2) Which muscle cells have the greatest ability to regenerate?
D) no muscle can regenerate
9) Calcium ions bind to the ________ molecule in skeletal muscle cells.
10) Myoglobin ________.
A) breaks down glycogen
B) is a protein involved in the direct phosphorylation of ADP
C) stores oxygen in muscle cells
D) produces the end plate potential
11) An elaborate network of membranes in skeletal muscle cells that
functions in calcium storage
is the ________.
A) sarcoplasmic reticulum
C) intermediate filament network
D) myofibrillar network
12) A sarcomere is ________.
A) the nonfunctional unit of skeletal muscle
B) the area between two Z discs
C) the area between two intercalated discs
D) the wavy lines on the cell seen in the microscope
13) Immediately following the arrival of the stimulus at a skeletal
muscle cell there is a short
period called the ________ period during which the events of excitation -contraction coupling
14) Creatine phosphate functions in the muscle cell by ________.
A) forming a temporary chemical compound with myosin
B) forming a chemical compound with actin
C) inducing a conformational change in the myofilaments
D) storing energy that will be transferred to ADP to resynthesize
18) Which of the following are composed of myosin?
A) thick filaments
B) thin filaments
C) all myofilaments
D) Z discs
19) During muscle contraction, myosin cross bridges attach to which active sites?
A) myosin filaments
B) actin filaments
C) Z discs
D) thick filaments
20) Which of the following surrounds the individual muscle cell?
22) Rigor mortis occurs because ________.
A) the cells are dead
B) sodium ions leak out of the muscle
C) no ATP is available to release attached actin and myosin molecules
D) proteins are beginning to break down, thus preventing a flow of
25) The oxygen-binding protein found in muscle cells is ________.
26) The contractile units of skeletal muscles are ________.
C) T tubules
28) One functional unit of a skeletal muscle is ________.
A) a sarcomere
B) a myofilament
C) a myofibril
D) the sarcoplasmic reticulum
33) During vigorous excercise, there may be insufficient oxygen
available to completely break
down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.
A) a strong base
B) stearic acid
C) hydrochloric acid
D) lactic acid
34) When a muscle is unable to respond to stimuli temporarily, it is
in which of the following
A) relaxation period
B) refractory period
C) latent period
D) fatigue period
35) In an isotonic contraction, the muscle ________.
A) changes in length and moves the ʺloadʺ
B) does not change in length but increases tension
C) never converts pyruvate to lactate
D) rapidly resynthesizes creatine phosphate and ATP
36) The muscle cell membrane is called the ________.
38) The mechanism of contraction in smooth muscle is different from
skeletal muscle in that
A) actin and myosin interact by the sliding filament mechanism
B) the trigger for contraction is a rise in intracellular calcium
C) the site of calcium regulation differs
D) ATP energizes the sliding process
41) Which of the following is true about smooth muscle contraction?
A) Certain smooth muscle cells can actually divide to increase their numbers.
B) Smooth muscle, in contrast to skeletal muscle, cannot synthesize
or secrete any
connective tissue elements.
C) Smooth muscle cannot stretch as much as skeletal muscle.
D) Smooth muscle has well-developed T tubules at the site of
42) Smooth muscle is characterized by all of the following except ________.
A) it appears to lack troponin
B) there are more thick filaments than thin filaments
C) there are no sarcomeres
D) there are noncontractile intermediate filaments that attach to
dense bodies within the cell
46) An anaerobic metabolic pathway that results in the production of
two net ATPs per glucose
plus two pyruvic acid molecules is ________.
A) the citric acid cycle
D) the electron transport chain
49) After nervous stimulation stops, ACh in the synaptic cleft is
prevented from continuing
stimulation of contraction by ________.
A) calcium ions returning to the terminal cisternae
B) the tropomyosin blocking the myosin once full contraction is achieved
C) acetylcholinesterase destroying the ACh
D) the action potential stopped going down the overloaded T