GMS 6474 Final Exam 2024 Questions and Answers (GRADED A+)
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Course
GMS 6474
Institution
GMS 6474
what does the SR store - ANSWER-proteins and calcium
what is the role of the transverse tubules in the muscle fiber - ANSWER-allow inside of muscle to communicate with the outside of the muscle
how is a sarcomere measured - ANSWER-from z-disc to z-disc
what is contained in the I band of th...
GMS 6474 Final Exam 2024 Questions and Answers (GRADED A+) what does the SR store - ANSWER-proteins and calcium
what is the role of the transverse tubules in the muscle fiber - ANSWER-allow inside of muscle to communicate with the outside of the muscle
how is a sarcomere measured - ANSWER-from z-disc to z-disc
what is contained in the I band of the sarcomere & what color is the band - ANSWER-
thin filaments titin z-disc
light (isotropic)
what is contained in the A band of the sarcomere & what color is the band - ANSWER-
thick filaments thin filaments dark (scatters light)
what is contained in the H zone & what color is the band - ANSWER-thick filaments light no barbs or myosin middle zone of the sarcomere
what is contained in the M line - ANSWER-in the middle of the sarcomere, middle of H zone thick filaments myomesin
what does titin do in the sarcomere - ANSWER-structural protein
how many zones can you see when the sarcomere is relaxed - ANSWER-all zones can be seen in relaxed state
how many zones can be seen when the sarcomere is contracted - ANSWER-sarcomere
shortens I band shortens H zone disappears thick and thin filaments overlap DONT shorten what is the contractile unit of skeletal muscle - ANSWER-the sarcomere
what is the main component of the thick filaments - ANSWER-myosin
have heavy and light chains motor heads that move it along the thin filament
what is the largest protein in the body - ANSWER-titin
what are the main components of the thin filaments - ANSWER-actin (where myosin binds)
troponin (moves tropomyosin when Ca2+ is present)
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 sarcomere)
alpha-actinin (anchors actin to z-line)
what does desmin do in the sarcomere - ANSWER-interacts with alpha-actinin to anchor z-disc to sarcolemma
what does dystrophin do in the sarcomere - ANSWER-connects sarcomere to sarcolemma stabilizes the sarcolemma to prevent damage during contractions
1st step of cross-bridge cycle - ANSWER-BINDING activated myosin binds to actin ADP and Pi are still bound to myosin
2nd step of cross bridge cycle - ANSWER-POWER STROKE myosin head swivels
movement of actin filament
ADP and Pi released from myosin
(Pi is released first, before ADP is released)
3rd step of cross bridge cycle - ANSWER-DISSOSCIATION
ATP binds to myosin Actin and myosin dissociate (cross bridge detaches)
4th step of cross bridge cycle - ANSWER-ACTIVATION
ATP hydrolysis energy activates myosin head ADP and Pi remain bound to myosin if Ca2+ still present, cycle continues
how does Ca2+ effect the cross bridge cycle - ANSWER-Ca2+ is needed for the troponin to move the tropomyosin off the actin
when Ca2+ runs out, the cross bridge cycle will stop troponin has 4 Ca2+ binding sites
how does Ca2+ get into the cell to trigger the cross bridge cycle - ANSWER-through the
RyR channels, which are activated by the DHPR channel mechanical change IN SKELETAL MUSCLES
what are the two roles of ATP in the cross bridge cycle - ANSWER-release from rigor state re-energize/reactivate myosin heads for next cycle
what resequesters Ca2+ to end muscle contraction - ANSWER-SERCA
where is the sarcoplasmic reticulum located - ANSWER-wrapped around the sarcomeres and throughout the myofibrils
what is the role of the sarcoplasmic reticulum in muscle cells - ANSWER-stores Ca2+ that is needed for contraction
what are the components of the triad in the muscle cell - ANSWER-sarcoplasmic reticulum t-tubule
what is the role of the triad in the muscle cell - ANSWER-communication center
what are the two main receptors in the triad - ANSWER-dihydropyridine receptors (DHPR)
ryanodine receptors (RyR)
what is the role of the DHPR in the triad - ANSWER-voltage sensor
sense when action potential is moving down t-tubule
what is the role of the RyR in the triad - ANSWER-Ca2+ release channel
what kind of pennate muscle fiber formation has the most force production - ANSWER-
multipennate
what muscle fiber arrangement is best for speed - ANSWER-when they are stacked on top of each other (like a building)
what muscle fiber arrangement is best for strength - ANSWER-when they are next to each other (like a trailer) have more tension
what kind of muscle contraction action has the most tension - ANSWER-isometric contraction
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