In ultracentrifugation, which statement is true about the creamy layer?

In ultracentrifugation, which statement is true about the creamy layer?

• A. The creamy layer is HDL
• B. The creamy layer is LDL
• C. The creamy layer is chylomicrons
• D. The creamy layer is VLDL

Answer: (C)

In ultracentrifugation, lipoproteins separate by density, so the least dense particles rise to the very top. Chylomicrons are the largest and most triglyceride-rich, giving them the lowest density (below about 0.95 g/mL). Because of this, they float to the cream-colored top layer when plasma is spun at high speeds. The denser particles—VLDL, LDL, and HDL—remain below in progressively denser layers. So the top creamy layer, formed by those lowest-density particles, is the chylomicrons.

In ultracentrifugation, lipoproteins separate by density, so the least dense particles rise to the very top. Chylomicrons are the largest and most triglyceride-rich, giving them the lowest density (below about 0.95 g/mL). Because of this, they float to the cream-colored top layer when plasma is spun at high speeds. The denser particles—VLDL, LDL, and HDL—remain below in progressively denser layers. So the top creamy layer, formed by those lowest-density particles, is the chylomicrons.