Question

Lipids are insoluble in water because lipid molecules are _________

• A. Hydrophilic
• B. Hydrophobic
• C. Neutral
• D. Zwitter ions

Answer 1

The correct option is B

Hydrophobic

The correct option is B

Explanation of the correct option:

1. Lipids are chemical substances that are nonpolar in nature.
2. Because water is a polar molecule, they are only soluble in nonpolar solvents and insoluble in water.
3. These molecules can be produced in the human body and are found in oil, butter, whole milk, cheese, fried meals, and some red meats.
4. Carbon atom bonds and those between carbon and hydrogen molecules in lipids are nonpolar, whereas electrons shared in the bond between oxygen and hydrogen atoms in a water molecule are not equally shared, resulting in the formation of a slight positive charge on hydrogen and a slight negative charge on the oxygen atom.
5. The presence of hydrogen bonding also affects solubility because the presence or absence of hydrogen bonding has a large cumulative effect on the physical properties of a molecule.

Explanation of the incorrect option:

Option A:

Molecules such as proteins, nucleic acids, and carbohydrates have an affinity for water and are called hydrophilic.

Option C:

Lipid molecules are hydrophobic and not neutral.

Option D:

Lipids cannot be Zwitter ions.

Final answer: Lipids are insoluble in water because lipid molecules are hydrophobic.