Date | May 2019 | Marks available | 1 | Reference code | 19M.2.SL.tz0.3 |
Level | Standard Level | Paper | Paper 2 | Time zone | time zone 0 |
Command term | State | Question number | 3 | Adapted from | N/A |
Question
The diagram shows a skeletal muscle.
Identify the structures A, B and C in the diagram.
Define the term origin of a muscle.
Explain the role of ATP in providing energy for a sprinter’s muscles to contract.
Explain reciprocal inhibition during knee extension when kicking.
The diagram shows the lower leg.
Identify the elements A, B and C of the lever system.
Using anatomical terminology, state the location of the tibia relative to the femur.
Using anatomical terminology, state the location of the fibula relative to the tibia.
Using anatomical terminology, state the location of the patella relative to the tibia.
Markscheme
A: epimysium ✔
B: muscle fibre/muscle cell/endomysium ✔
C: perimysium/ «muscle» fascicle ✔
[3]
«often proximal» attachment of a muscle tendon to a stationary bone ✔
Must refer to stationary/non-moving/fixed end.
[1]
myosin heads use the breakdown of ATP to trigger the contraction process ✔
the breakdown of ATP to ADP releases phosphate molecule ✔
the release of a phosphate molecule provides the energy for muscle contraction ✔
ATP reattaches to the myosin head and this causes the detachment of the cross bridge ready for the next phase if necessary ✔
during sprinting the ATP will come from stores (2 seconds approximately) / from the ATP-PC system ✔
depending on the length of the sprint the lactic acid process will provide sources of ATP ✔
[3]
reciprocal inhibition is a neuromuscular reflex that inhibits opposing muscles «to enable voluntary movements» ✔
the quadriceps act as the agonist / concentrically contracting ✔
the hamstrings act as the antagonist / relaxing to enable knee extension ✔
[3]
A: effort/muscular force ✔
B: load/resistance force ✔
C: fulcrum/pivot ✔
[3]
Inferior
OR
distal ✔
[1]
posterior
OR
lateral ✔
[1]
anterior
OR
proximal
OR
superior ✔
[1]
Examiners report
Many candidates did not get endomysium and perimysium correct. There were many spelling mistakes. A few students struggled to use the correct anatomical terminology: -osteum instead of – mysium or described it as a nerve fibre or some other part of the body. This indicates that they did not read the descriptor indicating it was a diagram of a skeletal muscle.
Many candidates did not mention that it was a tendon attached to a ‘stationary bone’
Not many students were able to get full marks for the role of ATP in muscle contraction. Most understood that ATP is split into ADP + P and that this is somehow connected to contraction, but in general student knowledge of how the power stroke occurs was poorly associated to this process.
About half of candidates scored more than 2 on this question. Again, the clarity of student’s answers generally held them back.
This was either very poorly or well done. The fulcrum was most often correct with the other components sometimes mixed up or the student wrote “force” for the effort force which was too vague.
The results for this were mixed – most knew the relationship for the tibia and femur and the patella to the tibia but struggled with the fibula to the tibia.
A few students clearly did not know what they were being asked for and they listed several conflicting options (e.g. inferior, superior), and a few did not use appropriate anatomical terminology.
The results for this were mixed – most knew the relationship for the tibia and femur and the patella to the tibia but struggled with the fibula to the tibia.
A few students clearly did not know what they were being asked for and they listed several conflicting options (e.g. inferior, superior), and a few did not use appropriate anatomical terminology
The results for this were mixed – most knew the relationship for the tibia and femur and the patella to the tibia but struggled with the fibula to the tibia.
A few students clearly did not know what they were being asked for and they listed several conflicting options (e.g. inferior, superior), and a few did not use appropriate anatomical terminology