FLORIDA INTERNATIONAL UNIVERSITY
Physiology for the Exercise and Sport Sciences
Exam 1 Practice Questions
1. Homeostasis is defined as the
a. ability of human beings to keep body weight within normal limits.
b. maintenance of a constant external temperature inside a room.
c. ingestion of enough food to keep hunger pains from developing.
d. tendency of the body to maintain a stable environment
2. How is oxygen used by living organisms?
a. It controls the amount of heat produced.
b. It is a source of energy.
c. It is used to release energy that is stored in food.
d. It is part of water and is necessary to keep organisms hydrated.
3. A mechanism functioning to maintain a stable internal environment is most likely to involve
a. positive feedback.
b. negative feedback.
c. a vicious circle.
d. none of the above
4. A blood clot stimulating the formation of more blood clotting is an example of
a. positive feedback.
b. negative feedback.
c. homeostasis.
d. a vital sign.
5. Metabolism is defined as the ______.
a. removal of wastes produced by chemical reactions
b. breakdown of substances into simpler forms
c. production of new organisms
d. physical and chemical changes occurring in an organism
6. Homeostatic mechanisms are said to act by negative feedback because changes away from the
normal state
a. stimulate changes to occur in the same direction.
b. inhibit all body reactions.
c. stimulate changes to occur in the opposite direction.
d. stimulate a reduction in all vital needs of the body.
7. A decomposition reaction can be symbolized by
a. A + B  C + D.
b. A + B  AB.
c. AB  A + B.
d. C + D  AB.
8. A solution that contains equal numbers of hydrogen and hydroxyl ions would be called
a. acidic.
b. basic.
c. alkaline.
d. neutral.
9. Electrolytes are substances that
a.
b.
c.
d.
form covalent bonds with water.
ionize when dissolved in water.
cannot conduct electricity in solution.
are not found in the human body in any appreciable amounts
10. The pH scale measure the
a. concentration of hydrogen ions in solution.
b. amounts of salts dissolved in water.
c. number of hydroxyl ions in water.
d. strength of an electrical current carried by a solution.
11. The role played by oxygen in the body is to
a. react with water to form carbonic acid
b. Be used in various metabolic processes
c. help regulate body temperature
d. be used in the release of energy from glucose during respiration
12. The movement of molecules through a membrane by filtration depends upon the presence of
a. osmotic pressure.
b. hydrostatic pressure.
c. atmospheric pressure.
d. none of the above
13. Which of the following processes involves the use of specific carrier molecules?
a. phagocytosis
b. pinocytosis
c. active transport
d. dialysis
14. If the concentration of glucose in the water outside of a cell is higher than the concentration inside,
a. water will tend to enter the cell by osmosis.
b. water will tend to leave the cell by osmosis.
c. glucose will tend to enter the cell by osmosis.
d. glucose will tend to leave the cell by osmosis.
15. The cell membrane functions to
a. maintain the wholeness of the cell.
b. control the entry and exit of various substances.
c. provide a barrier to water-soluble substances.
d. all of the above
16. Which of the following correctly describes the structural arrangement of the cell membrane
a. a solid, rigid layer of phospholipid with loosely bound protein molecules
b. a bilayer of phospholipid molecules in which protein molecules are embedded
c. strong layers of protein molecules where carbohydrate molecules freely float
d. three layers; lipid on the inside, protein in the middle, and carbohydrates (and polysaccharides)
on the outside
17. Molecules bind to receptor sites and are enclosed in vesicles in the process of
a. pinocytosis.
b. phagocytosis.
c. receptor-mediated endocytosis.
d. none of the above
18. Which of the following is not a factor that influences the rate of diffusion?
a.
b.
c.
d.
the distance of diffusion
the concentration of the substance
the amount of energy available for transport molecules
the molecular weight of the diffusing molecules
19. What characteristic is shared by simple diffusion and facilitated diffusion?
a. Both require cellular energy for the transport of substances.
b. Both involve the movement of water across a semipermeable membrane.
c. Both require a special carrier molecule to move substances across the membrane.
d. Both involve the movement of a substance from regions of higher concentration to lower
concentration without cellular energy.
20. What occurs if a red blood cell is placed in a hypotonic solution?
a. The cell will shrink.
b. The cell will swell and may eventually burst.
c. Nothing; the cell will remain the same size and shape.
d. Only permeable substances will leave the cell; otherwise the concentrations within the cell do not
change.
21. A selectively permeable membrane is defined as one that ______
a. allows all substances to pass through
b. allows all organic substances to pass through but excludes all inorganic substances
c. allows some substances to pass through and excludes others
d. is leaky or allows substances to leak through
22. Osmosis is defined as the movement of
a. molecules from a high concentration to a low concentration.
b. water molecules from a high concentration to a low concentration through a selectively permeable
membrane.
c. water molecules from a low concentration to a high concentration through a selectively permeable
membrane.
d. ions from a low pressure region to a high pressure region through a selectively permeable
membrane.
23. Active transport is a physiological process because it ______, whereas diffusion is a physical process
because ______.
a. depends upon life processes and requires cellular energy; it involves nonliving processes and
requires no cellular energy
b. involves physiology changes; molecules are always moving from low to high concentration and
requires no energy
c. pumps molecules from low to high concentration; it moves molecules from high to low
concentration and requires no energy
d. none of the above
24. The relationship of osmotic pressure and the number of solute particles in a solution is the
a. lower the number of solute particles, the greater the osmotic pressure.
b. greater the number of solute particles, the lower the osmotic pressure.
c. greater the osmotic pressure, the lower the number of solute particles.
d. greater the number of solute particles, the greater the osmotic pressure.
25. A hypertonic solution
a. has a greater concentration (number) of solute particles than do the cells in the solution.
b. would cause cells in the solution to lose water or to shrink.
c. has a greater osmotic pressure than do the cells in the solution.
d. all of the above
26. An isotonic solution
a. contains the same concentration of solute particles as a cell.
b. has water entering and leaving a cell in equal amounts.
c. has the same osmotic pressure as the cells in the solution.
d. all of the above
27. A hypotonic solution
a. has a lower concentration (number) of solute particles than do the cells in the solution.
b. would cause cells in the solution to gain water.
c. has a lower osmotic pressure than do the cells in the solution.
d. all of the above
28. Filtration is defined as the movement of molecules through a membrane
a. from low concentration to high concentration.
b. by hydrostatic, or blood, pressure that is greater on one side of the membrane than on the other.
c. From low to high hydrostatic pressure.
d. from low osmotic pressure to high osmotic pressure.
29. Pinocytosis involves ______, whereas phagocytosis involves ______
a. a cell membrane engulfing solid particles; a cell membrane engulfing liquid droplets
b. the expenditure of cellular energy; a physical process with no expenditure of cellular energy
c. a cell membrane engulfing liquid droplets; a cell membrane engulfing solid particles
d. cell eating; cell drinking
30. Membrane connections of adjacent cells allow passage of ions and nutrients from cell to cell are
a. desmosomes
b. tight junctions
c. gap junctions
d. all of the above
31. If a nerve cell has a greater concentration of Na + on the inside and K + on the outside of the cell
membrane, then the movement of Na+ outside and K+ inside is by
a. active transport
b. diffusion.
c. facilitated diffusion
d. all of the above
32. Anabolic metabolism includes
a. substances are synthesized.
b. all processes needed to maintain life.
c. destructive processes by which substances are decomposed.
d. changes of larger molecules into smaller ones.
