Question

Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure. Explain these classes and give one factor that distinguishes each.

a) Lipid-soluble hormones, peptide hormones, and steroid hormones; each class has varying half-lives.
b) Protein hormones, peptide hormones, and steroid hormones; each class acts through different signaling pathways.
c) Protein hormones, peptide hormones, and steroid hormones; each class has different receptor locations.
d) Water-soluble hormones, lipid-soluble hormones, and steroid hormones; each class varies in their site of synthesis.

Answer 1

Hormones in the human body are divided into lipid-derived, amino acid-derived, and peptide hormones based on their chemical structure, with solubility and receptor location being the distinguishing factors between them.

Step-by-step explanation:

There are many different hormones in the human body, and they can be divided into three classes based on their chemical structure:

• Lipid-derived hormones (or Lipid-soluble hormones) - These hormones are non-polar and can diffuse across cell membranes. Most lipid-derived hormones are made from cholesterol and include steroids such as estrogen and testosterone. They are insoluble in water and typically have receptors located within the cytoplasm or nucleus of their target cells.
• Amino acid-derived hormones - These are relatively small molecules derived from amino acids like tyrosine and tryptophan. Examples include epinephrine and melatonin. They are generally water-soluble and their receptors are located on the surface of target cells.
• Peptide hormones - Composed of chains of amino acids, these hormones are water-soluble and cannot pass through the plasma membrane of cells. Therefore, their receptors are found on the external surface of the target cells. Examples include oxytocin and growth hormone.

The main factor that distinguishes these classes is their solubility and receptor location. Lipid-soluble hormones diffuse across membranes due to their non-polar nature and interact with intracellular receptors, while amino acid-derived and peptide hormones are not able to cross the cellular membrane and thus bind to extracellular receptors.