#1
Which molecule is directly responsible for providing energy to muscles during contraction?
Adenosine triphosphate (ATP)
ExplanationATP is the energy currency of cells, providing energy for muscle contraction.
#2
Which of the following muscle types is striated and under voluntary control?
Skeletal muscle
ExplanationSkeletal muscles are striated and under conscious control.
#3
Which structure connects muscle to bone, allowing for movement to occur at a joint?
Tendon
ExplanationTendons connect muscles to bones, facilitating movement at joints.
#4
Which protein serves as the main structural component of thin filaments in muscle fibers?
Actin
ExplanationActin is the main structural component of thin filaments in muscle fibers, playing a central role in muscle contraction.
#5
Which term refers to the ability of a muscle to respond to a stimulus?
Excitability
ExplanationExcitability is the ability of a muscle to respond to a stimulus, such as a nerve impulse.
#6
What is the term used to describe the ability of a muscle to return to its original length after being stretched?
Elasticity
ExplanationElasticity refers to a muscle's ability to return to its original length after being stretched.
#7
Which neurotransmitter is released at the neuromuscular junction to stimulate muscle contraction?
Acetylcholine
ExplanationAcetylcholine is the neurotransmitter responsible for initiating muscle contraction at the neuromuscular junction.
#8
Which term describes the smallest functional unit of a muscle fiber?
Sarcomere
ExplanationSarcomere is the basic unit of muscle contraction, containing overlapping actin and myosin filaments.
#9
What is the primary function of the sarcoplasmic reticulum in muscle cells?
Storage and release of calcium ions
ExplanationThe sarcoplasmic reticulum stores and releases calcium ions, which are crucial for muscle contraction.
#10
Which type of muscle contraction occurs when the force generated by the muscle is greater than the resistance, resulting in shortening of the muscle?
Concentric contraction
ExplanationConcentric contraction involves muscle shortening as it generates more force than the resistance.
#11
During muscle contraction, which protein binds to calcium ions to expose active sites on actin filaments?
Troponin
ExplanationTroponin binds to calcium ions, facilitating the interaction between actin and myosin during muscle contraction.
#12
Which hormone stimulates muscle growth and protein synthesis in response to resistance training?
Growth hormone
ExplanationGrowth hormone promotes muscle growth and protein synthesis, especially in response to resistance training.
#13
Which regulatory protein blocks the myosin-binding sites on actin in a relaxed muscle?
Tropomyosin
ExplanationTropomyosin blocks myosin-binding sites on actin in relaxed muscles, preventing contraction.