In this video we discuss the processes of hydrolysis and dehydration synthesis, and how these both use water. We also discuss how they are either catabolism or anabolism.



Hydrolysis and dehydration synthesis

Metabolism, or body chemistry is often used to generally describe all of the chemical reactions that occur in body cells. The two major types of metabolic activity that occur in the body are catabolism and anabolism.

Catabolism is the breaking down of complex molecules to form simpler ones and often times during the process, release energy. The release of energy is related to the disruption of chemical bonds. One of the important types of catabolic reactions is called hydrolysis.

Hydrolysis is the chemical breakdown of a compound due to reaction with water, so a water molecule is added to breakdown a larger molecule into smaller molecules or subunits. So, hydrolysis of sucrose, or table sugar, breaks the molecule into the smaller molecules of glucose and fructose.

Hydrolysis of protein breaks it down into smaller molecules of amino acids, and hydrolysis of a fat molecule breaks it down into its smaller subunits of glycerol and fatty acid molecules. Some of the energy released by catabolism is heat energy that keeps the body warm, and much of the energy released is transferred to a molecule called adenosine triphosphate or ATP.

Anabolism describes the many chemical reactions that take place to build larger, more complex molecules from smaller subunits. These reactions require energy, which often comes from the breakdown of atp, which was just mentioned.

One of the important types of anabolic reactions is called dehydration synthesis. In dehydration synthesis, water is removed as the larger molecules are formed. Anabolic reactions use energy to form larger carbohydrates, fats or lipids, and fuse amino acids together.

An example of this is when 2 amino acids join together to form what is called a peptide bond. A peptide bond is when the carboxyl or carbon, oxygen, hydrogen, hydrogen group of one amino acid bonds with the amino nitrogen, hydrogen, hydrogen group of another amino acid, as you can see here (on screen).

This is done through a dehydration synthesis reaction, as the amino group involved in the bond loses a hydrogen atom, and the carboxyl group involved in the bond loses an oxygen and hydrogen.

So, the peptide bonding results in the release of a water h2o molecule. More amino acids can link in, again releasing water molecules, and form what is called a polypeptide chain, which leads to the production of a protein molecule.

Timestamps
0:00 Metabolism and the 2 major types of metabolic activity in the body
0:16 What is catabolism in the body
0:28 What is hydrolysis
1:06 The energy released
1:19 What is anabolism in the body
1:35 What is dehydration synthesis