30 Questions
What is the function of the Z disks in a myofibril?
Hold the myosin filaments in place
What is the main role of the myosin molecule heads in muscle contraction?
Bind to active sites of action molecules forming cross-bridges
What is the function of the A bands in a sarcomere?
Extend the length of the myosin filament
Which component of the myosin molecule releases energy through ATP breakdown?
Myosin heads
What is the purpose of the I bands in a sarcomere?
Extend from Z disks to ends of myosin filaments
How do Z disks contribute to muscle contraction?
Hold the actin filaments in place
What is the term used to describe muscles that work together in a group to cause a movement?
Synergists
In the context of muscle movements, what is the role of fixator muscles?
To stabilize joints
Which muscle is described as the prime mover when flexing the elbow according to the text?
Brachialis
What is the main role of an antagonist muscle in a muscle group?
To oppose the action of the prime mover
In muscle movements, what is a lever defined as, based on the laws of physics?
A rigid shaft for transferring force
When performing finger extension, what is the function of fixator muscles like flexor carpi radialis and flexor carpi ulnaris?
To stabilize the wrist
Which muscle functions to flex the hip?
Iliacus
What is the common site for injections by doctors in the hip region?
Gluteus maximus
Which muscle is used for propulsion from a sprinter's stance?
Gluteus maximus
Which muscle is not categorized as one of the thigh muscles discussed in the text?
Gluteus minimus
Which category do the posterolateral hip muscles belong to?
Anterior hip muscles
What is the function of the deep hip muscles mentioned in the text?
Rotation of the thigh
Which muscle primarily functions to move the forearm?
Biceps brachii
Which muscle is not involved in shoulder abduction?
Pectoralis major
What muscle extends the elbow?
Triceps brachii
Which muscle is responsible for lateral rotation of the arm?
Infraspinatus
What muscle holds the head of the humerus?
Coracobrachialis
Which muscle is involved in both flexion and extension of the shoulder?
Deltoid
What is a troponin molecule composed of?
One sub-unit that binds to calcium ions, another that binds to actin, and a third that binds to tropomyosin
What is the structure of the myosin myofilament?
An elongated golf club-like shape with heavy and light myosin chains
What is the primary function of the G-actin monomers in F-actin polymer?
Provide an active site for myosin binding
How are the heads of myosin molecules positioned within a myosin myofilament?
Alternating directions on each end of the filament
What is the main role of tropomyosin in the actin myofilament?
Coils around the F-actin strands and provides structure
Which component of the troponin molecule binds specifically to calcium ions?
Sub-unit that binds to calcium ions
Test your knowledge on the structure of actin myofilaments, including the composition of F-actin, tropomyosin, and troponin. Understand how F-actin forms a double helix structure and its polymerization with G-actin monomers.
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