Question

How would muscle contractions be affected if ATP was completely depleted in a muscle fiber?

Short answer

Myosin heads will detach rapidly from the actinbinding sites, resulting in muscle relaxation.

Step-by-step solution

Step 1. Introduction

ATP Adenosine triphosphate is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis.

Step 2. Explanation 

If ATP was completely depleted in a muscle fiber then the muscle would relax and lengthen because ATP is required for myosin to release from actin, muscles would remain rigidly contracted until more ATP was available for the myosin cross-bridge release. This is why dead vertebrates undergo rigor mortis.