GMS 6474 final exam questions with
complete solutions graded A+
what does the SR store - correct answer ✔✔proteins and calcium
what is the role of the transverse tubules in the muscle fiber - correct answer ✔✔allow inside of muscle
to communicate with the outside of the muscle
how is a sarcomere measured - correct answer ✔✔from z-disc to z-disc
what is contained in the I band of the sarcomere & what color is the band - correct answer ✔✔thin
filaments
titin
z-disc
light (isotropic)
what is contained in the A band of the sarcomere & what color is the band - correct answer ✔✔thick
filaments
thin filaments
dark (scatters light)
what is contained in the H zone & what color is the band - correct answer ✔✔thick filaments
light
no barbs or myosin
middle zone of the sarcomere
what is contained in the M line - correct answer ✔✔in the middle of the sarcomere, middle of H zone
thick filaments
,myomesin
what does titin do in the sarcomere - correct answer ✔✔structural protein
how many zones can you see when the sarcomere is relaxed - correct answer ✔✔all zones can be seen
in relaxed state
how many zones can be seen when the sarcomere is contracted - correct answer ✔✔sarcomere
shortens
I band shortens
H zone disappears
thick and thin filaments overlap DONT shorten
what is the contractile unit of skeletal muscle - correct answer ✔✔the sarcomere
what is the main component of the thick filaments - correct answer ✔✔myosin
have heavy and light chains
motor heads that move it along the thin filament
what is the largest protein in the body - correct answer ✔✔titin
what are the main components of the thin filaments - correct 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 - correct answer ✔✔interacts with alpha-actinin to anchor z-disc
to sarcolemma
what does dystrophin do in the sarcomere - correct answer ✔✔connects sarcomere to sarcolemma
stabilizes the sarcolemma to prevent damage during contractions
1st step of cross-bridge cycle - correct answer ✔✔BINDING
activated myosin binds to actin
ADP and Pi are still bound to myosin
2nd step of cross bridge cycle - correct 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 - correct answer ✔✔DISSOSCIATION
ATP binds to myosin
Actin and myosin dissociate (cross bridge detaches)
4th step of cross bridge cycle - correct 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 - correct 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 - correct 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 - correct answer ✔✔release from rigor state
re-energize/reactivate myosin heads for next cycle
what resequesters Ca2+ to end muscle contraction - correct answer ✔✔SERCA
where is the sarcoplasmic reticulum located - correct answer ✔✔wrapped around the sarcomeres and
throughout the myofibrils
what is the role of the sarcoplasmic reticulum in muscle cells - correct answer ✔✔stores Ca2+ that is
needed for contraction
what are the components of the triad in the muscle cell - correct answer ✔✔sarcoplasmic reticulum
t-tubule
what is the role of the triad in the muscle cell - correct answer ✔✔communication center
what are the two main receptors in the triad - correct answer ✔✔dihydropyridine receptors (DHPR)
ryanodine receptors (RyR)
what is the role of the DHPR in the triad - correct answer ✔✔voltage sensor
sense when action potential is moving down t-tubule
what is the role of the RyR in the triad - correct answer ✔✔Ca2+ release channel
what kind of pennate muscle fiber formation has the most force production - correct answer
✔✔multipennate
complete solutions graded A+
what does the SR store - correct answer ✔✔proteins and calcium
what is the role of the transverse tubules in the muscle fiber - correct answer ✔✔allow inside of muscle
to communicate with the outside of the muscle
how is a sarcomere measured - correct answer ✔✔from z-disc to z-disc
what is contained in the I band of the sarcomere & what color is the band - correct answer ✔✔thin
filaments
titin
z-disc
light (isotropic)
what is contained in the A band of the sarcomere & what color is the band - correct answer ✔✔thick
filaments
thin filaments
dark (scatters light)
what is contained in the H zone & what color is the band - correct answer ✔✔thick filaments
light
no barbs or myosin
middle zone of the sarcomere
what is contained in the M line - correct answer ✔✔in the middle of the sarcomere, middle of H zone
thick filaments
,myomesin
what does titin do in the sarcomere - correct answer ✔✔structural protein
how many zones can you see when the sarcomere is relaxed - correct answer ✔✔all zones can be seen
in relaxed state
how many zones can be seen when the sarcomere is contracted - correct answer ✔✔sarcomere
shortens
I band shortens
H zone disappears
thick and thin filaments overlap DONT shorten
what is the contractile unit of skeletal muscle - correct answer ✔✔the sarcomere
what is the main component of the thick filaments - correct answer ✔✔myosin
have heavy and light chains
motor heads that move it along the thin filament
what is the largest protein in the body - correct answer ✔✔titin
what are the main components of the thin filaments - correct 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 - correct answer ✔✔interacts with alpha-actinin to anchor z-disc
to sarcolemma
what does dystrophin do in the sarcomere - correct answer ✔✔connects sarcomere to sarcolemma
stabilizes the sarcolemma to prevent damage during contractions
1st step of cross-bridge cycle - correct answer ✔✔BINDING
activated myosin binds to actin
ADP and Pi are still bound to myosin
2nd step of cross bridge cycle - correct 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 - correct answer ✔✔DISSOSCIATION
ATP binds to myosin
Actin and myosin dissociate (cross bridge detaches)
4th step of cross bridge cycle - correct 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 - correct 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 - correct 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 - correct answer ✔✔release from rigor state
re-energize/reactivate myosin heads for next cycle
what resequesters Ca2+ to end muscle contraction - correct answer ✔✔SERCA
where is the sarcoplasmic reticulum located - correct answer ✔✔wrapped around the sarcomeres and
throughout the myofibrils
what is the role of the sarcoplasmic reticulum in muscle cells - correct answer ✔✔stores Ca2+ that is
needed for contraction
what are the components of the triad in the muscle cell - correct answer ✔✔sarcoplasmic reticulum
t-tubule
what is the role of the triad in the muscle cell - correct answer ✔✔communication center
what are the two main receptors in the triad - correct answer ✔✔dihydropyridine receptors (DHPR)
ryanodine receptors (RyR)
what is the role of the DHPR in the triad - correct answer ✔✔voltage sensor
sense when action potential is moving down t-tubule
what is the role of the RyR in the triad - correct answer ✔✔Ca2+ release channel
what kind of pennate muscle fiber formation has the most force production - correct answer
✔✔multipennate
