11 mark
The diagram shows the structures in a human elbow.
Which numbers represent a pair of antagonistic muscles?
I and II
V and IV
VI and II
II and III
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Syllabus Edition
First teaching 2023
First exams 2025
|
Muscle & Motility (HL IB Biology)
Exam Questions
1 hour22 questions
2
1 mark
1 markWhich row correctly identifies the features of the myofibril shown in the diagram.
| I. | II. | III. | IV. | |
| A | Z-line | Sarcomere | A-band | H-zone |
| B | H-zone | A-band | Z-line | I-band |
| C | Sarcomere | H-zone | I-band | Z-line |
| D | Sarcomere | I-band | A-band | Z-line |
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11 mark
Identify which answer gives the correct labels when describing how the skeleton can act as a lever.
| X | Y | Z | |
| A | Fulcrum | Effort | Load |
| B | Effort | Load | Fulcrum |
| C | Fulcrum | Load | Effort |
| D | Load | Fulcrum | Effort |
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21 mark
Which of the following is not a range of movement demonstrated by a synovial joint such as an elbow or knee joint?
Abduction
Flexion
Extension
Inversion
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31 mark
The diagram below shows the sarcomere of a muscle fibre.
Which of the following statements correctly describes the events observed during a muscle contraction?
The length of the sarcomere stays the same, the dark band gets longer and the light bands stay the same
The length of the sarcomere gets shorter, the dark band gets shorter and the distance between the two Z lines gets shorter
The length of the sarcomere stays the same, the dark band gets longer and the distance between the two Z lines gets shorter
The length of the sarcomere gets shorter, the dark band stays the same and the light bands get shorter
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41 mark
One myosin powerstroke requires hydrolysis of one molecule of ATP and moves one actin filament 20 nm.
How many ATP molecules would be required to move a single actin filament 0.3 µm when the sarcomere contracts?
150 ATP
15 ATP
20 ATP
1.5 ATP
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51 mark
Which of the following describes a function of ATP in muscle contraction?
To actively transport calcium ions into myofibrils from the sarcoplasmic reticulum
To move tropomyosin and expose myosin binding sites
To allow crossbridge formation
To cause cocking of the myosin head
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61 mark
Phosphocreatine is a chemical found in the muscles of vertebrates. It provides a store of phosphate ions used during muscle contraction. The graph shows the effect of phosphocreatine production on the force of muscle contraction in mice.
Which of the following best explains the results shown in the graph?
Mice that can produce phosphocreatine can run faster.
Phosphate ions can be combined with ADP to make ATP for contraction.
Phosphate ions initiate the formation of crossbridges.
Phosphate ions inhibit muscle contraction by creating an electrochemical gradient.
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71 mark
Identify the correct label from the electron micrograph which correctly represents the transverse section of muscle fibre shown.
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11 mark
1 markRigor mortis describes the stiffening of body muscles due to chemical change in myofibrils after death. Knowledge of the stages of rigor mortis allows pathologists to estimate the time of death accurately.
Algor mortis refers to the gradual decrease in the body's temperature after death.
The graph shows the onset of Rigor mortis and Algor mortis after death.
Which of the following options shows a valid explanation for the trends shown in the graph?
| Trend | Explanation | |
| A | Body temperature decreases from 0 to 36 hours after death | Calcium is not replenished due to lack of ATP |
| B | Rigor mortis peaks at 12 hours after death | ATP is no longer available to break actin-myosin cross bridges |
| C | Body temperature increases slightly 36 hours after death | Energy is released from hydrolysis of the remaining ATP |
| D | Rigor mortis increases gradually after death | ATP becomes depleted so muscles cannot remain relaxed. |
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