The protein found in blood that is responsible for transporting oxygen is?

Appeared in: DHS 2018 shift 1st

Explanation

Hemoglobin is the red pigment protein found exclusively in red blood cells (erythrocytes).
Its primary biological function is the delivery of oxygen (O₂) from the lungs to the tissues.
Hemoglobin contains a non-protein part called heme, which has an iron atom at its center. This iron atom is where oxygen reversibly binds.
Each hemoglobin molecule is a tetramer, meaning it has four subunits, and can therefore bind and transport up to four molecules of oxygen.

Option A: Erythropoietin is a hormone that stimulates red blood cell production (erythropoiesis), but it does not bind to or transport oxygen itself.
Option C: Gamma globulins are antibodies (immunoglobulins) and are key components of the adaptive immune system. Their function is to identify and neutralize pathogens, not transport gases.
Option D: This option is incorrect because only one of the listed substances, hemoglobin, is responsible for oxygen transport. Erythropoietin and gamma globulins have different, distinct functions.

Clinical Relevance

Nursing practice connection: Knowing Function of Blood Proteins helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Measuring hemoglobin levels is a fundamental part of a complete blood count (CBC). Low hemoglobin indicates anemia, leading to symptoms like fatigue and shortness of breath due to poor oxygen delivery.
In carbon monoxide (CO) poisoning, CO binds to hemoglobin with an affinity over 200 times greater than oxygen, forming carboxyhemoglobin. This prevents oxygen transport and can be fatal.
The level of glycated hemoglobin (HbA1c), where glucose binds to hemoglobin, is a crucial marker for monitoring long-term blood sugar control in patients with diabetes mellitus.

How to Approach the Question

First, identify the key terms in the question: 'protein', 'blood', and 'transporting oxygen'.
The core of the question is to identify the specific protein that carries oxygen.
Evaluate each option based on your knowledge of blood components.
Recall that Hemoglobin is the well-known oxygen-carrying molecule in red blood cells.
Consider the function of Erythropoietin (stimulates RBC production) and Gamma globulin (immunity).
Eliminate the incorrect options. Since Erythropoietin and Gamma globulin do not transport oxygen, 'All of the above' is also incorrect, leaving Hemoglobin as the only correct choice.

Concept Tested & Keywords

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E6 Biochemistry U Satyanarayana— Part 1 (pp 26-420 of 840) p. 190-192

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 15-17

Practise the full DHS 2018 shift 1st

Attempt every question from this paper in a timed mock, then review the full solution for each one.