Answer:
The correct statement about phospholipids is:
3. Tails of phospholipids are hydrophobic.
The other statements are incorrect:
1. Heads of phospholipids are hydrophobic: This statement is incorrect. The heads of phospholipids are hydrophilic, meaning they have an affinity for water. The hydrophilic head contains a phosphate group, which is attracted to water molecules.
2. Phospholipids allow any particle to freely pass through the phospholipid bilayer: This statement is incorrect. The phospholipid bilayer acts as a selective barrier that controls the movement of molecules in and out of the cell. While small, non-polar molecules like oxygen and carbon dioxide can freely diffuse through the lipid bilayer, larger molecules or polar molecules (such as ions or water) require specialized proteins called transporters or channels to move across the membrane.
4. Phospholipids do not allow small particles to freely pass through the phospholipid bilayer: This statement is incorrect. Small, non-polar molecules like oxygen and carbon dioxide can freely diffuse through the lipid bilayer. It is the larger molecules or polar molecules that require specialized proteins for transport.
In summary, the tails of phospholipids are hydrophobic, while the heads are hydrophilic. This unique property allows phospholipids to arrange themselves in a bilayer formation called the phospholipid bilayer, which forms the basis of cell membranes. The hydrophobic nature of the tails creates a barrier that restricts the free movement of certain molecules, while allowing others to pass through.
Step-by-step explanation:
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