Question

How is the plasma membrane of a cell organized?

Question 15 options:

one layer of phospholipids, through which proteins freely move

one layer of phospholipids, which are laid out end-to-end, with a hydrophobic tail touching a hydrophilic head

two layers of phospholipids, each of which has its hydrophilic side turned inward

two layers of phospholipids, with their polar hydrophilic heads facing away from each other

Answer 1

The plasma membrane is organized into a phospholipid bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward, providing a barrier for the cell. It also includes proteins such as integral proteins that help transport molecules.

Step-by-step explanation:

The plasma membrane of a cell is organized into a phospholipid bilayer, where each phospholipid molecule consists of a hydrophilic head that is attracted to water, and two hydrophobic tails that repel water. The hydrophilic heads face outward, towards the cell's watery environment and the cell's internal cytoplasm, while the hydrophobic tails face inward, away from the water, creating a hydrophobic interior region. This arrangement provides a barrier that separates the interior of the cell from the external environment.

In the bilayer, the phospholipids are arranged tail to tail, with their hydrophobic tails associating with one another in the interior of the membrane and the polar hydrophilic heads contacting the aqueous fluid both inside and outside the cell. The membrane is also interspersed with various types of proteins, such as integral proteins which can form channels for specific molecules to pass through.

Answer 2

The correct answer is two layers of phospholipids,with their polar hydrophilic heads facing away from each other.

Step-by-step explanation:

The plasma membrane of a cell contain lipid bilayer.Each monolayer contain phospholipids.The hydrophobic tails of the phospholipid of both the monolayers faces each other in the hydrophobic region where as the hydrophilic heads of the phospholipid molecules of both the monolayers are oriented away from each other.