Question

The correct statement about protein haemoglobin is that it (a) maintains blood sugar level (b) acts as an oxygen carrier in the blood (c) functions as a catalyst for biological reactions (d) forms antibodies and offers resistance to diseases

Short answer

The correct statement is (b): acts as an oxygen carrier in the blood.

Step-by-step solution

Understanding the Role of Hemoglobin

Hemoglobin is a protein found in red blood cells. It's important to understand what its specific role is within the body to correctly answer the question.

Analyzing Option (a)

The statement 'maintains blood sugar level' is incorrect. Hemoglobin does not regulate blood sugar levels; that’s the role of insulin.

Analyzing Option (b)

The statement 'acts as an oxygen carrier in the blood' is correct. Hemoglobin binds to oxygen in the lungs and transports it to tissues throughout the body.

Analyzing Option (c)

The statement 'functions as a catalyst for biological reactions' is incorrect. Enzymes catalyze reactions, not hemoglobin.

Analyzing Option (d)

The statement 'forms antibodies and offers resistance to diseases' is incorrect. The immune system, not hemoglobin, produces antibodies to combat diseases.

Key concepts

Hemoglobin's Role

Hemoglobin is an essential protein located within our red blood cells. Its primary function is to transport oxygen from the lungs to other parts of the body. This role is vital because every cell requires oxygen to function properly. Hemoglobin achieves this by binding to oxygen molecules inhaled into the lungs. Once bound, it carries the oxygen through the bloodstream, delivering it efficiently to various tissues and organs.

• Hemoglobin is made up of four protein subunits, each capable of binding to an oxygen molecule.
• With its iron-rich structure, hemoglobin provides the means for oxygen to latch onto the red blood cells.
• Once it delivers the oxygen, hemoglobin then carries carbon dioxide, a waste product, back to the lungs for exhalation.

Oxygen Transport

Oxygen transport is a critical function in maintaining healthy body systems. Through the efficient workings of hemoglobin, our bodies can ensure that oxygen reaches each cell to facilitate essential processes.
When you inhale, oxygen enters your lungs and reaches the alveoli, where it meets blood in capillaries. Hemoglobin molecules in the red blood cells capture this oxygen through the alveolar wall.

• The oxygen-rich blood is then sent from the lungs to the heart and pumped throughout the body's circulatory system.
• Cells use this oxygen in the mitochondria to produce energy, a process known as cellular respiration.
• Deoxygenated blood, now containing carbon dioxide, returns to the lungs to complete the cycle.

Red Blood Cells

Red blood cells, or erythrocytes, are crucial for transporting oxygen throughout the body. These cells are primarily responsible for housing hemoglobin, and they have a unique structure to support this function.
Red blood cells are biconcave in shape, which increases their surface area, allowing for more efficient oxygen absorption and release.

• The lack of a nucleus in red blood cells allows more space for hemoglobin and therefore more oxygen transport capacity.
• These cells have a short lifespan, typically around 120 days, and are constantly being replenished by the body.
• The production of red blood cells occurs in the bone marrow, and hormones like erythropoietin regulate their production based on the body's oxygen needs.

Enzyme Function

Enzymes are proteins that significantly speed up the rate of chemical reactions in the body, without being consumed by the reaction. They are essential for sustaining life, helping processes like digestion, metabolism, and DNA replication occur at a viable rate.
Unlike hemoglobin, enzymes act as catalysts. This means a small amount of an enzyme can prompt the transformation of reactant molecules into products rapidly and repeatedly.

• Each enzyme is specific to a particular reaction or type of reaction.
• They work by lowering the activation energy needed for a reaction to occur, making biochemical reactions occur faster.
• Enzymes are also highly regulated within the body to ensure that reactions occur only when and where they are needed.

Immune System

The immune system protects the body against infections, diseases, and foreign substances. It is not involved in oxygen transport or blood sugar regulation, but rather in identifying and neutralizing pathogens like bacteria, viruses, and other harmful organisms.
This amazing defense mechanism relies on a complex network of cells and proteins:

• White blood cells, or leukocytes, play a crucial role by identifying and combating pathogens.
• Antibodies, which are proteins made by the immune system, specifically recognize and bind to antigens on the surface of pathogens.
• The immune response often involves both the innate (immediate) and adaptive (specialized) branches working together to protect the body.
• This system also has a memory, allowing for a quicker response upon subsequent encounters with the same pathogen.