Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
Muscle can transform ______ into mechanical energy.
A. ATP
ATP (adenosine triphosphate) is the primary energy currency of the cell. Muscle cells use ATP to power the contraction process, converting chemical energy into mechanical energy through the interaction of actin and myosin filaments.
B. Kinetic energy
Kinetic energy is the result of movement, not the source of energy for muscle contraction. Muscles generate kinetic energy, but they do not transform it into mechanical energy.
C. Potential energy
Potential energy refers to stored energy, such as in a stretched elastic band. While muscles can store potential energy in elastic components, the transformation into mechanical energy is driven by ATP.
D. DNA
DNA carries genetic information and plays no direct role in energy transformation during muscle contraction.
E. Myoglobin
Myoglobin stores oxygen in muscle cells but does not provide energy. It supports aerobic metabolism, which ultimately produces ATP, the actual energy source.
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Full Explanation
Choice A reason: ATP (adenosine triphosphate) is the primary energy currency of the cell. Muscle cells use ATP to power the contraction process, converting chemical energy into mechanical energy through the interaction of actin and myosin filaments.
Choice B reason: Kinetic energy is the result of movement, not the source of energy for muscle contraction. Muscles generate kinetic energy, but they do not transform it into mechanical energy.
Choice C reason: Potential energy refers to stored energy, such as in a stretched elastic band. While muscles can store potential energy in elastic components, the transformation into mechanical energy is driven by ATP.
Choice D reason: DNA carries genetic information and plays no direct role in energy transformation during muscle contraction.
Choice E reason: Myoglobin stores oxygen in muscle cells but does not provide energy. It supports aerobic metabolism, which ultimately produces ATP, the actual energy source.
Similar Questions
Which of the following movements does NOT increase or decrease the angle between bones?
A. Abduction
Abduction is the movement of a limb away from the midline of the body, which increases the angle between the limb and the trunk.
B. Flexion
Flexion decreases the angle between two bones, such as bending the elbow or knee.
C. Rotation
Rotation involves turning a bone around its longitudinal axis, such as turning the head side to side. It does not change the angle between bones, making it the correct answer.
D. Adduction
Adduction is the movement of a limb toward the midline of the body, decreasing the angle between the limb and the trunk.
E. Circumduction
Circumduction is a circular movement that combines flexion, extension, abduction, and adduction. It involves changes in angles between bones throughout the motion.
Full Explanation
Choice A reason: Abduction is the movement of a limb away from the midline of the body, which increases the angle between the limb and the trunk.
Choice B reason: Flexion decreases the angle between two bones, such as bending the elbow or knee.
Choice C reason: Rotation involves turning a bone around its longitudinal axis, such as turning the head side to side. It does not change the angle between bones, making it the correct answer.
Choice D reason: Adduction is the movement of a limb toward the midline of the body, decreasing the angle between the limb and the trunk.
Choice E reason: Circumduction is a circular movement that combines flexion, extension, abduction, and adduction. It involves changes in angles between bones throughout the motion.
In an isotonic contraction, the muscle:
A. rapidly resynthesizes creatine phosphate and ATP
This choice confuses metabolic processes with mechanical muscle activity. While creatine phosphate and ATP are essential for muscle contraction, their resynthesis is not specific to isotonic contraction. These energy molecules are replenished during recovery phases and are not the defining feature of isotonic contractions.
B. maintains the same length while generating tension
This describes isometric contraction, not isotonic. In isometric contractions, the muscle generates force without changing its length—such as holding a plank position. Isotonic contractions, by contrast, involve a change in muscle length.
C. changes length while maintaining constant tension
This is the correct answer. Isotonic contractions involve the muscle changing length while maintaining constant tension. There are two types: concentric (muscle shortens) and eccentric (muscle lengthens). These contractions are typical in dynamic movements like lifting or lowering weights.
D. remains relaxed and passive during movement
This is incorrect. Muscles do not remain relaxed during isotonic contractions. Instead, they actively contract and generate force to produce movement. Passive relaxation does not contribute to the mechanics of isotonic contraction.
Full Explanation
Choice A reason: This choice confuses metabolic processes with mechanical muscle activity. While creatine phosphate and ATP are essential for muscle contraction, their resynthesis is not specific to isotonic contraction. These energy molecules are replenished during recovery phases and are not the defining feature of isotonic contractions.
Choice B reason: This describes isometric contraction, not isotonic. In isometric contractions, the muscle generates force without changing its length—such as holding a plank position. Isotonic contractions, by contrast, involve a change in muscle length.
Choice C reason: This is the correct answer. Isotonic contractions involve the muscle changing length while maintaining constant tension. There are two types: concentric (muscle shortens) and eccentric (muscle lengthens). These contractions are typical in dynamic movements like lifting or lowering weights.
Choice D reason: This is incorrect. Muscles do not remain relaxed during isotonic contractions. Instead, they actively contract and generate force to produce movement. Passive relaxation does not contribute to the mechanics of isotonic contraction.
_____ are the most movable joints.
A. symphyses
Symphyses are cartilaginous joints where bones are joined by fibrocartilage. They allow limited movement, such as in the pubic symphysis, but are not the most movable joints.
B. synovial joints
Synovial joints are the most movable type of joints in the body. They feature a joint cavity filled with synovial fluid, which reduces friction and allows for a wide range of motion. Examples include the shoulder, hip, and knee joints.
C. syndesmoses
Syndesmoses are fibrous joints where bones are connected by ligaments. They allow more movement than sutures but are still relatively limited compared to synovial joints.
D. gomphoses
Gomphoses are immovable joints found between teeth and their sockets. These joints are highly stable but do not permit movement.
E. synchondroses
ynchondroses are cartilaginous joints where bones are joined by hyaline cartilage. These joints are typically immovable or allow very slight movement, such as in the epiphyseal plates of growing bones.
Full Explanation
Choice A reason: Symphyses are cartilaginous joints where bones are joined by fibrocartilage. They allow limited movement, such as in the pubic symphysis, but are not the most movable joints.
Choice B reason: Synovial joints are the most movable type of joints in the body. They feature a joint cavity filled with synovial fluid, which reduces friction and allows for a wide range of motion. Examples include the shoulder, hip, and knee joints.
Choice C reason: Syndesmoses are fibrous joints where bones are connected by ligaments. They allow more movement than sutures but are still relatively limited compared to synovial joints.
Choice D reason: Gomphoses are immovable joints found between teeth and their sockets. These joints are highly stable but do not permit movement.
Choice E reason: Synchondroses are cartilaginous joints where bones are joined by hyaline cartilage. These joints are typically immovable or allow very slight movement, such as in the epiphyseal plates of growing bones.