Question

Which of the following is correct about a muscle contraction?

ATP causes fascicles to contract muscle fibers.


Myofibrils attach to Z lines.


Myosin heads attach to sites on actin filaments.

Sarcomeres produce actin and myosin.

Answer 1

Which of the following is correct about a muscle contraction? A.Sarcomeres produce actin and myosin.
B.(Correct Response) Myosin heads attach to sites on actin filaments. C.Myofibrils attach to Z lines. D. ATP causes fascicles to contract muscle fibers.

Which structure is composed of the filaments actin and myosin?
A.fascicle
B.(Correct Response) myofibril
C.muscle fiber
D.sarcomere


Which statement is correct about how muscles move bones? A. The origin is where only flexors attach to move a nearby bone.
B. Extensors cause a bone to move initially. C. Tendons connect extensors and flexors to each other.
D. (Correct Answer) The insertion is where a muscle attaches to the bone it wants to move.

Answer 2

The correct answer would be "Myosin heads attach to sites on actin filaments".

The muscle cell or myofibril consists of two types of protein filaments namely; actin (thin filament) and myosin (thick filament).

The myosin heads attach to the binding sites on the actin filaments and pull it towards the M-line in order to produce contraction.

The hydrolysis of ATP provides energy for this contraction cycle.