Worksheets3.6.3 Skeletal muscles
Total questions: 15
Worksheet time: 8mins
What is the primary function of antagonistic muscle pairs?
To compress the skeleton
To work against each other to move bones
To produce hormones
To store calcium ions
Which of the following best describes the ultrastructure of a myofibril?
A single muscle fibre
A bundle of actin and myosin filaments
A collection of muscle cells
A network of blood vessels
What role does calcium ions play in myofibril contraction?
They provide energy for contraction
They bind to tropomyosin to expose binding sites
They bind to actin to initiate contraction
They bind to myosin to initiate contraction
Which molecule is directly responsible for the power stroke in muscle contraction?
Actin
Myosin
ATP
Calcium ions
What is the role of phosphocreatine in muscle contraction?
It stores calcium ions
It provides a rapid source of ATP
It breaks down actin
It forms the actinomyosin bridge
Which of the following is a characteristic of slow skeletal muscle fibres?
They fatigue quickly
They have a high density of mitochondria
They are used for short bursts of power
They contain less myoglobin
Where are fast skeletal muscle fibres typically located?
In muscles used for posture
In muscles used for endurance activities
In muscles used for quick, powerful movements
In the heart
What is the primary role of myosin in muscle contraction?
To bind calcium ions
To hydrolyse ATP
To form cross-bridges with actin
To store energy
How does ATP contribute to muscle relaxation?
By binding to actin
By detaching myosin heads from actin
By increasing calcium ion concentration
By forming cross-bridges
What is the role of tropomyosin in muscle contraction?
It binds to myosin
It covers binding sites on actin
It hydrolyses ATP
It stores calcium ions
Which of the following best describes the structure of skeletal muscle?
A single layer of cells
A bundle of fibres surrounded by connective tissue
A network of neurons
A collection of fat cells
What is the primary energy source for muscle contraction during the first few seconds of intense activity?
Glucose
Phosphocreatine
Fatty acids
Lactic acid
Which of the following is a property of fast skeletal muscle fibres?
High endurance
High myoglobin content
Rapid contraction speed
High resistance to fatigue
What happens to the actinomyosin bridge during muscle contraction?
It breaks down ATP
It forms and breaks repeatedly
It stores calcium ions
It remains static
Which of the following is NOT involved in the contraction of a myofibril?
Actin
Myosin
Tropomyosin
Troponin
