Problem 125 - Objective Biology for NEET

Question

How \(\mathrm{O}_{2}\) and \(\mathrm{CO}_{2}\) gets transported through blood? (a) With the help of RBCs and blood plasma (b) With the help of RBCs and WBCs (c) With the help of WBCs and blood serum (d) With the help of platelets and corpuscles

Step-by-Step Solution

Answer

The transportation of \(\mathrm{O}_{2}\) and \(\mathrm{CO}_{2}\) in blood is accomplished with the help of Red Blood Cells (RBCs) and blood plasma.

Step 1: Understanding the Blood Components

Red Blood Cells (RBCs) are responsible for transporting oxygen from the lungs to all of the body's tissues, and then bringing carbon dioxide from those tissues back to the lungs. White Blood Cells (WBCs) function mainly as part of the immune system and do not participate in gas transport. Plasma is the liquid component of the blood which also aids in the transportation of gases. Blood serum is plasma without clotting factors and does not play a role in gas exchange. Platelets are involved in clotting and do not transport gases. Corpuscles can refer to RBCs, WBCs, or platelets, depending on the context.

Step 2: Matching Components with Functions

Based on the functions of the blood components, it is clear that RBCs play a major role in transporting oxygen and carbon dioxide. Plasma, by carrying dissolved oxygen and carbon dioxide, also plays a significant role.

Step 3: Choosing the Correct Answer

Since RBCs and plasma are the two key components involved in the transport of oxygen and carbon dioxide in the blood, the correct answer is (a) With the help of RBCs and blood plasma.

Key Concepts

Red Blood Cells (RBCs)

Red Blood Cells, often abbreviated as RBCs, play a vital role in gas transport in our bodies. These small, biconcave cells are packed with a special protein called hemoglobin. Hemoglobin is crucial because it binds to oxygen in the lungs and carries it throughout the body. Once these oxygen-laden RBCs reach body tissues, they release the oxygen, which helps cells perform their various functions.
RBCs then pick up carbon dioxide, a waste product from cellular activities, to transport it back to the lungs for exhalation.

• Oxygen binds to hemoglobin in RBCs.
• RBCs transport oxygen to body tissues.
• Carbon dioxide is picked up by RBCs and brought back to the lungs.

This ability of RBCs to transport both oxygen and carbon dioxide efficiently makes them indispensable in maintaining the body's gas balance.

Blood Plasma

Blood plasma is the light yellow liquid portion of blood that serves many important functions, one of which is gas transport. Plasma is composed mainly of water, about 90%, and contains dissolved gases like oxygen and carbon dioxide.
While RBCs carry the majority of oxygen bound to hemoglobin, a small proportion is dissolved directly in the plasma itself. Similarly, carbon dioxide is not only carried by RBCs but is also dissolved in the blood plasma for transportation back to the lungs.

• Plasma consists of water, proteins, and dissolved gases.
• Dissolved oxygen in plasma complements RBC transport.
• Dissolved carbon dioxide aids in regulating blood pH.

The roles of blood plasma in transporting dissolved gases are subtle yet essential for adequately managing our body's gas requirements.

Carbon Dioxide Transport

The transport of carbon dioxide through blood is a fascinating process that involves multiple pathways. Carbon dioxide, a product of cellular respiration, is transferred from cells into the bloodstream in three primary ways:

• Approximately 70% is converted into bicarbonate ions through a reaction catalyzed by an enzyme called carbonic anhydrase. This occurs inside RBCs.
• About 20-25% of carbon dioxide is bound to hemoglobin in RBCs, forming a compound known as carbaminohemoglobin.
• A small fraction, roughly 5-10%, is dissolved directly in the blood plasma.

This multi-faceted transport mechanism ensures CO₂ is swiftly removed from tissues and delivered to the lungs for expiration. It's a crucial aspect of maintaining the acid-base balance in the body, highlighting the critical symbiosis between different blood components.