Cell Membrane Structure and Function

Front

What is the primary function of the cell membrane?

Back

The cell membrane acts as a barrier to keep cell contents inside and facilitates the transport of specific molecules into or out of the cell.

Front

What is the cell membrane made of?

Back

The cell membrane is made up of a bilayer of phospholipid molecules.

Front

Describe the structure of a phospholipid molecule.

Back

Each phospholipid molecule has a hydrophilic head that faces the outside of the cell and a hydrophobic tail that faces the inside of the membrane.

Front

What is the role of the phospholipid bilayer?

Back

The phospholipid bilayer acts as a hydrophobic barrier, allowing non-polar substances to pass easily while polar substances cannot.

Front

What are integral proteins?

Back

Integral proteins penetrate the phospholipid bilayer and act as pumps in active transport or channels in facilitated diffusion.

Front

What are peripheral proteins?

Back

Peripheral proteins remain on the surface of the membrane

play a role in cell recognition

involved in immune response.

Front

What role does cholesterol play in the cell membrane?

Back

Cholesterol decreases the fluidity of the cell membrane

lowers its permeability to some molecules.

Front

What is the fluid mosaic model?

Back

The fluid mosaic model, developed by Singer and Nicolson in 1972, describes the cell membrane structure as a mosaic of proteins, carbohydrates, and lipids.

Front

What was the Davson-Danielli model?

Back

The Davson-Danielli model proposed a phospholipid bilayer with protein layers on both sides, but it was falsified as membrane proteins move freely within the membrane.