1. 11.2 Movement Essential Idea: The roles of the
musculoskeletal system are movement,
support and protection.
http://www.wiley.com/college/pratt/0471393878/student/animations/actin_myosin/
anim_text.html
By Darren Aherne
2. 11.2 Movement: Essential Idea: The roles of the musculoskeletal system are movement,
support and protection.
Assessment Statement Guidance
11.2
U1
Bones and exoskeletons provide anchorage for muscles and act as levers.
Synovial joints allow certain movements but not others.
11.2
U2
Synovial joints allow certain movements but not others.
11.2
U3
Movement of the body requires muscles to work in antagonistic pairs.
11.2
U4
Skeletal muscle fibres are multinucleate and contain specialized
endoplasmic reticulum.
11.2
U5
Muscle fibres contain many myofibrils.
11.2
U6
Each myofibril is made up of contractile sarcomeres.
11.2
U7
The contraction of the skeletal muscle is achieved by the sliding of actin
and myosin filaments.
3. 11.2 Movement: Essential Idea: The roles of the musculoskeletal system are movement,
support and protection.
Assessment Statement Guidance
11.2
U8
ATP hydrolysis and cross bridge formation
are necessary for the filaments to slide.
11.2
U9
Calcium ions and the proteins
tropomyosin and troponin control muscle
contractions.
11.2
A1
Application: Antagonistic pairs of muscles
in an insect leg.
11.2
A2
Skill: Annotation of a diagram of the
human elbow.
Elbow diagram should include cartilage,
synovial fluid, joint capsule, named bones
and named antagonistic muscles.
11.2
A3
Skill: Drawing labelled diagrams of the
structure of a sarcomere.
Drawing labelled diagrams of the structure
of a sarcomere should include Z lines, actin
filaments, myosin filaments with heads, and
the resultant light and dark bands.
11.2
A4
Skill: Analysis of electron micrographs to
find the state of contraction of muscle
fibres.
Measurement of the length of sarcomeres
will require calibration of the eyepiece scale
of the microscope.
4. 11.2 U1 Bones and exoskeletons provide anchorage for muscles and act
as levers. Synovial joints allow certain movements but not others.
Exoskeleton: hard, protective skeleton on the outside surface of the body-
example: crab, cockroach
Endoskeleton: skeleton on the inside of the body- example: dogs, humans
Skeletons allow movement
by providing attachment
sites for muscles and
working as levers.
Levers change the size and
direction of forces.
E= effort force, F= fulcrum, R= resultant force
From Biology Course Companion, Allott & Mindorf,, Oxford
University Press, 2014, p. 477
5. 11.2 A1 Application: Antagonistic
pairs of muscles in an insect leg.
Insect legs also have antagonistic muscles to flex and extend the joint.
femur
tibia
http://idtools.org/id/grasshoppers/images/f
s_images/M_bruneri_leg_o.jpg
Jumping Action:
1. Extensor muscles relaxed
2. Flexor muscles in femur contract
making leg look Z shaped
3. Extensor muscles contract strongly,
causing tibia to extend, making
insect jump
flex
extend
From Biology Course Companion, Allott & Mindorf,, Oxford
University Press, 2014, p. 478
6. 11.2 U3 Movement of the body requires
muscles to work in antagonistic pairs.
Muscles can only contract- i.e. pull by getting shorter. Muscles cross joints, and work
together in antagonistic pairs- one pulls a joint one direction and its antagonist pulls it
in the opposite direction- example biceps and triceps flex and extend the elbow joint.
Joint: the place where two bones meet
Cartilage: tough smooth tissue that
reduces friction & absorbs shocks
Synovial fluid: lubricates the joint & fills
the
Joint Capsule: seals joint & keeps
synovial fluid
From Biology Course Companion, Allott & Mindorf,, Oxford
University Press, 2014, p. 478
7. 11.2 U2 Synovial joints allow certain movements but not others.
i-biology.net
9. 11.2 U4 Skeletal muscle fibers are multinucleate and contain specialized endoplasmic
reticulum. 11.2 U5 Muscle fibers contain many myofibrils.
i-biology.net
10. 11.2 U6 Each myofibril is made up of contractile sarcomeres.
i-biology.net
11. 11.2 A3 Skill: Drawing labelled diagrams of the structure of a sarcomere.
Draw and label the structure of a sarcomere. (4 marks)
Include:
Z lines, actin filaments, myosin filaments
with heads, and the resultant light and dark
bands
Tips:
• Indicate the sarcomere is between two Z
lines
• Actin filaments connected to Z lines
• Light bands labelled around the Z lines
• Length of dark bands should be indicated
with arrows.
12. Sample mark scheme for a 4 mark question.
Award [1] for each structure clearly drawn and correctly
labelled.
Sarcomere — clearly indicated between Z lines;
Z lines;
actin filaments attached to Z line;
myosin filaments with heads;
(two) light bands;
dark band;
Draw and label the structure of a sarcomere. (4 marks)
From Biology Course Companion, Allott & Mindorf,, Oxford
University Press, 2014, p. 481
13. 11.2 U7 The contraction of the skeletal muscle is achieved
by the sliding of actin and myosin filaments.
http://bcs.whfreeman.com/thelifewire/content/chp47
/4702001.html
http://brookscole.cengage.com/chemistry_d/templates/student_resources/s
hared_resources/animations/muscles/muscles.html
i-biology.net
14. 11.2 U8 ATP hydrolysis and cross bridge formation are
necessary for the filaments to slide.
i-biology.nethttp://www.wiley.com/college/pratt/0471393878/student/a
nimations/actin_myosin/actin_myosin.swf
15. 11.2 U9 Calcium ions and the proteins tropomyosin and
troponin control muscle contractions.
i-biology.net
16. 11.2 A4 Skill: Analysis of electron micrographs to find the
state of contraction of muscle fibres.
i-biology.net