33. In dehydration synthesis of a carbohydrate
a. Larger molecules are decomposed into smaller ones
b. monosaccharides become joined together
c. water molecules become joined to monosaccharide molecules.
d. he molecule is decomposed into carbon dioxide and water.
34. The reactions of anaerobic respiration occurs in the
a. cytoplasm.
b. mitochondria
c. nucleus
d. all of the above
35. Which of the following substances increases in amount during cellular respiration?
a.
b.
c.
d.
oxygen
glucose
ATP
Glycogen
36. Which of the following is an example of catabolism
a. the synthesis of the cell membrane from precursor molecules
b. the oxidation of glucose in the cytoplasm and mitochondria
c. the formation of secretory proteins in the pancreas
d. the duplication of DNA molecules in the nucleus
37. Which of the following is NOT a characteristic of enzymes?
a. They speed up the rate of chemical reactions but are not used up in the process.
b. They are all proteins.
c. They are most active at low temperatures around 53 degrees C.
d. They have active sites and act on specific substances called substrates.
38. What is the function of ADP molecules in living cells?
a. They form a genetic material important for reproduction.
b. They act to "capture" energy from the oxidation of fuels to be used in other cell processes.
c. They act as coenzymes so that fats can be synthesized.
d. They are an integral part of the cell membrane, important in the transport of water molecules.
39. An important mechanism by which metabolic pathways are controlled under physiological conditions
is
a. negative feedback.
b. positive feedback.
c. substrate concentration.
d. genetic control.
40. A glucose molecule is changed into two pyruvic acid molecules in
a. glycolysis.
b. the citric acid cycle.
c. the electron transport system.
d. none of the above
41. An example of an anabolic metabolism reaction is
a. monosaccharides + monosaccharides  glycogen + H2O
b. dipeptide  amino acid + amino acid
c. glycerol + 3 fatty acid molecules  3H2O + fat molecules
d. glycogen  many monosaccharides
42. Dehydration synthesis reactions involve ______, whereas hydrolysis reactions involve ______.
a. loss of H2O to form bonds; influx of H2O to break bonds
b. breaking large molecules into smaller ones; building large molecules from smaller ones
c. forming H2O by joining H and O atoms; breaking H2O molecules apart
d. loss of energy; gain of energy
43. An enzyme can be defined as a
a. protein that is produced from a chemical reaction.
b. metabolic reactions.
c. protein that promotes metabolic reactions.
d. structural protein that is important for the structure of cells.
44. Three factors that increase the rates of enzyme-controlled reactions are the
a. number of enzyme molecules, number of substrate molecules, and efficiency of the enzyme.
b. temperature of the reaction, number of H2O molecules involved, and strength of bonds being
formed.
c. number of enzyme molecules formed, number of substrate molecules formed, and strength of the
enzyme.
d. none of the above
45. Anaerobic respiration involves chemical reactions in ______, whereas aerobic respiration involves
reactions in _______.
a. mitochondria; cytoplasm with O2 needed
b. cytoplasm without O2 needed; cytoplasm with CO2 required
c. mitochondria without O2 needed; mitochondria with O2 needed
d. cytoplasm without O2 needed; mitochondria with O2 needed
46. Which of the following is true regarding aerobic respiration?
a. It occurs in cytoplasm.
b. Oxygen must be available.
c. Less energy is transferred to form ATP than in anaerobic respiration.
d. none of the above
47. The importance of ATP molecules to cellular processes is that it
a. is formed by muscles contracting or whenever cellular work occurs.
b. provides energy for cellular work when the terminal, high-energy bond is broken.
c. is an active solute in all synthesis reactions such as synthesis of proteins.
d. is a by-product of all decomposition reactions such as glycogen breaking down to glucose.
48. Myofibrils are composed primarily of
a. actin and myosin.
b. ATP and ADP.
c. Troponin.
d. tropomyosin.
49. Neurotransmitters are stored in vesicles within
a. myofibrils.
b. motor units.
c. motor end plate.
d. motor neuron endings.
50. The enzyme cholinesterase causes acetylcholine to
a. bond to actin.
b. be secreted from the motor end plate.
c. decompose.
d. form cross-bridges.
51. Creatine phosphate serves to
a. cause the decomposition of ATP.
b. cause the decomposition of ADP.
c. supply energy for the synthesis of ATP.
d. supply energy for the change of ATP to ADP.
52. The all-or-none response means that
a. all of the muscles in a region contract together.
b. all of the muscle fibers within a muscle contract together.
c. when a muscle fiber contracts, it contracts completely.
d. when a muscle fiber contracts, all of its ATP is changed to ADP.
53. Multiunit smooth muscle
a. is composed of sheets of muscle cells.
b. tends to display rhythmicity.
c. occurs in the walls of the stomach and intestines.
d. none of the above
54. At the neuromuscular junction, the muscle fiber membrane is folded to form a
a. motor neuron.
b. neurotransmitter.
c. motor unit.
d. motor end plate.
55. The striated appearance of skeletal muscle results from the
a. transverse tubule pattern.
b. sarcoplasmic reticulum network.
c. sarcomere arrangement.
d. cisternae placement.
56. What is the function of the transverse tubules?
a. the storage of sodium ions for the action potential at the cell surface
b. to transmit a muscle impulses into the cell interior
c. the storage of calcium ions
d. the place where actin and myosin interact
57. Which of the following is not true when comparing red and white muscle types?
a. Red muscles contract more slowly than white.
b. Red muscles contain more myoglobin than white.
c. Red muscles have fewer mitochondria than white.
d. Red muscles fatigue more slowly than white.
58. Rigor mortis that occurs in skeletal muscles a few hours after death is due to
a. excessive ATP and decreased permeability to calcium.
b. a decrease of ATP and increased permeability to calcium.
c. excessive ATP.
d. none of the above
59. In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the
muscle responds is called the
a. refractory period.
b. relaxation period.
c. latent period.
d. contraction period.
60. The very brief moment following stimulation when a muscle remains unresponsive to additional
stimulation is called the
a. refractory period.
b. relaxation period.
c. latent period.
d. contraction period.
61. Activities such as long duration swimming and running are most likely to stimulate development of
a. slow, white muscle fibers.
b. fast, white muscle fibers.
c. slow, red muscle fibers.
d. fast, red muscle fibers.
62. A neuromuscular junction can be described as
a. being composed of a junction between a motor neuron and a muscle fiber
b. a site where there is actually a gap, or cleft, between the neuron and muscle
c. a site where neurotransmitters are released into the synaptic cleft from the motor neuron
d. all of the above
63. The first event in muscle fiber contraction is that
a. the muscle fiber membrane is stimulated and a muscle impulse travels deep into the fiber through
transverse tubules.
b. acetylcholine diffuses across a gap at a neuromuscular junction.
c. stimulation occurs when acetylcholine is released from the end of the motor neuron.
d. calcium ions diffuse from sarcoplasmic reticulum into the sarcoplasm and bind to troponin
molecules.
