1
Expert solutions
bio 2301 exam #3 Questions and Answers
(100% Correct Answers) Already Graded A+
What are main three types of muscles in our body? What are their structural
and functional specifications?
✓✓ Skeletal, cardiac, smooth
1. Skeletal muscle: Structure: Is multi-nucleated and striated Function: Moves
bones
2. Cardiac muscle: Structure: Is one nucleus, striated, and intercalated discs
Function: Pumps blood
3. Smooth muscle: Structure: Is one nucleus and no striations Function: Performs
various functions such as peristalsis
Draw a diagram to show epimysium, perimysium and endomysium. What
structures do each of them wrap?
✓✓ epimysium surrounds the entire muscle and defines its volume
Perimysium is the connective tissue that wraps bundles of muscle fibers
Each single muscle cell is wrapped individually with a fine layer of loose (areolar)
connective tissue called endomysium
What are sarcomeres? What is their structural organization? How many
types of myofilaments are found in a sarcomere? Which filaments are found
in H-zone, A band and I band. Where are M line and Z line located?
✓✓ A sarcomere is the basic contractile unit of a myocyte (muscle fiber);
sarcomere is the repeating unit of a myofibril in a muscle cell, composed of an
array of overlapping thick and thin filaments between two adjacent Z discs;
sarcomere contains two types of myofilaments: thick and thin filaments; The H-
zone is the region that only contains the thick filaments, the I-band only contains
the thin filaments, the A-band contains the thick-filaments in their entirety; (see
image)
Where is motor end plate located? Know the events and their significance
starting from arrival of action potential to the action terminal and muscle
contraction. Where are Ach stored, AChE located and their function?
, 2
Expert solutions
✓✓ The motor endplate is immediately across the synaptic cleft from the
presynaptic axon terminal; Acetylcholine is stored in vesicles at the ends of
cholinergic (acetylcholine-producing) neurons. Acetylcholinesterase (AChE) is a
cholinergic enzyme primarily found at postsynaptic neuromuscular junctions,
especially in muscles and nerves and its fuction is to breaks down ACh into
acetate and choline, products that cannot activate the ACh receptor.
Do you know that muscle fibers and neurons cannot divide (by mitosis)
and regenerated? Know the function of satellite cells associated with muscle
fibers.
✓✓ Satellite cells remain in the adult and can replace damaged muscle fibers to
some degree
What are troponin, tropomyosin, actin, myosin and dystrophin? Where are
they found and what functions do they perform?
✓✓ troponin- found when heart muscles become damaged,
Tropomyosin- (skeletal muscles) binds along actin filaments and regulates actin-
myosin interaction in muscle and nonmuscle cells,
actin- a protein that is an important contributor to the contractile property of
muscle, (every muscle tissue)
myosin- a protein that converts chemical energy in the form of ATP to
mechanical energy, (every muscle tissue)
and dystrophin- part of a group of proteins (a protein complex) that work together
to strengthen muscle fibers and protect them from injury as muscles contract and
relax (found in skeletal and cardiac muscles) .
What leads to sarcomere shortening and what happens during shortening?
How a cross bridge is formed and when ATP is required?
✓✓ Once the myosin-binding sites are exposed, and if sufficient ATP is present,
myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens
and the muscle contracts; ATP must bind to myosin to break the cross-bridge and
enable the myosin to rebind to actin at the next muscle contraction
What are the sources of ATP formation? Which process will sustain ATP
supply for few seconds, minute and long duration? Such as anaerobic
cellular respiration can provide ATP supply for 1 minute.
Expert solutions
bio 2301 exam #3 Questions and Answers
(100% Correct Answers) Already Graded A+
What are main three types of muscles in our body? What are their structural
and functional specifications?
✓✓ Skeletal, cardiac, smooth
1. Skeletal muscle: Structure: Is multi-nucleated and striated Function: Moves
bones
2. Cardiac muscle: Structure: Is one nucleus, striated, and intercalated discs
Function: Pumps blood
3. Smooth muscle: Structure: Is one nucleus and no striations Function: Performs
various functions such as peristalsis
Draw a diagram to show epimysium, perimysium and endomysium. What
structures do each of them wrap?
✓✓ epimysium surrounds the entire muscle and defines its volume
Perimysium is the connective tissue that wraps bundles of muscle fibers
Each single muscle cell is wrapped individually with a fine layer of loose (areolar)
connective tissue called endomysium
What are sarcomeres? What is their structural organization? How many
types of myofilaments are found in a sarcomere? Which filaments are found
in H-zone, A band and I band. Where are M line and Z line located?
✓✓ A sarcomere is the basic contractile unit of a myocyte (muscle fiber);
sarcomere is the repeating unit of a myofibril in a muscle cell, composed of an
array of overlapping thick and thin filaments between two adjacent Z discs;
sarcomere contains two types of myofilaments: thick and thin filaments; The H-
zone is the region that only contains the thick filaments, the I-band only contains
the thin filaments, the A-band contains the thick-filaments in their entirety; (see
image)
Where is motor end plate located? Know the events and their significance
starting from arrival of action potential to the action terminal and muscle
contraction. Where are Ach stored, AChE located and their function?
, 2
Expert solutions
✓✓ The motor endplate is immediately across the synaptic cleft from the
presynaptic axon terminal; Acetylcholine is stored in vesicles at the ends of
cholinergic (acetylcholine-producing) neurons. Acetylcholinesterase (AChE) is a
cholinergic enzyme primarily found at postsynaptic neuromuscular junctions,
especially in muscles and nerves and its fuction is to breaks down ACh into
acetate and choline, products that cannot activate the ACh receptor.
Do you know that muscle fibers and neurons cannot divide (by mitosis)
and regenerated? Know the function of satellite cells associated with muscle
fibers.
✓✓ Satellite cells remain in the adult and can replace damaged muscle fibers to
some degree
What are troponin, tropomyosin, actin, myosin and dystrophin? Where are
they found and what functions do they perform?
✓✓ troponin- found when heart muscles become damaged,
Tropomyosin- (skeletal muscles) binds along actin filaments and regulates actin-
myosin interaction in muscle and nonmuscle cells,
actin- a protein that is an important contributor to the contractile property of
muscle, (every muscle tissue)
myosin- a protein that converts chemical energy in the form of ATP to
mechanical energy, (every muscle tissue)
and dystrophin- part of a group of proteins (a protein complex) that work together
to strengthen muscle fibers and protect them from injury as muscles contract and
relax (found in skeletal and cardiac muscles) .
What leads to sarcomere shortening and what happens during shortening?
How a cross bridge is formed and when ATP is required?
✓✓ Once the myosin-binding sites are exposed, and if sufficient ATP is present,
myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens
and the muscle contracts; ATP must bind to myosin to break the cross-bridge and
enable the myosin to rebind to actin at the next muscle contraction
What are the sources of ATP formation? Which process will sustain ATP
supply for few seconds, minute and long duration? Such as anaerobic
cellular respiration can provide ATP supply for 1 minute.
