WorksheetsMuscle Contraction and Neuromuscular Junction Review
Total questions: 25
Worksheet time: 14mins
What are the two main filaments involved in muscle contraction?
Actin and myosin
Collagen and elastin
Keratin and fibrin
Tubulin and dynein
What happens to the Z-lines during muscle contraction?
They move apart
They get closer together
They disappear
They become thicker
What happens to the sarcomere during muscle contraction?
It elongates
It shortens
It remains unchanged
It thickens
What is the source of energy for muscle contraction?
Glucose
ATP
Oxygen
Fatty acids
What is the role of calcium ions in the muscle contraction process shown in the diagram?
To provide energy
To bind to troponin
To break down ATP
To release ADP
Which protein does the myosin head bind to during muscle contraction?
Troponin
Tropomyosin
Actin
Myoglobin
What is released from the myosin head after the power stroke (flex)?
ATP
ADP and phosphate
Calcium
Glucose
Which molecule is responsible for the detachment (release) of the myosin head from actin after the power stroke?
ADP
ATP
Calcium
Phosphate
Which filament pulls on the thinner filament during muscle contraction?
Myosin
Actin
Sarcomere
Calcium
What is the thinner filament that is pulled during muscle contraction?
Myosin
Actin
ATP
Calcium
Why are neurotransmitters necessary at the neuromuscular junction?
They provide energy for muscle contraction.
They act as a bridge for action potentials to cross the synaptic cleft.
They directly stimulate muscle fibers to contract.
They prevent muscle fatigue.
Which specific neurotransmitter is released during this process?
Dopamine
Serotonin
Acetylcholine
GABA
Identify the following protein channels as either voltage-gated channels or chemically-gated channels: The Calcium channels on the axon terminal.
Voltage-gated channels
Chemically-gated channels
Mechanically-gated channels
Light-gated channels
Identify the following protein channels as either voltage-gated channels or chemically-gated channels: The channels found on the sarcolemma of the muscle fiber.
Voltage-gated channels
Chemically-gated channels
Mechanically-gated channels
Light-gated channels
Identify the following protein channels as either voltage-gated channels or chemically-gated channels: The channels along the T-tubules.
Voltage-gated channels
Chemically-gated channels
Mechanically-gated channels
Light-gated channels
What is the function of troponin in muscle contraction?
To transport oxygen
To bind calcium ions
To hydrolyze ATP
To release neurotransmitters
Which ion is primarily responsible for initiating the action potential in muscle fibers?
Calcium
Chloride
Potassium
Sodium
What structural change occurs in the myosin head during the power stroke?
It detaches from actin
It pivots and pulls actin
It binds to ATP
It releases calcium
What is the role of tropomyosin in muscle contraction?
To bind calcium ions
To block myosin binding sites on actin
To hydrolyze ATP
To release neurotransmitters
Which ion is released from the sarcoplasmic reticulum to initiate muscle contraction?
Chloride
Sodium
Potassium
Calcium
What is the primary function of the sarcoplasmic reticulum in muscle cells?
To store calcium ions
To produce ATP
To synthesize proteins
To transport oxygen
What triggers the release of calcium ions from the sarcoplasmic reticulum?
Action potential
ATP hydrolysis
Muscle relaxation
Protein synthesis
When myosin heads make a cross bridge and bend pulling the actin myofilament toward the center of the sarcomere, it is called the _______________________.
ATP Contraction
power stroke (flex)
neuromuscular junction
return stroke
How much ATP is used in each myosin/actin cross-bridge cycle?
1
2
3
4
Reorder the following stages that occur with myosin during the sliding filament theory:
ATP is cleaved into ADP and phosphate cocking the myosin head back
The myosin head will extend and attach to the exposed binding site on actin
The myosin head flexes pulling the actin filament towards the m-line; ADP and phosphate leave the myosin head
ATP attaches to the myosin head releasing it from actin
