Binding of the myosin head sequentailly prevents "_____________" of the thin filament. This makes it seem that the myosin is "_______" the actin ______.
Calcium ions are moved back into the SR by the process known as ____________ which is facilitated by specialized _________________. This process requires___.
Calcium Ion Pumps
During muscle contraction, the ________shortens but the __________remains the same.
Flexing the myosin head provides what is known as the ________.
Hydrolysis of ATP returns the myosin head to its ____________conformation.
Name 3 roles of ATP in the contraction of muscle.
Energizes power stroke of myosin head
Disconnects myosin head from actin
Actively transports calcium ions back to the sarcoplasmic reticulum
The myosin head contains binding sites for what 2 molecules?
The thick filament is composed of what molecule?
True or False.
When a muscle contracts, all crossbridges are synchronized to bind and disconnect at the same time.
False. Not all crossbridges will bind and disconnect at the same time, because is this were done, the thin filament would never be moved forward, contracting the sarcomere. The myosin heads bind at different times to prevent the thin filament backsliding so as to "walk" the filament continually forward.
Waht are the 3 molecules that make up the thin filament?
What are the 6 steps of the cross bridge cycling?
Influx of calcium ions
Binding of myosin to actin
Power stroke, causing sliding of thin filaments
Binding of ATP to cross bridge
Hydrolysis of ATP
Transfer of calcium ions back to the SR
What is the name of the condition in which muscles become rigid after death?
What molecule is connected to the z-line?
What molecule must bind to the myosin head in order for it to disconnect from the actin?
What triggers the condition of body rigidity posthumously?
No ATP synthesis=ATP depletion=No disconnect of myosn head from actin, keeping muscles in a temporary (several hours) contracted state.
What triggers the release of calcium ions?
Action potential is passed down the T-tubules to the