Describe the difference between dehydration synthesis and hydrolysis. And give examples of macromolecules in which both types and reactions take place?
The correct answer and explanation is:
Dehydration synthesis and hydrolysis are two essential biochemical reactions that involve the addition or removal of water molecules to build or break down macromolecules.
Dehydration Synthesis (Condensation): This reaction occurs when two molecules combine to form a larger molecule, and a water molecule is released as a byproduct. It is used in the formation of complex macromolecules from smaller monomers. For example, when two amino acids join to form a dipeptide, a water molecule is released. Dehydration synthesis is a key process in the formation of various macromolecules like proteins, nucleic acids, and carbohydrates.
Example in Proteins: When two amino acids are linked by a peptide bond, a molecule of water is released in the process.
Hydrolysis: This is the opposite of dehydration synthesis. In hydrolysis, a water molecule is added to a larger molecule to break it down into smaller components. The water molecules “split” the bond between the monomers, and this reaction is crucial for digestion and the breakdown of complex molecules into simpler ones.
Example in Carbohydrates: When starch (a polysaccharide) is broken down into glucose molecules, water is added, breaking the glycosidic bonds between the sugar units.
Macromolecules Involved in Both Reactions:
- Proteins: During protein synthesis, dehydration synthesis links amino acids together into polypeptides, while hydrolysis helps break down proteins into individual amino acids during digestion.
- Carbohydrates: Polysaccharides like starch are formed via dehydration synthesis, where glucose molecules are linked together, and they are broken down into individual sugar units through hydrolysis.
- Nucleic Acids: In DNA and RNA, nucleotides are linked together by dehydration synthesis, forming the polynucleotide chain, and broken down by hydrolysis during processes like DNA replication and RNA degradation.
Both reactions are crucial for maintaining the structure and function of macromolecules, enabling the synthesis of new compounds or the breakdown of old ones, which is vital for cellular processes.