64. Which of the following major events in muscle contraction are stated properly?
a. Tropomyosin molecules move and expose specific sites on myosin filaments
b. Actin filaments slide inward along myosin filaments.
c. Cross-bridges form between actin and sarcolemma filaments.
d. All of the above.
65. ATP is related to creatine phosphate by
a. ATP supplying energy to synthesize creatine phosphate from creatine and phosphate.
b. creatine phosphate supplying energy to regenerate ATP from ADP and phosphate
c. both having three phosphate groups.
d. both being required to stimulate a muscle to contract.
66. A motor unit is defined as
a. many myofibrils within a sarcolemma.
b. many motor end plates within a neuromuscular junction.
c. a motor neuron and the muscle fibers associated with it.
d. the functional unit of a muscle fiber.
67. The role of ATP in muscle contraction is to supply energy for
a. creatine phosphate synthesis.
b. glycogen synthesis.
c. cellular respiration.
d. myofilament movement.
68. Threshold stimulus is defined as the
a. maximum stimulus required to cause a muscle contraction.
b. amount of acetylcholine required to cause a muscle to contract.
c. minimal stimulus needed to elicit a muscular contraction.
d. The minimal strength of stimulation needed to elicit a muscle contraction is called the threshold
stimulus.
69. Oxygen debt in muscles may develop because of
a. the inability of respiratory and circulatory systems to supply enough oxygen to skeletal muscles
when used strenuously for a minute or two.
b. the inability of myoglobin molecules to store enough oxygen when skeletal muscles are used
strenuously for a minute or two.
c. too much oxygen used in forming pyruvic acid when skeletal muscles are contracted strenuously
for a minute or two.
d. too many mitochondria utilizing oxygen to synthesize ATP when skeletal muscles are contracted
for a minute or two.
70. During muscle contraction, calcium ions combine with __________, and this exposes active sites for
cross-bridge formation.
a. tropomyosin
b. troponin
c. myosin
d. G-actin
71. Liver cells convert lactic acid to _________
a. ATP.
b. Pyruvic acid
c. Ketones
d. none of the above
72. The smallest living units capable of carrying out their own basic life functions are called
__________.
A) organs
B) organ systems
C) tissues
D) cells
E) organelles
73. Referring to a membrane as "selectively permeable" describes its ability to __________.
A) restrict the movement of particular ions across a membrane
B) restrict only the movement of sodium across a membrane
C) provide a barrier that restricts the movement of all ions across a membrane
D) provide a minimal barrier that allows almost any ion to move across a membrane
E) restrict only the movement of potassium across the membrane
74. Homeostasis is a term which describes the process whereby the body __________.
A) affects the external environment
B) maintains a constant external environment
C) maintains a constant internal environment
D) maintains a variable internal environment
E) maintains a constant internal and external environment
75. Which of the following statements is NOT accurate descriptions of the homeostatic mechanisms
of the body?
A) They function through either negative or positive feedback systems.
B) They maintain each regulated variable around a set point.
C) They respond to changes in the external environment.
D) They maintain a constant internal environment in the face of a variable external environment.
E) They have an unlimited capacity to respond to changes in the external environment.
76. Changes in the external environment alter the __________, which is detected by the
__________, and that information is sent to the integrator.
A) set point regulated variable
B) regulated variable set point
C) error signal regulated variable
D) sensor regulated variable
E) regulated variable sensor
77. The __________ determines the extent of the error signal in a feedback loop, in order to initiate
the appropriate response.
A) sensor
B) integrator
C) effector
D) set point
E) regulated variable
78. In a negative feedback loop, __________.
A) a decrease in the regulated variable from set point will cause a decrease in effector output
B) an increase in the regulated variable from set point will cause an increase in effector output
C) an increase in the regulated variable from set point will cause a decrease in effector output
D) the direction of change in the error signal is always negative
E) the direction of change in the error signal is always positive
79. In a feedback loop, the integrator __________.
A) determines whether the regulated variable has changed from set point
B) detects a change in the regulated variable
C) directly alters the regulated variable in an attempt to return to set point
D) arbitrarily determines the output to the effector without referring to the set point
E) does not involve the error signal in determining the response of the effector organ
80. In a positive feedback loop, __________.
A) a decrease in the regulated variable from set point will cause an increase in effector output
B) an increase in the regulated variable from set point will cause an increase in effector output
C) an increase in the regulated variable from set point will cause a decrease in effector output
D) the direction of change in the error signal is always negative
E) the direction of change in the error signal is always positive
81. The __________ acts as the integrator for the thermoregulatory system.
A) hypothalamus
B) medulla
C) pons
D) cerebrum
E) pituitary gland
82. Exercise provides a substantial stressor to many systems of the body, including the
cardiovascular system, forcing the body to __________.
A) distribute resources in an unorganized manner
B) prioritize system resources exclusively to the brain
C) distribute resources to active skeletal muscle only
D) prioritize resource allocation
E) prioritize system resources, putting skeletal muscle at the top of the list
83. In order to continue to progress in response to training, an athlete must __________.
A) continue to train at the same intensity
B) progressively increase training intensity
C) be sure to overdo it as often as possible
D) reduce the time allowed for recovery
E) decrease training intensity
84. __________ are lipid molecules composed of a glycerol and three fatty acids.
A) Phospholipids
B) Saturated fatty acids
C) Eicosanoids
D) Steroids
E) Triglycerides
85. What is the difference between a saturated and an unsaturated fatty acid?
A) Unsaturated are heavier than saturated, even though they have the same number of carbons.
B) Saturated fatty acids have at least one double bond between carbons.
C) Unsaturated fatty acids have at least one double bond between carbons.
D) Unsaturated fatty acids have more hydrogen molecules.
E) Saturated fatty acids have a longer carbon chain.
86. __________ are lipids that form the core structure of cell membranes and micelles.
A) Phospholipids
B) Saturated fatty acids
C) Triglycerides
D) Steroids
E) Eicosanoids
87. __________ act(s) as the precursor to steroid molecules, many of which function as hormones.
A) Cholesterol
B) Saturated fatty acids
C) Unsaturated fatty acids
D) Eicosanoids
E) Phospholipids
88. __________ are molecules whose general structure includes a carboxyl group, an amine group,
a hydrogen molecule, and a residual group.
A) Lipids
B) Nucleotides
C) Proteins
D) Amino acids
E) Carbohydrates
89. Peptide bonds that link amino acids in a chain are formed by a __________ reaction.
A) phosphorylation
B) condensation
C) dehydration
D) hydration
E) dehydrogenation
90.The __________ structure of a protein is created by hydrogen bonds between the hydrogen atom
on the amine group and the oxygen atom on the carboxyl group.
A) primary
B) secondary
C) tertiary
D) quaternary
E) quintary
91. Which of the following is NOT an example of globular protein?
A) growth hormone
B) myoglobin
C) hemoglobin
D) Na+/K+ pumps
E) collagen
92. __________ is a molecule that is composed of both fibrous and globular proteins.
A) A Na+/K+ pump
B) Myoglobin
C) Myosin
D) Actin
E) Collagen
93. __________ are molecules that are composed of one or more phosphate groups, a 5-carbon
sugar, and a nitrogenous base.
