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1. what does the SR store proteins and calcium
2. what is the role of the allow inside of muscle to communicate with the
transverse tubules in the outside of the muscle
muscle fiber
3. how is a sarcomere measured from z-disc to z-disc
4. what is contained in the I band of thin filaments
the sarcomere & what color is titin
the band
z-disc
light (isotropic)
5. what is contained in the A band of the thick filaments
sarcomere & what color is the bandthin filaments
dark (scatters light)
6. what is contained in the H thick filaments light
zone & what color is the no barbs or myosin
band middle zone of the sarcomere
7. what is contained in the M line in the middle of the sarcomere, middle of H zo
thick filaments
myomesin
8. what does titin do in the sarcomere structural protein
9. how many zones can you see all zones can be seen in relaxed state
when the sarcomere is
relaxed
sarcomere
10. how many zones can be seen
shortens I band
when the sarcomere is
shortens
contracted
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,GMS 6474 final exam questions n answers already
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H zone disappears
thick and thin filaments overlap DONT shorten
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,GMS 6474 final exam questions n answers already
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11. what is the contractile unit of the sarcomere
skeletal muscle
12. what is the main component of
myosin
the thick filaments
have heavy and light chains
motor heads that move it along the thin filame
13. what is the largest protein in the body titin
14. what are the main components of the actin (where myosin binds)
thin filaments troponin (moves tropomyosin when Ca2+ is pre-
sent)
tropomyosin (covers actin active site) nebulin
(sets thin filament length)
CapZ (anchors actin to Z-line on z-disc side)
Tropomodulin (on end of actin, in middle of sa
comere)
alpha-actinin (anchors actin to z-line)
15. what does desmin do in the
interacts with alpha-actinin to anchor z-disc to sar-
sarcom- ere
colemma
16. what does dystrophin do in the
connects sarcomere to sarcolemma
sar- comere
stabilizes the sarcolemma to prevent damage dur-
ing contractions
17. 1st step of cross-bridge cycle BINDING
activated myosin binds to actin
ADP and Pi are still bound to myosin
18. 2nd step of cross bridge cycle POWER STROKE
myosin head swivels
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movement of actin filament
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