In fast-twitch oxidative-glycolytic fibers, their rapid increases in force rely on the activity where rapid relaxation requires activity.

1. myosin ATPase

2. Ca2+-ATPase

Explanation:

ATPase activity of myosin head hydrolysis ATP and energize the myosin head. The energized myosin head forms cross bridges to facilitate the power stroke of muscle contraction. The fast-twitch oxidative-glycolytic fibers have the ability to produce ATP by aerobic respiration.  

These fibers have the  ATPase in their myosin heads that hydrolyze ATP three to five times faster than the myosin ATPase in slow fibers. This ensures the faster speed of contraction of these fast-twitch muscle fibers.

During their relaxation, Ca2+ ATPase pumps the calcium ions back to the sarcoplasmic reticulum. As the level of Ca2+ ions in the sarcoplasm decreases, calcium ions are released from troponin. Tropomyosin is allowed to cover the myosin-binding sites on actin and the muscle fiber relaxes faster.

hi my name is ashlynn and im 15

these macromolecules could either be amino acids, proteins or nucleic acids. they are responsible for the chemical changes and reactions that affects largely the cell and its composition. take for instance the cytoplasm of the cell where these organelles are settled. these simple organelles are composed of macromolecules which ignites and catalyses different functions that enables cells, in macro-perspective in motion and metabolism. in intestines for example, metabolism happens and breaking down parts of a food to simpler compounds that are used and these nutrients delivered throughout the body and again broken down by into smaller components.