A) Lipids
B) Phospholipids
C) Nucleotides
D) Amino acids
E) Glycoproteins
94. The presence of __________ in the plasma membrane can reduce the fluidity of the membrane.
A) cholesterol
B) integral membrane proteins
C) peripheral membrane proteins
D) glycoproteins
E) phospholipids
95. These molecules span the membrane multiple times and cannot be easily removed without
disrupting the membrane. They can also function as channels that allow ions to permeate the
membrane.
A) phospholipids
B) cholesterol
C) glycoproteins
D) peripheral membrane proteins
E) integral membrane proteins
96. __________ function(s) in the recognition of cells; they label the cell as part of the body.
A) Integral membrane proteins
B) Peripheral membrane proteins
C) Glycoproteins
D) Cholesterol
E) Phospholipids
97. The __________ is the site of ribosomal RNA production.
A) nucleus
B) nucleolus
C) mitochondria
D) cytosol
E) lysosome
98. Genetic material and other signals transmitted to and from the nucleus must pass through
__________.
A) the nuclear envelope
B) the nuclear transport proteins
C) the nucleolus
D) the nuclear pore
E) vaults
99. Molecules that are to be released by cells are stored in membrane-bound structures called
__________.
A) secretory vesicles
B) inclusions
C) the Golgi apparatus
D) excretory vesicles
E) the endoplasmic reticulum
100.
Continuous with the outer portion of the nuclear pore, this membrane-bound structure
functions in the synthesis of secretory proteins, integral membrane proteins, or proteins
bound for other organelles.
A) rough endoplasmic reticulum
B) smooth endoplasmic reticulum
C) mitochondria
D) lysosome
E) nucleolus
101.
The __________ is the site where lipids, triglycerides, and steroids are synthesized, as well
as where calcium is stored within the cell.
A) rough endoplasmic reticulum
B) smooth endoplasmic reticulum
C) mitochondria
D) lysosome
E) nucleolus
102.
The __________ is the organelle which provides further processing of proteins to prepare
them for transport to their final destination within the cell.
A) peroxisome
B) mitochondria
C) smooth endoplasmic reticulum
D) lysosome
E) Golgi apparatus
103.
The inner membrane of the mitochondria houses enzymes and other molecules directly
involved in __________.
A) glycolysis
B) electron transport
C) replication
D) muscle contraction
E) protein synthesis
104.
__________ are membrane-bound organelles containing enzymes that degrade cellular and
extracellular debris.
A) Lysosomes
B) Mitochondria
C) Peroxisomes
D) Ribosomes
E) Vaults
105.
__________ are organelles not bound by membranes that are involved in the synthesis of
proteins, and are found in two separate subunits (a small and large form) when not active.
A) Peroxisomes
B) Lysosomes
C) Vaults
D) Ribosomes
E) Centrioles
106.
__________ are proteins that form channels between cells, allowing ions and small
molecules to diffuse directly from one cell to the other.
A) Connexins B) Cadherins C) Dyneins D) Occludins E) Tubulins
107.
In some cases, signals originating within one cell can diffuse directly to a neighboring cell
through __________.
A) desmosomes
B) cadherins
C) gap junctions
D) tight junctions
E) occludins
108.
The nonspecific process whereby small molecules are moved into the cell through
indentation and pinching of the outer edge of the cell membrane is called __________.
A) endocytosis
B) pinocytosis
C) exocytosis
D) phagocytosis
E) receptor-mediated endocytosis
109.
Amoeboidlike movement of the plasma membrane as it extends to engulf a particle in the
extracellular fluid describes the process of __________.
A) endocytosis
B) pinocytosis
C) exocytosis
D) phagocytosis
E) receptor-mediated endocytosis
110.
Intercellular communication can occur through the binding of a chemical released from one
cell to a specific ___________ on another cell.
A) receptor
B) organelle
C) nucleus
D) clathrin-coated vesicle
E) phagosome
111.
A) A
112.
A) A
In the chemical equation A + B  C + D, which of the chemicals would be termed the
reactant(s)?
B) B
C) A and B
D) C and D
E) C
In the chemical equation A + B  C + D, which of the chemicals would be termed the
product(s)?
B) B
C) A and B
D) C and D
E) C
113.
The sum of the thousands of chemical reactions that occur within the body is called
__________.
A) metabolism
B) hydrolysis
C) phosphorylation
D) oxidation
E) reduction
114.
Chemical reactions that involve splitting a water molecule, thereby causing the peptide bonds
that link amino acids together to break, are called __________ reactions.
A) hydrolysis
B) phosphorylation
C) condensation
D) oxidation
E) reduction
115.
Chemical reactions that involve the formation of peptide bonds between amino acids that
produce water as a byproduct are called __________ reactions.
A) hydrolysis
B) phosphorylation
C) condensation
D) oxidation
E) reduction
116.
Chemical reactions that involve the production of a phosphate bond are called __________
reactions.
A) condensation
B) phosphorylation
C) dephosphorylation
D) oxidation
E) reduction
117.
Chemical reactions that involve the breaking of a phosphate bond are called __________
reactions.
A) condensation
B) phosphorylation
C) dephosphorylation
D) oxidation
E) reduction
118.
Oxidation reactions are broadly defined by the involvement of oxygen because __________.
A) oxygen gives away its electrons very readily
B) oxygen holds on to its electrons
C) oxygen is always involved in oxidation reactions
D) oxygen has many electrons to give away
E) oxygen tends to pull electrons from other molecules as bonds are formed
119.
Energy cannot be created or destroyed, but can ONLY __________.
A) change form
B) drive chemical reactions
C) be observed as the byproduct heat
D) be converted into mechanical energy
E) be used to drive the next reaction
120.
In a reaction, the addition of an excess of products will cause the reaction to proceed in which
direction (in the absence of end-product inhibition)?
A) toward the product
B) toward the reactant
C) toward equilibrium
D) excess product will not alter the reaction direction
E) forward direction
121.
Molecules must have sufficient potential energy to overcome the __________ and, thereby,
allow the reaction to proceed.
A) transformation state
B) mass action
C) transition state
D) activation energy barrier
E) kinetic energy
122.
Decreasing temperatures will __________ the frequency of collisions between molecules,
thereby __________ the reaction rate.
A) increase decreasing
B) decrease decreasing
C) not alter not changing
D) increase increasing
E) not alter increasing
123.
Enzymes act as __________ to increase reaction rates.
A) an energy source
B) reactants
C) products
D) catalysts
E) intermediates
124.
The first step in a reaction that involves an enzyme is the __________.
A) catalytic step
B) product step
C) collision of products
D) formation of an enzyme-substrate complex
E) collision of reactants
125.
Once an enzyme has been through the catalytic step of a reaction and the product has been
released, it __________.
A) is no longer able to bind to another substrate
B) will go on to bind to another reactant
C) will reverse the reaction, producing more reactant from product
D) will be degraded by other enzymes
E) is irreversibly bound to that product
126.
Enzymes can ONLY affect __________.
A) reaction rates
B) the direction of a reaction
C) the amount of energy released
D) the extent of product produced
E) the overall energy change of a reaction
127.
The rate at which an enzyme-catalyzed reaction occurs can be increased by __________.
A) decreasing substrate concentration
B) releasing the cofactor that was bound to the enzyme
C) increasing enzyme concentration
D) decreasing temperature
E) changing the enzyme's conformation, thereby reducing its affinity for the substrate
128.
