bio 2301 exam #3 UPDATED ACTUAL
Exam Questions and CORRECT Answers
What are main three types of muscles in our body? What are their structural and functional
specifications? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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. - CORRECT ANSWER -
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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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. - CORRECT ANSWER - Human body uses three types of molecules
to yield the necessary energy to drive ATP synthesis: fats, proteins, and carbohydrates; ATP
phosphocreatine system- few seonds, Anaerobic Glycolysis system- 1 min, Aerobic System-
longest duration
Exam Questions and CORRECT Answers
What are main three types of muscles in our body? What are their structural and functional
specifications? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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. - CORRECT ANSWER -
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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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. - CORRECT ANSWER - Human body uses three types of molecules
to yield the necessary energy to drive ATP synthesis: fats, proteins, and carbohydrates; ATP
phosphocreatine system- few seonds, Anaerobic Glycolysis system- 1 min, Aerobic System-
longest duration
