Biol 436 Practice Test Questions and
Correct Answers
Sarcomere ✅-the basic unit of muscle contraction
-Lined up to form the long structure (myofibril)
-2 major elements of sarcomere
-Actin (thin filament)= stabilized by tropomyosin, activated by troponin
-myosin (thick filament)
-Stabilized by titan and Nebulin
-Z disk on either end, shared with next sarcomere over
Nebulin ✅anchors each thin actin filaments together at the center of the sarcomere
Titan ✅-Largest protein known to be made in cells.
-Extends from Z-disk and tethers the thick filaments to the Z-disk
Actin ✅-Thin filament of sarcomere
-Form a double stranded pearl necklace
-They have a binding site for myosin
Myosin ✅-Thick Filaments of sarcomere
Head consists of
-Actin binding site that binds with myosin binding site on thin filaments (Actin)
(accomplishes cross-bridging)
-Myosin ATPase site (takes ATP and hydrolyzes it to ADP)
Troponin ✅protein complex that can bind calcium, which causes it to change shape
and roll the tropomyosin out of the way and exposes the myosin binding site on actin.
Tropomyosin ✅Wraps around actin molecules which stabilizes the structure and
covers up the myosin binding site in a resting state.
Muscle Fiber ✅(muscle cells)
Consists of sarcolemma (outside membrane)
T-Tubules (how AP is carried into the interior of muscle fiber)
Sarcoplasm=fluid inside muscle fiber
Rigor Mortis ✅when myosin head group is attached to the actin subunits, requires
binding of ATP to release the 2 molecules.
Rigor Mortis= no more ATP
Correct Answers
Sarcomere ✅-the basic unit of muscle contraction
-Lined up to form the long structure (myofibril)
-2 major elements of sarcomere
-Actin (thin filament)= stabilized by tropomyosin, activated by troponin
-myosin (thick filament)
-Stabilized by titan and Nebulin
-Z disk on either end, shared with next sarcomere over
Nebulin ✅anchors each thin actin filaments together at the center of the sarcomere
Titan ✅-Largest protein known to be made in cells.
-Extends from Z-disk and tethers the thick filaments to the Z-disk
Actin ✅-Thin filament of sarcomere
-Form a double stranded pearl necklace
-They have a binding site for myosin
Myosin ✅-Thick Filaments of sarcomere
Head consists of
-Actin binding site that binds with myosin binding site on thin filaments (Actin)
(accomplishes cross-bridging)
-Myosin ATPase site (takes ATP and hydrolyzes it to ADP)
Troponin ✅protein complex that can bind calcium, which causes it to change shape
and roll the tropomyosin out of the way and exposes the myosin binding site on actin.
Tropomyosin ✅Wraps around actin molecules which stabilizes the structure and
covers up the myosin binding site in a resting state.
Muscle Fiber ✅(muscle cells)
Consists of sarcolemma (outside membrane)
T-Tubules (how AP is carried into the interior of muscle fiber)
Sarcoplasm=fluid inside muscle fiber
Rigor Mortis ✅when myosin head group is attached to the actin subunits, requires
binding of ATP to release the 2 molecules.
Rigor Mortis= no more ATP