Energy from the metabolism of glucose and other fuel substrates is temporarily stored by the
body as __________.
A) ADP
B) ATP
C) AMP
D) inorganic phosphate
E) water
129.
The reaction whereby energy is release from an ATP molecule is called an __________.
A) ATP reduction
B) ATP oxidation
C) ATP hydrolysis
D) ATP synthase
E) ATP hydrogenation
130.
The process of glycolysis breaks glucose into __________ molecule(s) in the presence of
oxygen.
A) 1 pyruvate B) 1 lactate
C) 2 pyruvate
D) 2 lactate
E) 2 glycerol
131.The enzymes of glycolysis are located within the __________ of the cell.
A) inner mitochondrial membrane
B) outer mitochondrial membrane
C) lysosome
D) cytoplasm
E) nucleus
132.
In the presence of a limited oxygen supply, pyruvate is converted to __________.
A) lactate
B) acetyl CoA
C) NADH
D) ATP
E) glucose
133.
The final acceptor of electrons in the electron transport chain is __________.
A) pyruvate
B) carbon dioxide
C) water
D) oxygen
E) glucose
134.
Oxidative phosphorylation refers to __________.
A) enzymes that transfer a phosphate from one molecule to another
B) the requirement for protein kinases to phosphorylate enzymes
C) the requirement that enzymes must be phosphorylated to be active
D) the transport of hydrogen atoms (electrons) through a series of reactions in the mitochondria
E) a reaction that requires ATP
135.
Glucose is stored in muscle and liver cells in the form of __________.
A) starch
B) glycogen
C) cellulose
D) lipids
E) amino acids
136.
Glycogen in muscle is used to __________.
A) contribute to the maintenance of blood glucose
B) convert glucose to amino acids
C) convert glucose to fats
D) fuel the activity of the muscle exclusively
E) both fuel muscle activity and maintain blood glucose
137.
Fatty acids are cleaved from the glycerol of triglyceride molecules via __________.
A) glycolysis
B) the Kreb's cycle
C) glycogenolysis
D) lipolysis
E) the electron transport chain
138.
Proteins that carry molecules across the membrane via active transport are specifically called
__________.
A) channels
B) carriers
C) pumps
D) transporters
E) receptors
139.
Membranes function in a dual role, acting as a __________ that keeps molecules out while at
the same time __________ the exchange of certain molecules.
A) barrier preventing
B) barrier permitting
C) regulator preventing
D) permissive regulator permitting
E) regulator restricting
140.
When molecules are passively transported across a membrane, the direction of their
movement is dictated by the molecule's tendency to move __________.
A) from higher to lower energy
B) from lower to higher energy
C) out of a cell
D) into a cell
E) in both directions; there is no preference
141.
The direction of glucose movement across a membrane (when its transporter is active)
depends upon its __________, which is determined by the __________ of glucose on each
side of the membrane.
A) concentration size
B) concentration energy
C) energy lipid solubility
D) energy concentration
E) lipid solubility energy
142.
Any difference in energy across a membrane is considered the __________ that pushes a
molecule in one direction or the other.
A) magnetic force
B) antagonistic force
C) carrier
D) channel
E) driving force
143.
Molecules tend to move spontaneously __________ their chemical gradient.
A) down
B) up
C) through
D) around
E) over
When more than one ion species (i.e., Na+ and K+) is present on both sides of the
membrane, the chemical driving force acting on Na+ will include __________.
A) both ions
B) potassium only
C) the most concentrated ion
D) sodium only
E) all ions present
144.
145.
__________ is a reflection of the unequal distribution of positive and negative ions across the
plasma membrane.
A) Chemical gradient
B) Extracellular potential
C) Membrane potential
D) Chemical driving force
E) Electrochemical driving force
146.
Comparing intracellular to extracellular fluid, the intracellular fluid has a __________ charge
relative to the outside of a cell due to the presence of more __________ in that solution.
A) positive cations
B) negative anions
C) negative cations
D) positive anions
E) neutral cations
147.
The unequal distribution of charge in solutions on either side of a membrane will lead to a
__________ of charge across the membrane and a __________ of counter ions in a region
close to the membrane.
A) separation clustering
B) collection restriction
C) buildup restriction
D) separation restriction
E) collection clustering
148.
Based solely upon its electrical charge, the inside of a typical cell will tend to attract
extracellular __________ to move inward.
A) proteins
B) anions
C) cations
D) uncharged ions
E) ions whose concentration gradient allows them
149.
Which of the following factors does NOT directly affect the direction or magnitude of the
electrical driving force?
A) the sign of the membrane potential
B) an ion's charge
C) the amplitude of membrane potential
D) the molecular weight of an ion
E) the quantity of charge carried by an ion
150.
The __________ determines the direction and extent of ion movement across a membrane.
A) electrical driving force
B) chemical driving force
C) electrochemical driving force
D) electrical driving force, to the greatest extent, with a small contribution from the chemical driving
force
E) chemical driving force, to the greatest extent, with a small contribution from the electrical driving
force
151.
If the chemical and electrical driving forces are moving an ion in the same direction, the
electrochemical gradient would move that ion __________.
A) in the opposite direction of the chemical and eletrical driving forces.
B) in both directions
C) in the same direction as the chemical and electrical driving force
D) in a direction that cannot be determined from the information presented
E) in a direction that is not predictable
152.
Equilibrium potential describes the membrane potential where the __________ gradient
balances the __________ gradient.
A) chemical temperature
B) chemical electrical
C) electrical permeability
D) temperature density
E) density magnetic
153.
Passive transport of an ion requires that it move __________ its electrochemical gradient.
A) up
B) across
C) down
D) between
E) within
154.
Active transport of an ion usually means that it moves __________ its electrochemical gradient.
A) up
B) across
C) down
D) between
E) within
155.
When talking about ion flux, it is important to remember that ions are always moving in
__________ across a membrane.
A) the outward direction
B) the direction dictated by the electrical gradient
C) one direction only
D) both directions
E) the direction dictated by the chemical gradient
156.
When the term net flux is used to describe ion movement across a membrane, it refers to
__________.
A) the sum of a particular ion moving in both directions
B) a particular ion moving in one direction
C) only the ion moving down its electrochemical gradient
D) the particular ion moving down its chemical gradient
E) the particular ion moving down its electrical gradient
157.
Which of the following does NOT directly determine the rate at which an ion will move
passively across a membrane?
A) magnitude of driving force
B) permeability of the membrane
C) membrane surface area
D) amount of ATP available
E) concentration gradient
158.
How will increases in the concentration difference of an ion across a membrane affect the
rate of diffusion between two compartments?
A) Diffusion rate will not be affected.
B) Diffusion rate will increase.
C) Diffusion rate will progressively decrease until zero.
D) Diffusion rate will decrease.
E) Diffusion rate will remain constant.
Extracellular Na+ is higher than intracellular Na+. If membrane potential were to reach the
equilibrium potential for Na+, in which direction would the net Na+ movement be?
A) inward
B) outward
C) no net movement of Na+ (equal in both directions)
D) varies by cell
E) Na+ would not move across the membrane.
159.
160.
When a substance crossing the membrane is driven by diffusion, the net flux of that molecule
can be described mathematically by __________.
A) the Nernst equation
B) Fick's Law
C) the Navier Stokes equation
D) the Goldman Hodgkins Katz equation
E) Einstein's equation
161.
