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WorksheetsUnderstanding Muscle Contraction Mechanisms
Total questions: 10
Worksheet time: 5mins
What is the primary role of calcium ions in muscle contraction?
To provide energy for muscle contraction
To bind to troponin, causing a conformational change that exposes binding sites on actin
To break down ATP into ADP and inorganic phosphate
To transmit nerve impulses across the neuromuscular junction
What is the function of the sarcoplasmic reticulum in muscle cells?
To store and release calcium ions
To generate action potentials
To synthesise proteins
To transport oxygen
During cross-bridge cycling, what happens immediately after the myosin head binds to actin?
ATP binds to the myosin head
The myosin head pivots, pulling the actin filament
Calcium ions are released from the sarcoplasmic reticulum
The myosin head detaches from actin
What is the sliding filament theory?
A theory that explains how muscles generate heat
A theory that describes how actin and myosin filaments slide past each other to produce muscle contraction
A theory that details the synthesis of ATP in muscle cells
A theory that explains the transmission of nerve impulses
What happens to the sarcomere during muscle contraction?
It elongates
It shortens
It remains the same length
It disintegrates
Which molecule provides the energy for the power stroke in cross-bridge cycling?
Glucose
ATP
ADP
Creatine phosphate
What is the role of tropomyosin in muscle contraction?
It binds to calcium ions
It covers the binding sites on actin when the muscle is relaxed
It hydrolyses ATP
It transmits nerve impulses
Which part of the myosin molecule binds to actin?
The tail
The hinge region
The head
The neck
What happens to the levels of calcium ions in the sarcoplasm when a muscle relaxes?
They increase
They decrease
They remain constant
They fluctuate randomly
Which protein acts as a calcium sensor in muscle cells?
Myosin
Actin
Troponin
Tropomyosin
