Problem 62 - Objective Biology for NEET

Question

Thymosin is (a) Peptide hormone (b) Secreted by pituitary (c) Helps in RBC production (d) Decreases WBC production

Step-by-Step Solution

Answer

The correct answer is (a): Thymosin is a peptide hormone.

Step 1: Identifying the Hormone Type

Thymosin is indeed a peptide hormone. Peptide hormones are composed of short chains of amino acids. Let's proceed to the next option.

Step 2: Identifying the Secretion Gland

Thymosin is not secreted by the pituitary gland. It is secreted by the thymus gland, therefore, option (b) is incorrect.

Step 3: Understanding Its Function in RBC Production

Thymosin does not help in Red Blood Cell (RBC) production, but it plays an important role in the development and function of the immune system, especially in the production of T lymphocytes. Thus, option (c) is incorrect.

Step 4: Assessing Its Influence on WBC Production

Thymosin does not decrease White Blood Cell (WBC) production. On the contrary, it plays a crucial role in the maturation of T cells, a type of WBC, leading to an increase in their production. Hence, option (d) is also incorrect.

Key Concepts

Peptide hormone

Thymosin is categorized as a peptide hormone. Peptide hormones are composed of chains of amino acids linked together. They can vary greatly in length and composition, from short chains to complex structures. These hormones are water-soluble, making them easily transportable through the bloodstream to target tissues. Once they reach their target, peptide hormones bind to receptors on the surfaces of cells, initiating a range of responses inside the cell. This process is crucial for regulating numerous bodily functions, such as metabolism, growth, and immune system responses. The peptide nature of thymosin means it plays specific roles in biochemical pathways, ensuring the proper functioning of the body's immune responses.

Thymus gland

The thymus gland is a small organ located in the upper chest, beneath the breastbone. It plays a vital role in the body's immune system, particularly during early life. The thymus is responsible for producing thymosin, along with other important molecules necessary for immune system maturation. Its primary function is to support the development and differentiation of T lymphocytes, which are critical to the immune response. As a person ages, the thymus gradually decreases in size and becomes less active, reflecting a shift in immune system reliance from production to maintenance of lymphocyte populations.

T lymphocytes

T lymphocytes, or T cells, are a type of white blood cell crucial for adaptive immunity. These cells originate from hematopoietic stem cells in the bone marrow but mature in the thymus gland. Thymosin plays an important role in this maturation process, helping transform immature cells into fully functional T cells. Once matured, T lymphocytes can identify and attack infected cells, providing a targeted immune response against pathogens. They can also remember these pathogens for faster responses in future encounters, showcasing their importance in immunological memory and defense mechanisms.

Immune system

The immune system is our body's defense network against infections and diseases. It consists of various organs, cells, and proteins working in harmony to recognize and neutralize harmful invaders. A strong immune system relies on the proper function and production of immune cells, including T lymphocytes. Thymosin and the thymus gland are pivotal in maintaining this balance, ensuring that T cells effectively combat pathogens. The cells communicate using signals to orchestrate attacks on invaders and to remember past infections for quicker response. This dynamic system keeps us healthy by preventing and fighting infections efficiently.