Question

The muscle you can see on the microscope screen was stained for myosin ATPase and a darker stain indicates a higher capacity to use ATP. This means muscles can contract more quickly and can be considered fast twitch. Which of the three cells on the microscope screen can be considered fast twitch?

a) 1
b) 2 and 3
c) 1, 2, and 3
d) 1 and 2

Answer 1

Muscle cells that are stained darker for myosin ATPase, indicating a higher capacity to use ATP and faster contraction, can be considered fast twitch. Therefore, the correct answer is b) 2 and 3.

Step-by-step explanation:

Fast-twitch muscle fibers are characterized by a higher capacity for quick contraction and are well-suited for activities that require strength and speed. Myosin ATPase staining is commonly used to distinguish between fast and slow-twitch muscle fibers. In the given microscope screen, the cells that appear darker after staining for myosin ATPase are indicative of a higher ATPase activity, signifying fast-twitch characteristics.

Cell 1 does not exhibit a darker stain, suggesting a lower ATPase activity and, consequently, a slower twitch. On the other hand, cells 2 and 3 show a darker stain, indicating a higher ATPase activity and faster contraction, making them fast-twitch muscles. Therefore, the correct choice is b) 2 and 3.

Understanding the staining patterns of muscle cells provides valuable insights into their functional properties and helps researchers and physiologists categorize and study different types of muscle fibers based on their contractile characteristics.

Correct option is b) 2 and 3.