Myosin
- Created by: RebeccaSmithySmith
- Created on: 17-12-18 16:59
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- Module 5.5 Myosin and Muscles continued (Part 4 of mindmaps)
- 1.
- Muscle at rest
- Myosin heads are not attached to binding sites on actin because it is blocked by the tropomyosin
- Muscle at rest
- 2.
- Muscle stimulation
- a nerve impulse depolarises
the sarcolemma of the muscle fibres.
- Transverse tubules (t-tubules) transmit this depolarisation rapidly throughout the fibres.
- a nerve impulse depolarises
the sarcolemma of the muscle fibres.
- Muscle stimulation
- 3.
- The role of Calcium
- ca2+ enter the the myofibril
from the sarcoplasmic retiululm.
- the ca2+ binds to troponin
causing a confrontational change (shape change)
- Troponin moves the tropomyosin away to unveil actin binding areas
- the ca2+ binds to troponin
causing a confrontational change (shape change)
- ca2+ enter the the myofibril
from the sarcoplasmic retiululm.
- The role of Calcium
- 5.
- Myosin leaves
- Fresh supplies of ATP bind to
myosin heads.
- This breaks the connection with the binding sites
- ATP is hydrolysed to ADP+P,
which returns myosin heads to starting positions
- if calcium is still present the
myosin head will bind and kick again
- the sarcoplasmic reticulum cantians many ca+ pumps
- theses pumpca+ out of the sarcoplasm and into the sarcoplasmic membrane
- if no other action potential is generated from motor neurons to sarcolamma then ca+ is immediatly recovered from tropin
- Troponin undergoes another conformational change which pulls the tropomyosin back over the actin binding sites
- if no other action potential is generated from motor neurons to sarcolamma then ca+ is immediatly recovered from tropin
- theses pumpca+ out of the sarcoplasm and into the sarcoplasmic membrane
- the sarcoplasmic reticulum cantians many ca+ pumps
- if calcium is still present the
myosin head will bind and kick again
- ATP is hydrolysed to ADP+P,
which returns myosin heads to starting positions
- This breaks the connection with the binding sites
- Fresh supplies of ATP bind to
myosin heads.
- Myosin leaves
- 4.
- Myosin binds
- myosin heads immediately bind
to the available binding sites
- Myosin releases ADP+P
(inorganic phosphate) which causes the myosin head to 'kick back'
- Actin is pulled towards the centre of the sarcomere (H-zone)
- Myosin releases ADP+P
(inorganic phosphate) which causes the myosin head to 'kick back'
- myosin heads immediately bind
to the available binding sites
- Myosin binds
- 1.
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