Which of the following will NOT increase the net flux of an ion across a membrane?
A) elevated permeability of the membrane
B) increased concentration gradient across the membrane
C) enhanced surface area
D) more channels for that ion in the membrane
E) reduced surface area
162.
Which of the following is NOT a factor that affects membrane permeability?
A) lipid solubility of the diffusing substance
B) size and shape of diffusing molecules
C) temperature
D) membrane thickness
E) lipid solubility of the membrane
163.
Molecules with a relatively high lipid solubility are capable of crossing the membrane
__________.
A) directly across the lipid bilayer
B) only through specific protein channels
C) only with the addition of energy
D) indirectly by moving across a carrier protein
E) through specific lipid channels
164.
A membrane's permeability to a molecule is __________ proportional to the size of that
molecule.
A) directly
B) inversely
C) indirectly
D) at times
E) not
94) The permeability of a layer of epithelial cells is __________ proportional to thickness of that cell
layer.
A) directly
B) inversely
C) indirectly
D) at times
E) not
165.
A carrier is a transmembrane protein that moves molecules across the membrane through
__________.
A) small gaps in the fluid portion of the membrane
B) a lipid filled pore
C) a water filled pore
D) opening its gate and allowing molecules through
E) conformational changes in the carrier proteins
166.
In general, the molecules that move through specific channels and carrier proteins are
determined by __________.
A) a water filled pore
B) the molecule's lipid solubility
C) the size of a molecule
D) the unique binding sites on the channel or carrier protein
E) conformational changes in the pore
167.
As the concentration of ions to be moved across the membrane increases, thereby increasing
the net flux of those ions, that carrier will eventually approach a point where it will become
__________ and flux will no longer increase.
A) saturated
B) fatigued
C) marked for degradation
D) restrictive to ion movement
E) energy dependent
168.
What is the main difference between primary and secondary active transport?
A) the location of the binding sites
B) the direction that molecules are being moved across the membrane
C) One uses energy whereas the other requires no energy.
D) the form of energy (ATP vs electrochemical gradient) used to move molecules across the
membrane
E) The molecules that are transported access the binding sites differently.
169.
__________ couples the movement of an ion against its electrochemical gradient to another
ion that is moving down its electrochemical gradient that was established using cellular
energy (ATP).
A) Primary active transport
B) Secondary active transport
C) Tertiary passive transport
D) Primary passive transport
E) Secondary passive transport
170.
Proteins involved in primary active transport are called __________, which act in a way
similar to __________.
A) pumps facilitated diffusion
B) channels pumps
C) pumps channels
D) carriers pumps
E) pumps carriers
For the Na+/K+ pump, hydrolysis of an ATP molecule will result in the movement of
__________.
A) Na+ and K+ out of the cell
B) Na+ and K+ into the cell
C) K+ out and Na+ into the cell
D) Na+ out and K+ into the cell
E) Na+ out of the cell only
171.
Sodium-linked glucose transport, where both Na+ and glucose are moving in the same
direction, is an example of __________.
A) countertransport
B) symport
C) antiport
D) exchange
E) primary active transport
172.
173.
The sodium-proton exchanger is an example of a(n) __________.
A) antiporter
B) cotransporter
C) symporter
D) primary active transporter
E) passive transporter
174.
A(n) __________ functions to passively move ions across a membrane against the direction
of their active transport.
A) leak
B) pump
C) antiporter
D) symporter
E) exchanger
175.
The flow of water across a membrane down its concentration gradient is called __________.
A) leaking
B) symporting
C) facilitated diffusion
D) osmosis
E) antiporting
176.
The total solute concentration of a solution is referred to as its __________.
A) molality
B) percent solution
C) molarity
D) osmolarity
E) water concentration
177.
The osmotic pressure of a solution is a(n) __________.
A) indication of its glucose concentration
B) direct measure of its solvent concentration
C) indirect measure of its solvent concentration
D) direct measure of its solute concentration
E) indirect measure of its solute concentration
178.
Direct communication between cells in contact with one another is accomplished through
__________.
A) ligands
B) receptors
C) gap junctions
D) paracrine chemical messengers
E) endocrine hormones
179.
What type of chemical messenger is released into the bloodstream by an endocrine gland
where it can affect target cells throughout the body?
A) paracrine
B) autocrine
C) hormones
D) cytokines
E) neurotransmitters
180.
Which type of chemical messenger is released from the axon terminal of a nerve cell and
directly stimulates other cells?
A) paracrine chemical messengers
B) autocrine chemical messengers
C) hormones
D) cytokines
E) neurotransmitters
In its role as a __________, calcium is observed to bind to __________ that, when complexed,
provides for the activation of a protein kinase.
A) second messenger a phosphatase
B) first messenger a hydrolase
C) second messenger calmodulin
D) first messenger a protein kinase
E) third messenger calmodulin
181.
The activity of second messengers has the effect of activating a __________, which will
amplify by manyfold the magnitude of the cell's response.
A) cascade of enzymes
B) single enzyme
C) mitochondria
D) receptor
E) lysosome
182.
The function of a second messenger is to __________.
A) buffer a cells response to a ligand
B) isolate the response to the inside of a cell
C) keep calcium involved in these responses
D) amplify the response of the first messenger
E) facilitate the process of covalent modification of a protein
183.
In order to terminate a cAMP-mediated response, the enzyme __________ can be activated
to dephosphorylate cAMP.
A) cAMP decarboxylase
B) cAMP hydrolase
C) cAMP hydrogenase
D) cAMP phosphodiesterase
E) cAMP protein kinase
184.
The __________ and __________ are glands that function to regulate virtually every system
in the body.
A) pancreas hypothalamus
B) pituitary thyroid
C) pituitary hypothalamus
D) adrenal thyroid
E) pancreas adrenal
185.
Which of the following hormones is NOT released from the adrenal gland?
A) acetylcholine
B) aldosterone
C) cortisol
D) androgens
E) epinephrine
Action potentials are related to nerve impulses in that
a. many nerve impulses are required to cause one action potential.
b. propagation of action potentials along a fiber constitutes a nerve impulse
c. active transport of Na+ and K- are required for a nerve impulse but not for an action
potential
d. nerve impulses are stronger responses by the nerve than are action potentials.
186.
If the body had a low calcium level, then this could affect the release of
neurotransmitters by
a. increasing the quantity released from synaptic knobs.
b. breaking down acetylcholine to acetyl and choline in synaptic knobs.
c. causing a greater amount to be synthesized and stored in synaptic knobs
d. causing a decrease in the amount released from synaptic knobs.
187.
The process of transmitting a nerve impulse from one neuron to another involves a
a. nerve impulse stimulating presynaptic dendrites to release a neurotransmitter into a
synaptic cleft.
b. nerve impulse stimulating presynaptic axons to release a neurotransmitter into a synaptic
cleft.
c. neurotransmitter traveling from presynaptic dendrites across a synapse to postsynaptic
axons or a cell body.
d. neurotransmitter traveling from postsynaptic axons across a synapse to presynaptic
dendrites or a cell body.
188.
For cells that communicate by electrical synapses, the message travels between cells via
__________.
A) ions moving across the synaptic cleft
B) the diffusion of neurotransmitters
C) gap junction proteins
D) active transport across the synaptic cleft
E) passive transport across the synaptic cleft
189.
