GMS 6474 Final Exam 2024 Questions and Answers (GRADED A+)
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Course
GMS 6474
Institution
GMS 6474
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-f...
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
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