each phospholipid molecule features a hydrophilic (water-loving) polar head group and two hydrophobic (water-hating) fatty acid tails. The heads are oriented towards the water-rich environments inside and outside the cell, while the tails face each other, creating a hydrophobic interior that acts as a barrier to certain substances.

The cell membrane contains many different molecules, but phospholipids are the main component that provides the fluid structure needed for the cell. The presence of other molecules such as proteins, cholesterol, and carbohydrates, which are embedded within or attached to the phospholipid bilayer, give the membrane its unique properties and functions.

Answer 2

Phospholipid bilayers are critical components of cell membranes. The lipid bilayer acts as a barrier to the passage of molecules and ions into and out of the cell. However, an important function of the cell membrane is to allow selective passage of certain substances into and out of cells.