The amino acid Tryptophan is the precursor for the synthesis of :
- Thyroxine and Triiodothyronine
- Estrogen and Progesterone
- Cortisol and Cortisone
- Melatonin and Serotonin
The Correct Option is D
Solution and Explanation
Correct Answer: Option 4 – Melatonin and Serotonin
Explanation:
Tryptophan is an essential amino acid that serves as a biochemical precursor for several important biomolecules:
- Serotonin – a neurotransmitter important for mood regulation, sleep, and appetite, is synthesized directly from tryptophan.
- Melatonin – a hormone involved in regulating the sleep-wake cycle (circadian rhythm), is synthesized from serotonin, and hence indirectly from tryptophan.
The biosynthetic pathway is:
\(Tryptophan \rightarrow 5-HTP \rightarrow Serotonin \rightarrow Melatonin\)
Therefore, tryptophan is the precursor for both serotonin and melatonin.
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Concepts Used:
Proteins
An essential part of every cell in our body, protein is one of the three macronutrients which is required by our body in larger amounts. Proteins are made up of linear chains of smaller units called amino acids. Every biochemical process that takes place inside our bodies is possible because of these proteins. Proteins are 3-dimensional structures that are assembled with different amino acid sequences.
Functions of Protein
Proteins are used in many ways. Some of their functions are:
- Enzymes: Most of the important chemical reactions which take place inside a cell are mostly carried out by enzymes. They also play a role in regenerating and creating DNA molecules and carrying out complex processes.
- Hormonal Regulation: Proteins create various types of hormones that help in balancing the components of the body. For example, hormones like insulin help in regulating blood sugar and secretin. The formation of digestive juices essential for the whole digestion process is also possible because of hormones.
- Protection: Being the main constituent of antibodies, proteins protect our body against antigens and pathogens thus preventing infections.
- Energy: Proteins are one the most essential sources of energy required for our body movements. The right amount of proteins should be consumed so that they can be turned into energy.
- Structural functions: Proteins are the building blocks of the body. They are required for the growth, development, healing, and repair of tissues. Proteins are essential in order to strengthen various structures like hair, skin, and muscles. It is also present in the outer membrane of all cells in the human body.
Classification of Protein
Proteins are classified on the basis of:
- Shape
- Constitution
- Nature of Molecules
Protein Structure
A protein molecule is made from a long chain of amino acids, each linked to its neighbor through a covalent peptide bond. The structure of proteins are divided into four types:
- Primary Structure
- Secondary Structure
- Tertiary Sector
- Quaternary Structure