Lipoproteins are special molecules that help transport lipids (fats) through the bloodstream.
Since lipids do not dissolve in water, they cannot travel freely in blood. So, the body combines them with proteins to form lipoproteins, which can move easily in the watery blood.
Structure:
A lipoprotein has:
- An outer layer made of proteins and phospholipids (water-friendly).
- An inner core containing triglycerides and cholesterol (fat-friendly).
This structure lets lipids travel safely through the blood.
Functions of Lipoproteins:
- Transport Fats:
Carry triglycerides and cholesterol to and from different parts of the body. - Energy Supply:
Deliver fatty acids to tissues for energy use. - Cell Membrane Formation:
Provide cholesterol and phospholipids for making cell membranes.
Main Types of Lipoproteins:
- HDL (High-Density Lipoprotein): “Good cholesterol”; carries fat away from tissues to the liver for removal.
- LDL (Low-Density Lipoprotein): “Bad cholesterol”; carries fat to tissues, can build up in arteries.
- VLDL (Very Low-Density Lipoprotein): Transports triglycerides from the liver to tissues.
- Chylomicrons: Carry fats from the digestive system to the bloodstream.
In short:
Lipoproteins act as carriers of fat in the blood, helping transport cholesterol and triglycerides throughout the body for energy, storage, or removal.