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Question #45783

Difficulty: 8/10 | 🟢 Free

The Question

An in vitro experiment subjects human skeletal muscle myofilaments and a PCR mixture containing Thermus aquaticus DNA polymerase to a thermal shock of 85°C for 10 minutes. Upon returning both systems to their respective optimal working temperatures with abundant substrates (ATP, Ca2+, dNTPs), all of the following statements regarding their functional states are correct, EXCEPT:

Options

A.
The globular head of Heavy Meromyosin (HMM) will fail to hydrolyze ATP due to the irreversible disruption of its tertiary structure.
B.
Taq polymerase will maintain its structural integrity and continue to catalyze phosphodiester bond formation between dNTPs.
C.
The myofilaments will exhibit continuous ATP-dependent sliding because the thermal denaturation of troponin permanently unmasks F-actin active sites.
D.
The human muscle fibers will be unable to form new cross-bridges, regardless of intracellular Ca2+ levels, due to the loss of myosin's enzymatic activity.

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Comparative_Analysis

Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.

Concepts Behind This Question

Taq_Polymerase_Thermal_Stability|Myosin_ATPase|Heat_Shock_Proteins

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Students often analyze biological systems in isolation.

A student might correctly deduce that heat denatures the masking protein (troponin), leading them to falsely conclude that contraction will proceed unchecked (Option C).

However, they must synthesize the system as a whole: the effector protein (myosin ATPase) is simultaneously destroyed.

This question tests the understanding that muscle contraction is an interdependent process requiring BOTH the unmasking of actin AND a structurally intact, functional myosin ATPase.

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Locomotion and Movement - Class 11
Concept	Myofilament Protein Composition
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free