The chemical synapse is bounded by the __________ neuron, from which
neurotransmitters are released across the synaptic cleft, to the __________ neuron,
where the receptors for that neurotransmitter are located.
A) presynaptic : postsynaptic
B) postsynaptic : presynaptic
C) parasynaptic : postsynaptic
D) presynaptic : parasynaptic
E) terminal : presynaptic
190.
The neurotransmitter that is released from the presynaptic neuron must diffuse across
the __________.
A) axon hillock
B) dendrite
C) cell body
D) axon
E) synaptic cleft
191.
The influx of calcium into the axon terminal of a chemical synapse is responsible for the
__________.
A) initiation of an action potential
B) termination of an action potential
C) fusion of vesicles to the membrane and their exocytosis
D) diffusion of the neurotransmitter across the membrane and into the cleft
E) movement of calcium through gap junctions
192.
Which of the following is NOT a mechanism whereby neurotransmitters are rapidly
removed from the synaptic cleft?
A) diffusion out of the cleft
B) degradation by enzymes
C) active reuptake across the presynaptic membrane
D) binding to the receptor
E) transport back up the axon to be immediately repackaged
193.
Neurotransmitters can be reused through the process of __________, where
neurotransmitters are transported across the presynaptic membrane.
A) reuptake
B) regeneration
C) recycling
D) resynthesis
E) receptor binding
194.
A change in the postsynaptic potential that brings membrane potential closer to threshold
is called a(n) __________.
A) excitatory postsynaptic potential
B) inhibitory postsynaptic potential
C) suprathreshold postsynaptic potential
D) hyperpolarizing postsynaptic potential
E) inhibitory presynaptic potential
195.
The opening of sodium channels on the postsynaptic membrane is a clear indication that
a(n) __________ postsynaptic potential has been generated.
A) inhibitory
B) excitatory
C) suprathreshold
D) hyperpolarizing
E) subthreshold
196.
The rapid change in membrane potential that occurs when a __________ channel opens
results from its large electrochemical gradient.
A) sodium
B) potassium
C) calcium
D) chloride
E) magnesium
197.
The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the
__________ of __________ channels.
A) closure : sodium
B) opening : chloride
C) closure : potassium
D) opening : sodium
E) closure : chloride
198.
The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the
__________ of __________ channels.
A) closure : sodium
B) opening : potassium
C) closure : potassium
D) opening : sodium
E) closure : chloride
199.
The opening of a chloride channel acts to __________ the development of an action
potential at the axon hillock.
A) stimulate
B) inhibit
C) facilitate
D) further
E) enhance
200.
Which of the following is a biogenic amine that is NOT classified as a catecholamine?
A) norepinephrine
B) epineprine
C) adrenaline
D) seratonin
E) dopamine
202.
__________ is the primary neurotransmitter released from somatic nerves.
A) Epinephrine
B) Norepinephrine
C) Acetylcholine
D) Dopamine
E) GABA
203.
The location on skeletal muscle that contains a high density of nicotinic receptors.
A) terminal bouton
B) motor end plate
C) motor unit
D) dendrites
E) axon hillock
204.
__________ is located around the border of the motor end plate of a neuromuscular
junction.
A) b2 receptors
B) b3 receptors
C) Acetylcholinesterase
D) Muscarinic receptors
E) Nicotinic receptors
205.
__________ describes the graded change in membrane potential that occurs at the
motor end plate of skeletal muscle.
A) Inhibitory postsynaptic potential
B) End-plate potential
C) Muscarinic potential
D) Adrenergic potential
E) Action potential
The opening of a cation channel that allows both Na + and K+ to move through will cause
the membrane to __________ because of the __________.
A) hyperpolarize : greater K+ electrochemical gradient as compared with Na+
B) hyperpolarize : greater Na+ electrochemical gradient as compared with K+
C) depolarize : greater K+ electrochemical gradient as compared with Ca2+
D) depolarize : greater Na+ electrochemical gradient as compared with K+
E) depolarize : greater Ca2+ electrochemical gradient as compared with Na+
206.
207.
A skeletal muscle is composed of a number of __________, each composed of many
muscle fibers bundled by connective tissue.
A) fascicles
B) myofibrils
C) muscle cells
D) myofilaments
E) sarcomeres
208.
A(n) __________ is a structure composed of connective tissue that transmits force from
contracting skeletal muscle to bone.
A) myofibril
B) fascicle
C) tendon
D) ligament
E) aponeurosis
209.
The __________ is a saclike membranous structure that surrounds each myofibril.
A) sarcolemma
B) sarcoplasmic reticulum
C) transverse tubule
D) nucleus
E) mitochondrion
210.
A __________, the fundamental repeating unit of the myofibril that gives skeletal muscle
its striated appearance, is bordered by __________.
A) crossbridge : Z lines
B) sarcomere : M lines
C) sarcomere : I bands
D) sarcomere : Z lines
E) crossbridge : A bands
211.
Region of the striated muscle's banding patterns that contains ONLY the connections
between the tails of myosin molecules.
A) A band
B) I band
C) H zone
D) Z line
E) M line
212.
The contractile portion of the thin filament is composed of __________ protein.
A) myosin
B) tropomyosin
C) troponin
D) actin
E) titin
213.
The protein component of the thin filament that binds to calcium thereby initiating skeletal
muscle contraction.
A) myosin
B) tropomyosin
C) troponin
D) actin
E) titin
214.
__________ is a structural protein that extends along each thick filament from M line to Z
line.
A) Titin
B) Actin
C) Myosin
D) Tropomyosin
E) Troponin
215.
The shortening of a skeletal muscle fiber during contraction involves __________.
A) the thick filaments shortening
B) the thin filaments shortening
C) the sarcomeres shortening
D) the A bands shortening
E) the Z lines not changing their position
216.
During skeletal muscle contraction, as the muscle shortens, the thick and thin filaments
__________.
A) shorten
B) slide past one another
C) do not interact
D) condense
E) stretch one another
217.
When a skeletal muscle is passively stretched, that cell has a tendency to spring back
once the force that was stretching the muscle is removed due to __________.
A) the passive interaction between actin and myosin (no energy required)
B) the active interaction between actin and myosin (energy required)
C) titin acting as a spring using the energy stored by the stretching
D) actin and myosin acting as a spring using the energy stored by the stretching
E) the elastic connective tissue that surrounds the muscle cells and fascicles
218.
The repeated, oscillating interaction between actin and myosin that results in the
generation of force by a skeletal muscle cell is called __________.
A) crossbridge cycling
B) the sliding-filament model
C) Z line interaction
D) sarcomeric facilitation
E) titin cycling
219.
The myosin head is converted into the high-energy state by __________.
A) binding to ATP only
B) binding to actin
C) the condensation of ATP
D) the hydrolysis of ATP
E) binding to titin
220.
The release of an inorganic phosphate from the myosin molecule directly results in the
__________.
A) development of rigor
B) power stroke
C) cocking of the myosin head
D) binding of actin to myosin
E) breaking of the actin myosin complex
221.
In order for crossbridge cycling to occur, the actin-myosin complex must be broken by the
__________.
A) binding of tropomyosin to myosin
B) binding of ATP to actin
C) binding of the troponin complex to actin
D) conformational change that occurs as the myosin head changes from the high to low energy
state
E) binding of ATP to myosin
222.
