BIOL 2500 Exam 3 - Dr. Ferdous - Auburn
University Exam Study Guide
Z line (disc) - ANSWER Anchor for thin filaments
M line - ANSWER Anchor for thick filaments
A band - ANSWER Dark area; extends length of the thick filaments
I band - ANSWER Light area; thin myofilaments only (Z disc is center of this)
H zone - ANSWER Thick myofilaments only (M line is center of this)
Sacromere - ANSWER Functional unit of skeletal muscle; Z disc to Z disc;
aligned end to end within myofibril
Myosin
(~300 myosin molecules per thick myofilament) - ANSWER Makes up thick
myofilaments
1) Myosin
2-3) Actin & ATP - ANSWER __1__ has a rodlike tail and two globular heads that
contain binding sites for __2__ and __3__.
Nerve - ANSWER In order to receive a signal to contract, each skeletal muscle
must be served by a ______.
Actin - ANSWER Makes up thin myofilaments
1) G-actin
2) Myosin heads - ANSWER Actin is made of ___1___, which contain binding sites
for ___2___
Tropomyosin - ANSWER Rod shaped protein that runs along actin in thin
myofilaments; blocks myosin-binding sites on actin when muscle relaxed
Troponin - ANSWER Three polypeptide subunit complex in thin myofilaments
- 1 subunit bound to actin
- 1 subunit bound to tropomyosin
- 1 subunit binds Ca2+ - ANSWER What does each of the three polypeptide
subunit complexes of troponin do?
,1) Sarcoplasmic Reticulum
2) Ca - ANSWER ____1____ stores and regulates intracellular __2__ that is
necessary for contraction
Sarcoplasmic Reticulum - ANSWER Interconnecting longitudinally running
tubules that surround each myofibril.
Terminal Cisternae - ANSWER Two larger tubules that run perpendicular to
myofibril at junction of A band and I band
Mitochondria & Glycosomes - ANSWER ______ & _____ provide energy for
contraction of SR.
T-tubules (transverse tubules) - ANSWER Invaginations of sarcolemma; found at
each A band/I band junction; elongated tubes
Triad - ANSWER T tubule and two terminal cisternae
Calcium - ANSWER When electrical impulses are transmitted what is released?
1) Triads
2) Ca - ANSWER __1__ are responsible for contraction of myofibrils, and also
stimulate adjacent terminal cisternae to release __2__needed for muscle
contraction.
Triads - ANSWER What allows electrical impulses to be transmitted deep into
muscle fiber and to every sarcomere?
Voltage Sensors - ANSWER Integral proteins protruding from t-tubule into space
between t-tubule and terminal cisternae act as ___________
1) Thin filaments slide past thick
filaments
2) The I-bands shorten
3) Sarcomeres shorten
4) H-zones disappear
5) A-bands move closer together
but length is same - ANSWER What 5 things happen in the sliding filament model
of contraction?
Nervous system & Muscular system - ANSWER It takes both the _______ and the
_______ for muscle contraction to occur.
NMJ (neuromuscular junction) - ANSWER Each muscle fiber has a single ______
, Neuromuscular junction - ANSWER Where axon terminal meets a muscle fiber
Binding of acetylcholine to membrane receptors - ANSWER At the
neuromuscular junction, the muscle contraction initiation event is
____________________.
Axon terminal - ANSWER End of neuron that communicates with target cell
Synaptic vesicles - ANSWER Site that releases acetylcholine (ACh)
Synaptic Cleft - ANSWER Space between axon terminal and sarcolemma
Motor end plate - ANSWER Specialized area of muscle fiber that synapses with
axon terminal or makes contact with axon terminal
Junctional folds - ANSWER Folds IN SARCOLEMMA at motor end plate that
contain acetylcholine receptors
Voltage gated channels - ANSWER Open when membrane potential changes
Chemically (Ligand) gated channels - ANSWER Open when a chemical binds
Mechanically gated channels - ANSWER Open in response to mechanical
movement
Membrane Potential - ANSWER Difference in electrical charge across plasma
membrane
Negative
(~ -70 mV ... actual voltage difference varies from -40 mV to -90 mv) - ANSWER In
resting membrane potential, inside of cell has overall ______ charge relative to
outside.
1) Excitable
2) Stimuli - ANSWER Muscle & Nerve cells are ___1___,
meaning they can receive and respond to ___2___.
YES!!! - ANSWER Can resting membrane potential change?
