AQA A Level Biology: Topic 6
Study online at https://quizlet.com/_fodtnt
1. Describe the 1) Calcium ions diffuse into myofibrils from the sarcoplas-
roles of calci- mic reticulum
um ions and ATP 2) This causes the movement of tropomyosin on actin
in the contrac- 3) This movement causes the exposure of the binding sites
tion of a myofibril on the actin
4) Myosin heads attach to binding sites on actin
5) The hydrolysis of ATP causes myosin heads to bend
Pulling actin molecules
6) Attachment of new ATP to each myosin head causes
myosin heads to detach from actin sites
2. types of muscles skeletal, smooth, cardiac
3. role of skeletal - attached to bones by tendons
muscle - ligaments attach bones to other ones and hold them
together
- pair of skeletal muscles contract and relax to move a joint
4. what are agnos- - work together to move a bone
tic pairs - contracting muscle is the agonist
- relaxed muscle is the antagonist
5. structure of - sarcolemma: parts fold inwards and form t tubules
skeletal muscle - sarcoplasmic reticulum: has stores of Ca+, lots of mito-
chondria
- sarcomere: what myofibril is made up of
- myofibrils: multinucleate, made up of fibrils for contraction
6. myosin thick filament
7. actin thin filament
8. dark bands A band, overlapping myosin and actin
9. light bands I band, contain thin actin filaments
10. myofibril made up of short units called sarcomere
11. what is the role of actin: binding site for myosin head called actin-myosin
actin and myosin binding site. Tropomyosin is found between actin filaments
1/2
Study online at https://quizlet.com/_fodtnt
1. Describe the 1) Calcium ions diffuse into myofibrils from the sarcoplas-
roles of calci- mic reticulum
um ions and ATP 2) This causes the movement of tropomyosin on actin
in the contrac- 3) This movement causes the exposure of the binding sites
tion of a myofibril on the actin
4) Myosin heads attach to binding sites on actin
5) The hydrolysis of ATP causes myosin heads to bend
Pulling actin molecules
6) Attachment of new ATP to each myosin head causes
myosin heads to detach from actin sites
2. types of muscles skeletal, smooth, cardiac
3. role of skeletal - attached to bones by tendons
muscle - ligaments attach bones to other ones and hold them
together
- pair of skeletal muscles contract and relax to move a joint
4. what are agnos- - work together to move a bone
tic pairs - contracting muscle is the agonist
- relaxed muscle is the antagonist
5. structure of - sarcolemma: parts fold inwards and form t tubules
skeletal muscle - sarcoplasmic reticulum: has stores of Ca+, lots of mito-
chondria
- sarcomere: what myofibril is made up of
- myofibrils: multinucleate, made up of fibrils for contraction
6. myosin thick filament
7. actin thin filament
8. dark bands A band, overlapping myosin and actin
9. light bands I band, contain thin actin filaments
10. myofibril made up of short units called sarcomere
11. what is the role of actin: binding site for myosin head called actin-myosin
actin and myosin binding site. Tropomyosin is found between actin filaments
1/2
