While active transportrequires energy and work, passive transportdoes not. There are several different types of this easy movement of molecules. It could be as simple as molecules moving freely such as osmosis or diffusion. You may also see proteins in the cell membrane that act as channels to help the movement along. And of course there is an in-between transport process where very small molecules are able to cross asemi-permeable membrane.
Answer:
i am not sure but probaby d
Explanation:
Hdl has a high proportion of protein, which makes it the heaviest (most dense) lipoprotein.
The five main subgroups of lipoproteins include high-density lipoprotein (HDL). All fat molecules (lipids) are transported throughout the body by lipoproteins, complex particles made of several proteins that float outside of cells and move throughout the body's fluids.
Through both direct and indirect channels, HDL mostly delivers cholesterol to the liver or to organs that can produce steroid hormones, such as the testicles, ovary, and adrenal glands.
Scavenger receptor BI (SR-BI), an HDL receptor that facilitates the selective uptake of cholesterol from HDL, is one type of HDL receptor that removes HDL. The indirect pathway, which is mediated by the cholesteryl ester transfer protein, is likely the most significant one in humans (CETP).
Following conversion into bile acids, the cholesterol supplied to the liver is either directly or indirectly excreted into the bile and, consequently, the intestine.
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