Problem 55 - Objective Biology for NEET

Question

Thyroid controls the metabolism of (a) Carbohydrates (b) Proteins (c) Lipids (fat) (d) All of these

Step-by-Step Solution

Answer

(d) All of these

Step 1: Understanding the function of the thyroid gland

The thyroid gland is an endocrine organ located in the neck. It produces and releases thyroid hormones into the bloodstream. These hormones play crucial roles in the body's metabolism, which includes processes like growth and energy production. These hormones, namely thyroxine and triiodothyronine, affect almost every cell in the body.

Step 2: Identifying the types of metabolism

The metabolism of carbohydrates, proteins, and fats (lipids) are all key biological processes within the body. Carbohydrate metabolism is the whole of the biochemical processes responsible for the metabolic formation, breakdown, and interconversion of carbohydrates in living organisms. Protein metabolism denotes the various biochemical processes responsible for the synthesis of proteins and amino acids, and the breakdown of proteins by catabolism. Lipid metabolism is the synthesis and degradation of lipids in cells, involving the breakdown or storage of fats for energy.

Step 3: Making the connection

The thyroid hormones increase the metabolism of carbohydrates, proteins, and fats. Therefore, the thyroid indirectly helps to control the metabolic rate of all these molecules.

Key Concepts

Metabolism

Metabolism is the entirety of life-sustaining chemical reactions in organisms. It is crucial for maintaining life and encompasses all processes for generating energy and building blocks for cells. There are two main aspects of metabolism:

• Catabolism - The breakdown of molecules to obtain energy.
• Anabolism - The synthesis of all compounds needed by the cells.

These reactions convert the chemical energy found in food into mechanical energy and heat. Carbohydrates, proteins, and lipids all undergo metabolic processes:

• Carbohydrate metabolism involves the breakdown of glucose, which is the body's primary energy source.
• Protein metabolism covers the utilization of amino acids for energy or building proteins.
• Lipid metabolism deals with the breaking down or storing of fats.

Understanding these processes is essential because they regulate body mass, energy supply, and even the function of other organs.

Endocrine System

The endocrine system is a network of glands that produce and secrete hormones necessary for body regulation. These hormones are chemical messengers that travel through the bloodstream to target organs and tissues. The system includes various glands such as:

• Thyroid gland
• Adrenal glands
• Pancreas
• Pituitary gland

Each of these glands has specific functions and secretes particular hormones. For example: - The thyroid gland secretes thyroid hormones that regulate metabolism. - The adrenal glands produce cortisol and adrenaline for stress response. - The pancreas produces insulin to regulate blood sugar levels.
The coordination of these hormones helps maintain homeostasis, affecting growth, metabolism, and reproduction. A healthy endocrine system is vital for proper development and overall well-being.

Thyroid Hormones

Thyroid hormones are essential to regulating metabolism, growth, and development. The two primary thyroid hormones, thyroxine (T4) and triiodothyronine (T3), have broad effects throughout the body. Here's how they function:

• Thyroxine (T4) - Produced in larger amounts but less active; it is converted into T3 in various tissues.
• Triiodothyronine (T3) - More potent, playing a pivotal role in regulating body temperature, metabolism, and heart rate.

Thyroid hormones work on almost every cell, influencing: - Energy metabolism, by increasing the basal metabolic rate, thereby promoting the use of carbohydrates, lipids, and proteins for energy. - Growth and maturation, especially in children, they help in the development of the brain and physical growth.
Maintaining proper levels of these hormones is essential for normal body function. Imbalances can lead to conditions such as hypothyroidism or hyperthyroidism, which respectively involve an underactive or an overactive thyroid gland.