All of the following are plasma proteins found in blood, except one

Appeared in: UPPSC 2017

Explanation

Myosin is the correct answer as it is not a plasma protein.
It is a contractile protein that is a primary component of the thick filaments in muscle fibers.
The main function of myosin is to interact with actin to generate the force required for muscle contraction and movement.
It is located within muscle cells (myocytes) and does not circulate in the blood plasma under normal physiological conditions.

Option A: Albumin is the most abundant protein in blood plasma.
Option B: Globulins are a major group of plasma proteins, including antibodies (gamma globulins) essential for the immune system.
Option D: Fibrinogen is a crucial plasma protein synthesized in the liver that is converted to fibrin during blood coagulation.

Clinical Relevance

Nursing practice connection: Knowing Composition of blood plasma and identification of plasma proteins helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Measuring plasma protein levels is a common diagnostic practice. Low albumin levels (hypoalbuminemia) can suggest liver disease, kidney disease (nephrotic syndrome), or malnutrition, and often leads to edema.
Abnormal globulin levels can indicate immune disorders, infections, or certain cancers like multiple myeloma.
Fibrinogen levels are assessed to evaluate a patient's ability to form blood clots, which is critical before surgery or in cases of unexplained bleeding.

How to Approach the Question

First, identify the keyword 'except' in the question. This signals that you need to find the option that does not fit with the others.
Next, establish the common category for the options. The question specifies 'plasma proteins found in blood'.
Review each option to see if it fits the category. Is Albumin a plasma protein? Yes. Is Globulin a plasma protein? Yes. Is Fibrinogen a plasma protein? Yes.
Evaluate the final option. Is Myosin a plasma protein? No, it is a protein found in muscle cells.
Conclude that Myosin is the exception and therefore the correct answer.

Concept Tested & Keywords

Concept Tested: Composition of blood plasma and identification of plasma proteins.
Stem keywords: plasma proteins, blood
Lead-in keywords: except one
Negative lead-in flag: The question requires identifying the option that does not belong to the group of plasma proteins.

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E6 Harper's Illustrated Biochemistry2023 (pp 26-793 of 813) p. 619-621

E6 Physiology Guyton 4SAE Part 1 p. 168-170

E6 Biochemistry U Satyanarayana— Part 1 (pp 26-420 of 840) p. 180-182

Practise the full UPPSC 2017

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