Concept explainers
Polar molecules
- a. dissolve in lipids.
- b. are hydrophobic.
- c. contain covalent bonds.
- d. contain ionic bonds.
Introduction: Molecules having ionized groups and polar bonds get readily dissolved in water and they are called as hydrophilic or “water loving molecules”. The presence of polar groups such as hydroxyl groups and carboxyl and amino groups promotes the solubility of molecules in water.
Answer to Problem 1MC
Correct answer: Option c. “contain covalent bonds”.
Explanation of Solution
Reason for the correct answer:
Option c. is given as “contain covalent bonds”.
A covalent bond is a type of chemical bond that is formed when there is sharing of one or more than one pair of electrons (valence) between atoms. It is of two types, namely polar covalent bond and nonpolar covalent bond. Polar covalent bonds result from the unequal distribution of shared electrons, as they are slightly closer to more electronegative atoms. The molecules that form such bonds are known as polar molecules.
Hence, option c. is correct.
Reasons for the incorrect answers:
Option a. is given as “dissolve in lipids”.
The polar molecules cannot dissolve in lipids, due to the nonpolar nature of the lipids.
Hence, option a. in incorrect.
Option b. is given as “are hydrophobic”.
Polar molecules are hydrophilic in nature.
Hence, option b. is incorrect.
Option d. is given as “contain ionic bonds”.
The ionic bonds are formed when the sharing of electrons between two atoms are unequal, while the covalent bonds are formed when the two atoms are able to share their electrons.
Hence, option d. is incorrect.
Hence, options a., b., and d. are incorrect.
Covalent bonds are present in polar molecules.
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Chapter 3 Solutions
Pearson eText Biology: Life on Earth with Physiology -- Instant Access (Pearson+)
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