Lesson Worksheet: Muscle Contraction Biology

In this worksheet, we will practice describing the structure of a neuromuscular junction and outlining the sliding filament theory of muscle contraction.

Q1:

Which of the following best describes the structure of an actin filament?

  • AA thin filament that is made up of two molecules twisted around each other
  • BA thick filament with a globular head and a cylindrical tail

Q2:

In the sliding filament theory of muscle contraction, what initiates the detachment of the myosin head from the binding site on the actin filament?

  • AA molecule of ATP binding to the myosin head
  • BThe hydrolysis of an ADP molecule on the actin filament
  • CCalcium ions binding to tropomyosin
  • DA molecule of ADP being released from the myosin head

Q3:

The flowchart provided describes the events that occur at a neuromuscular junction, with each step assigned a number. State the number sequence that would give the correct order of events.

  • A6, 2, 1, 4, 3, 5
  • B5, 2, 1, 4, 3, 6
  • C6, 2, 4, 3, 1, 5
  • D1, 2, 6, 4, 3, 5
  • E3, 4, 6, 2, 1, 5

Q4:

Where does a neuromuscular junction form?

  • ABetween the axon of a motor neuron and a muscle fiber
  • BBetween the axon of a motor neuron and the dendrite of another neuron
  • CBetween the axon of a motor neuron and the dendrite of a sensory neuron
  • DBetween the dendrite of a sensory neuron and a muscle fiber

Q5:

Which of the following best describes the structure of a myosin filament?

  • AA thin filament that is made up of two molecules twisted around each other
  • BA thick filament with a globular head and a cylindrical tail

Q6:

In the sliding filament theory of muscle contraction, how does the myosin head resume its normal position?

  • AUsing energy from the breakdown of ADP
  • BUsing the electrical stimulation of the influx of calcium ions
  • CUsing energy from the hydrolysis of ATP

Q7:

In the sliding filament theory of muscle contraction, what is the primary role of calcium ions?

  • ATo provide the energy required to return the myosin heads back to their normal position
  • BTo initiate the release of a molecule of ADP as the myosin heads pull the actin filament along
  • CTo stimulate the detachment of the myosin heads from the actin binding sites
  • DTo bind to tropomyosin, changing its shape and moving it away from myosin binding sites

Q8:

The diagram provided shows the stages of the sliding filament theory. State the correct order.

  • A5, 3, 2, 7, 8, 6, 4, 1
  • B3, 2, 5, 6, 8, 7, 4, 1
  • C3, 2, 5, 7, 8, 6, 4, 1
  • D8, 6, 4, 1, 3, 2, 5, 7

Q9:

The diagram provided shows a basic outline of a neuromuscular junction.

What is the role of acetylcholine at a neuromuscular junction?

  • ATo open the voltage-gated calcium channels on the presynaptic neuron
  • BTo act as a biological catalyst
  • CTo act as a chemical neurotransmitter
  • DTo move tropomyosin away from the myosin-binding sites on actin filaments

Q10:

The diagram provided shows how a sarcomere changes when a muscle fiber contracts. Which of the following best describes how the sarcomere changes?

  • AThe sarcomere extends as the actin filaments pull the myosin away from the M line.
  • BThe sarcomere shortens as the myosin pulls the actin filaments toward the M line.

This lesson includes 22 additional questions for subscribers.

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