Question

What metabolites cause muscle fatigue?

A) Adenosine triphosphate.
B) Adenosine diphosphate and adenosine monophosphate.
C) Adenosine triphosphate and adenosine monophosphate.
D) Mg2+ and adenosine triphosphate.
E) Sarcoplasmic reticulum and mitochondria.

Answer 1

Muscle fatigue is primarily caused by the accumulation of ADP and AMP, which are produced when ATP is used up during muscle contraction, and by the buildup of lactic acid affecting muscle pH.

Step-by-step explanation:

The metabolites that cause muscle fatigue are the by-products of ATP hydrolysis, specifically Adenosine Diphosphate (ADP) and Adenosine Monophosphate (AMP). ATP (Adenosine Triphosphate) is the primary energy currency of the cell, especially for muscle contraction.

During intense exercise, ATP is rapidly used up and breaks down into ADP and AMP. These latter molecules can indicate a lowered energy state within the muscle, contributing to fatigue as the muscle's ability to contract diminishes. Furthermore, the accumulation of lactic acid resulting from anaerobic glycolysis can also lead to fatigue, as it decreases the pH within muscle cells, affecting enzymes function.