muscles

Skeletal muscles always work _____.

• in groups
• in pairs
• singly
• none of the above

A ______________________ attach bones to each other at joints.

• Ligament
• Bone
• Joint
• Cell

What is shown in the colored part of this diagram?

• a whole muscle

• five muscle fibers

• five muscle fascicles

• five myofibrils

What is labeled "4" (the blue/purple part) in the diagram?

• sarcolemma

• sarcoplasmic reticulum

• transverse tubules

• myofibril

Name the following in order from largest to smallest:

• muscle, muscle fascicle, muscle cell, myofibril, filaments

• muscle, muscle fascicle, muscle cell, filaments, myofibril

• muscle, muscle cell, muscle fascicle, myofibril, filaments

• muscle, muscle cell, muscle fascicle, filaments, myofibril

What is the length between Z-lines of an actin molecule called?

• fascicle

• sarcomere

• myosin binding site

• sarcoplasmic length

____________ attaches to actin to form the cross bridge.

• Troponin

• Tropomyosin

• Myosin

• Calcium

Which molecules bind to the actin molecule in a way that prevents a myosin head from forming a cross bridge?

• Myosin

• Actin

• Troponin-Tropomyosin

Which molecule supplies energy for the flexing of the myosin head "power stroke".

• calcium

• ATP

• sodium

Which molecule has a movable head that provides a power stroke when activated?

• Myosin

• Actin

• Troponin-Tropomyosin