Motor end plate - ANSWER __________ is axon terminal that is touching the
sarcolemma
Depolarization - ANSWER Membrane potential becomes LESS negative than the
resting membrane potential
University Exam Study Guide
Z line (disc) - ANSWER Anchor for thin filaments
M line - ANSWER Anchor for thick filaments
A band - ANSWER Dark area; extends length of the thick filaments
I band - ANSWER Light area; thin myofilaments only (Z disc is center of this)
H zone - ANSWER Thick myofilaments only (M line is center of this)
Sacromere - ANSWER Functional unit of skeletal muscle; Z disc to Z disc;
aligned end to end within myofibril
Myosin
(~300 myosin molecules per thick myofilament) - ANSWER Makes up thick
myofilaments
1) Myosin
2-3) Actin & ATP - ANSWER __1__ has a rodlike tail and two globular heads that
contain binding sites for __2__ and __3__.
Nerve - ANSWER In order to receive a signal to contract, each skeletal muscle
must be served by a ______.
Actin - ANSWER Makes up thin myofilaments
1) G-actin
2) Myosin heads - ANSWER Actin is made of ___1___, which contain binding sites
for ___2___
Tropomyosin - ANSWER Rod shaped protein that runs along actin in thin
myofilaments; blocks myosin-binding sites on actin when muscle relaxed
Troponin - ANSWER Three polypeptide subunit complex in thin myofilaments
- 1 subunit bound to actin
- 1 subunit bound to tropomyosin
- 1 subunit binds Ca2+ - ANSWER What does each of the three polypeptide
subunit complexes of troponin do?
,1) Sarcoplasmic Reticulum
2) Ca - ANSWER ____1____ stores and regulates intracellular __2__ that is
necessary for contraction
Sarcoplasmic Reticulum - ANSWER Interconnecting longitudinally running
tubules that surround each myofibril.
Terminal Cisternae - ANSWER Two larger tubules that run perpendicular to
myofibril at junction of A band and I band
Mitochondria & Glycosomes - ANSWER ______ & _____ provide energy for
contraction of SR.
T-tubules (transverse tubules) - ANSWER Invaginations of sarcolemma; found at
each A band/I band junction; elongated tubes
Triad - ANSWER T tubule and two terminal cisternae
Calcium - ANSWER When electrical impulses are transmitted what is released?
1) Triads
2) Ca - ANSWER __1__ are responsible for contraction of myofibrils, and also
stimulate adjacent terminal cisternae to release __2__needed for muscle
contraction.
Triads - ANSWER What allows electrical impulses to be transmitted deep into
muscle fiber and to every sarcomere?
Voltage Sensors - ANSWER Integral proteins protruding from t-tubule into space
between t-tubule and terminal cisternae act as ___________
1) Thin filaments slide past thick
filaments
2) The I-bands shorten
3) Sarcomeres shorten
4) H-zones disappear
5) A-bands move closer together
but length is same - ANSWER What 5 things happen in the sliding filament model
of contraction?
Nervous system & Muscular system - ANSWER It takes both the _______ and the
_______ for muscle contraction to occur.
NMJ (neuromuscular junction) - ANSWER Each muscle fiber has a single ______
, Neuromuscular junction - ANSWER Where axon terminal meets a muscle fiber
Binding of acetylcholine to membrane receptors - ANSWER At the
neuromuscular junction, the muscle contraction initiation event is
____________________.
Axon terminal - ANSWER End of neuron that communicates with target cell
Synaptic vesicles - ANSWER Site that releases acetylcholine (ACh)
Synaptic Cleft - ANSWER Space between axon terminal and sarcolemma
Motor end plate - ANSWER Specialized area of muscle fiber that synapses with
axon terminal or makes contact with axon terminal
Junctional folds - ANSWER Folds IN SARCOLEMMA at motor end plate that
contain acetylcholine receptors
Voltage gated channels - ANSWER Open when membrane potential changes
Chemically (Ligand) gated channels - ANSWER Open when a chemical binds
Mechanically gated channels - ANSWER Open in response to mechanical
movement
Membrane Potential - ANSWER Difference in electrical charge across plasma
membrane
Negative
(~ -70 mV ... actual voltage difference varies from -40 mV to -90 mv) - ANSWER In
resting membrane potential, inside of cell has overall ______ charge relative to
outside.
1) Excitable
2) Stimuli - ANSWER Muscle & Nerve cells are ___1___,
meaning they can receive and respond to ___2___.
YES!!! - ANSWER Can resting membrane potential change?
Motor end plate - ANSWER __________ is axon terminal that is touching the
sarcolemma
Depolarization - ANSWER Membrane potential becomes LESS negative than the
resting membrane potential
