Question

question 8
1 pts
as a muscle contracts, which of the following things happens?
the muscle creates energy.
the z disks move closer together.
the sarcomeres extend.
the myofibrils break down.

Explanation:

According to the sliding - filament theory of muscle contraction:

• Energy is not created by the muscle; it uses pre - existing energy sources like ATP.
• During contraction, the Z - disks (which mark the boundaries of sarcomeres) move closer together as the thin filaments (actin) slide over the thick filaments (myosin) within the sarcomeres. Sarcomeres shorten, not extend.
• Myofibrils do not break down during normal muscle contraction.

Answer:

The Z disks move closer together.