Polar head group

Definition

The polar head group is the hydrophilic part of a lipid molecule that interacts with water and other polar substances. It typically contains phosphate, glycerol, or another polar group.

5 Must Know Facts For Your Next Test

1. Polar head groups are crucial for the formation of lipid bilayers in cell membranes.
2. They interact with aqueous environments inside and outside of cells.
3. Common components of polar head groups include phosphates and charged functional groups.
4. Their hydrophilicity contrasts with the hydrophobic tails of lipids, aiding in membrane stability.
5. The composition of the polar head group can affect membrane fluidity and function.

Review Questions

• What role do polar head groups play in the structure of cell membranes?
• Identify common components found in polar head groups.
• How does the polarity of the head group influence its interaction with water?

Related terms

Hydrophobic Tail: The part of a lipid molecule that repels water and interacts with other nonpolar substances.

Lipid Bilayer: A double-layered structure formed by lipids in aqueous environments, fundamental to cell membranes.

Phospholipid: A type of lipid containing a phosphate group as part of its polar head, essential for forming cell membranes.