BIO 201 EXAM 3
• Muscles can stretch as much as times contracted length.: Three
(3)
• What is elasticity?: Returns to original length after being stretched.
• What is skeletal muscle?: VOLUNTARY STRIATED muscle that is usuallyattached to
one or more bones.
• Is skeletal muscle voluntary?: Yes!
• What is voluntary?: Subject to conscious control
• What are striations?: Skeletal muscle exhibits light and dark transverse bands.
• What is the cause of striations?: The overlapping arrangement of their internalcontractile
proteins.
• What is involuntary?: Not under conscious control and is never attached tobone.
• What are other names for skeletal muscles?: 1. Muscle fibers
2. Myofibers
• What are the three connective tissues in skeletal muscle?: 1. Endomysium
2. Perimysium
3. Epimysium
• Collagen is not & .: Excitable & Contractile
• Collagen is somewhat & .: Extensible and Elastic
• What is the sarcolemma?: Plasma membrane of the muscle fiber.
• What is the sarcoplasm?: Cytoplasm of the muscle fiber.
• What are myofibrils?: Long protein bundles that occupies main portion ofsarcoplasm.
• What two things are stored in myofibrils and what are their functions?: 1.Glycogen -
provides energy during heightened exercise.
2. Myoglobin - red pigment that stores oxygen until needed for muscular activity.
• Muscle fibers have multiple nuclei pressed up against .: -
Sarcolemma
• What are myoblasts?: Stemm cells that fuse together to form each muscle fiber.
• What are satellite cells?: Unspecialized myoblasts that reman in between themuscle fiber
and endomysium.
, • How is most muscle repair done by?: Fibrosis rather than by regeneration offunctional
muscle.
• True or False, satellite cells can multiply and produce new muscle fibersto some degree?:
True.
• Where are the mitochondria located in a muscle fiber?: Packed into spacesbetween the
myofibrils.
• What is the sarcoplasmic reticulum?: Smooth ER forms a network aroundeach myofibril.
• What does the SR store?: Calcium reservoir - Calcium activates contraction
• What are terminal cisternae?: Dilated sacs on SR which cross muscle fiberfrom one side
to another.
• What are transverse tubules?: Tubular infoldings of the sarcolemma whichpenetrate
through the cell an emerge on the other side.
• What makes up a triad?: A t-tubule and 2 terminal cisterns.
• What are myofilaments?: Myofibrils is a bundle of parallel protein microfila-ments
• What are thick filaments made of?: Made of several hundred molecules of theprotein
myosin.
• What is myosin shaped like?: Golf club
• Describe what how myosin is shaped.: a - 2 chains intertwined to formshaft-like tail
b - double globular head
• What do the heads of myosin form and which directions do they go?: Theheads form an
outward helical array.
One half of the thick filament the head is angled left and the other half of the filamentis angled
right.
• What is the bare zone?: No heads and is located in the middle.
• What is a thin filament made up of?: Composed of two intertwined strands ofa protein
called fibrous (F) actin.
• What does fibrous (F) actin look like?: Beaded necklace.
• What makes up fibrous (F) actin?: String of subunits called globular (G) actin.
• What is on a globular (G) actin?: Active site that binds to the head of myosin.
• What other molecule does a thin filament have?: Tropomyosin
• What does a tropomyosin do?: Each blocks 6 or 7 active sites on the G actinsubunits.
• Muscles can stretch as much as times contracted length.: Three
(3)
• What is elasticity?: Returns to original length after being stretched.
• What is skeletal muscle?: VOLUNTARY STRIATED muscle that is usuallyattached to
one or more bones.
• Is skeletal muscle voluntary?: Yes!
• What is voluntary?: Subject to conscious control
• What are striations?: Skeletal muscle exhibits light and dark transverse bands.
• What is the cause of striations?: The overlapping arrangement of their internalcontractile
proteins.
• What is involuntary?: Not under conscious control and is never attached tobone.
• What are other names for skeletal muscles?: 1. Muscle fibers
2. Myofibers
• What are the three connective tissues in skeletal muscle?: 1. Endomysium
2. Perimysium
3. Epimysium
• Collagen is not & .: Excitable & Contractile
• Collagen is somewhat & .: Extensible and Elastic
• What is the sarcolemma?: Plasma membrane of the muscle fiber.
• What is the sarcoplasm?: Cytoplasm of the muscle fiber.
• What are myofibrils?: Long protein bundles that occupies main portion ofsarcoplasm.
• What two things are stored in myofibrils and what are their functions?: 1.Glycogen -
provides energy during heightened exercise.
2. Myoglobin - red pigment that stores oxygen until needed for muscular activity.
• Muscle fibers have multiple nuclei pressed up against .: -
Sarcolemma
• What are myoblasts?: Stemm cells that fuse together to form each muscle fiber.
• What are satellite cells?: Unspecialized myoblasts that reman in between themuscle fiber
and endomysium.
, • How is most muscle repair done by?: Fibrosis rather than by regeneration offunctional
muscle.
• True or False, satellite cells can multiply and produce new muscle fibersto some degree?:
True.
• Where are the mitochondria located in a muscle fiber?: Packed into spacesbetween the
myofibrils.
• What is the sarcoplasmic reticulum?: Smooth ER forms a network aroundeach myofibril.
• What does the SR store?: Calcium reservoir - Calcium activates contraction
• What are terminal cisternae?: Dilated sacs on SR which cross muscle fiberfrom one side
to another.
• What are transverse tubules?: Tubular infoldings of the sarcolemma whichpenetrate
through the cell an emerge on the other side.
• What makes up a triad?: A t-tubule and 2 terminal cisterns.
• What are myofilaments?: Myofibrils is a bundle of parallel protein microfila-ments
• What are thick filaments made of?: Made of several hundred molecules of theprotein
myosin.
• What is myosin shaped like?: Golf club
• Describe what how myosin is shaped.: a - 2 chains intertwined to formshaft-like tail
b - double globular head
• What do the heads of myosin form and which directions do they go?: Theheads form an
outward helical array.
One half of the thick filament the head is angled left and the other half of the filamentis angled
right.
• What is the bare zone?: No heads and is located in the middle.
• What is a thin filament made up of?: Composed of two intertwined strands ofa protein
called fibrous (F) actin.
• What does fibrous (F) actin look like?: Beaded necklace.
• What makes up fibrous (F) actin?: String of subunits called globular (G) actin.
• What is on a globular (G) actin?: Active site that binds to the head of myosin.
• What other molecule does a thin filament have?: Tropomyosin
• What does a tropomyosin do?: Each blocks 6 or 7 active sites on the G actinsubunits.
