A dehydration reaction (or condensation reaction) is the process in which ___
A water molecules are used as a source of raw material to break down polymers to monomers
B water molecules are attracted to each other the bonds between
C the individual monomers of a polymer are broken by the addition of water molecules
D water molecules are produced as a polymer is formed from monomers
E None of the choices is correct.
The correct answer and explanation is :
The correct answer is:
D) Water molecules are produced as a polymer is formed from monomers.
Explanation:
A dehydration reaction, also known as a condensation reaction, is a chemical process in which monomers (small molecules) combine to form a polymer (a larger molecule) by removing a water molecule. This reaction is essential for the synthesis of macromolecules such as proteins, carbohydrates, and nucleic acids.
How It Works:
During a dehydration reaction, two monomers are joined together by a covalent bond. In the process, a hydroxyl group (-OH) is removed from one monomer, while a hydrogen atom (-H) is removed from the other monomer. These two removed components combine to form a molecule of water (H₂O), which is then released as a byproduct.
For example, in the formation of a disaccharide (a type of carbohydrate), two monosaccharides (simple sugars) undergo a dehydration reaction:
[
\text{Monosaccharide}_1 + \text{Monosaccharide}_2 \rightarrow \text{Disaccharide} + H_2O
]
A similar process occurs in protein synthesis, where amino acids are linked by peptide bonds through dehydration reactions. Likewise, nucleotides are joined to form nucleic acids (DNA and RNA) by the removal of water molecules.
Why Is It Important?
- Biological Macromolecule Formation: Dehydration reactions are fundamental in building essential biological macromolecules such as proteins, polysaccharides, and nucleic acids.
- Energy Storage & Function: The polymers formed (e.g., glycogen, starch, proteins) serve as structural materials and energy storage compounds in living organisms.
- Reversibility: The reverse process, called hydrolysis, breaks down polymers into monomers by adding water, which is crucial for digestion and metabolism.
Thus, dehydration reactions play a key role in life by enabling the synthesis of complex molecules necessary for cellular function.