The sequence of events that links the action potential to changes in skeletal muscle force
development is called __________.
A) the sliding-filament model
B) crossbridge cycling
C) myoacto coupling
D) excitation-contraction coupling
E) oxidative phosphorylation
223.
Contraction of skeletal muscle fibers is stimulated by __________.
A) autonomic nerves
B) sympathetic nerve
C) motor nerves
D) parasympathetic nerves
E) afferent nerves
224.
Which ion's intracellular concentration is low when the skeletal muscle is relaxed and
increases dramatically during muscle cell contraction?
A) sodium
B) potassium
C) magnesium
D) calcium
E) selenium
225.
The binding of calcium to the subunit of troponin will directly result in __________.
A) the binding of ATP to myosin
B) the further release of calcium into the cytoplasm
C) the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule
D) the movement of tropomyosin, thereby exposing the actin-binding site on the myosin molecule
E) the hydrolysis of ATP
226.
In order to allow discrete contractile events to occur, calcium is rapidly removed from the
cytoplasm via __________.
A) calcium pumps (active transport of calcium)
B) dihydropyridine channels
C) ryanodine channels
D) calcium-sequestering proteins in the cytoplasm
E) calcium-binding proteins on the sarcoplasmic reticulum
227.
Which of the following is NOT part of the process whereby skeletal muscles relax?
A) Sarcolemmal calcium channels open to allow the efflux of calcium.
B) The binding of calcium to a low-affinity site closes sarcoplasmic reticular calcium channels.
C) A calcium pump actively removes calcium.
D) Calcium bound to troponin decreases (reversible).
E) A myosin-binding site on the actin molecule is blocked by tropomyosin.
228.
An increase in the rate of utilization of ATP in a muscle cell will __________.
A) decrease muscle activity
B) stimulate the enzymes that control ATP-producing reactions
C) inhibit the enzymes that control ATP-producting reactions
D) increase the storage of energy
E) increase muscle activity
229.
The reaction that creates creatine phosphate is driven by the enzyme __________.
A) creatine phosphatase
B) creatine hydrolase
C) creatine hydrogenase
D) creatine kinase
E) ATP hydrolase
230.
As the intensity of exercise increases, the muscles switch from oxidative to substratelevel phosphorylation, resulting in the increased generation of __________.
A) lactic acid
B) water from the electron transport chain
C) glucose
D) fatty acid
E) ATP
231.
When an action potential is generated within a motor nerve, __________.
A) the muscle cells of the motor unit will occasionally contract
B) only select muscle cells within the motor unit are stimulated to contract
C) every muscle cell of the motor unit is stimulated to contract
D) the muscle cells from a neighboring motor unit will contract
E) all of the muscle cells within the motor unit are stimulated to relax
232.
For a single twitch, a muscle cell will spend a majority of its time in the __________
phase.
A) latent
B) contraction
C) plateau
D) relaxation
E) initial
233.
Which of the following is NOT part of the explanation for the all-or-nothing property of an
isometric twitch contraction of skeletal muscle?
A) equivalent calcium reuptake by the sarcoplasmic reticulum
B) equivalent calcium released by each action potential
C) equivalent activation of calmodulin stimulating myosin light-chain kinase activity
D) equal numbers of crossbridges activated by the calcium released
E) all-or-nothing property of the action potential generated by a skeletal muscle
234.
Which of the following is a property of isotonic skeletal muscle contraction?
A) slow increase in force with no change in muscle length
B) rapid increase in force with no change in muscle length
C) muscle length will not be changed by contraction
D) load > force generated by muscle
E) load < force generated by muscle
235.
__________ is the property of skeletal muscle whereby repeated action potentials
enhance the force developed by the muscle cell.
A) Length-tension relationship
B) Summation
C) Force-velocity relationship
D) External tension
E) Internal tension
236.
When the frequency of an action potential is high enough that further increases have no
effect on force development, the skeletal muscle cell is said to be at __________.
A) external tetanus
B) unfused tetanus
C) incomplete tetanus
D) maximum tetanic tension
E) fused tetanus
237.
When the muscle contracts isometrically, its sarcomeres begin to shorten before the muscle
cell starts to shorten due to the __________.
A) stretching of the series elastic elements
B) stretching of the contractile components
C) relaxation of the series elastic elements
D) relaxation of the contractile components
E) contraction of the series elastic elements
238.
Which of the following is NOT one of the effects of increasing load on the velocity of
shortening of a muscle?
A) The latent period increases.
B) The duration of shortening decreases.
C) The velocity of shortening decreases.
D) The slope of the distance vs. time curve decreases.
E) Maximal velocity occurs with minimal load.
239.
As skeletal muscle is further stretched beyond the length where optimum force is developed,
__________.
A) the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases
B) the thin filaments are pulled away from one another, thereby reducing their ability to interact with
myosin
C) the thick filaments are pulled away from one another, thereby reducing their ability to interact with
actin
D) the thick filaments overlap one another, thereby reducing their ability to interact with actin
E) the thin filaments overlap one another, thereby reducing their ability to interact with myosin
240.
Which of the following does NOT influence the force generated by an individual muscle fiber?
A) frequency of stimulation
B) fiber diameter
C) length-tension curve
D) recruitment
E) summation
241.
__________ describes an increase in the number of active motor units that would increase
the force developed by a skeletal muscle.
A) Recruitment
B) Summation
C) Treppe
D) Tetanus
E) Length-tension relationship
242.
The size principle of motor unit recruitment states that __________.
A) motor units with the larger diameter motor nerves are recruited first
B) motor nerves from larger motor units reach threshold easier
C) larger motor units are recruited first
D) smaller motor units are recruited first
E) motor units with fewer but larger fibers are recruited first
243.
The mechanism responsible for the size principle involves __________.
A) larger motor nerve fibers that contain the greatest number of muscle cells and reach threshold
easier than smaller nerves
B) larger sympathetic nerve fibers that contain the greatest number of muscle cells and reach
threshold easier than smaller nerves
C) smaller sympathetic nerve fibers that contain the least number of muscle cells and reach threshold
easier than larger nerves
D) smaller motor nerve fibers that contain the least number of muscle cells and reach threshold
easier than larger nerves
E) smaller motor nerve fibers that contain the greatest number of muscle cells and reach threshold
easier than larger nerves
244.
Shortening velocity of skeletal muscle is zero when __________.
A) load < external force
B) there is an isotonic muscle action
C) there is no load on the muscle (zero load)
D) load is maximal (the muscle cannot produce enough force to move the load)
E) the first load, which is relatively small, is applied to the muscle
245.
Normalized for any variability in skeletal muscle length, the speed of contraction of a skeletal
muscle fiber is dependent upon __________.
A) the number of sarcomeres in series
B) the rate of myosin ATPase activity
C) the number of sarcomeres in parallel
D) the rate of actin ATPase activity
E) the rate of myosin light-chain ATPase activity
246.
Which of the following is NOT a property of glycolytic fibers as compared to oxidative fibers?
A) high capacity for lactic acid production
B) fewer capillaries
C) absence of myoglobin
D) poor ability to produce ATP in the absence of oxygen
E) readily fatiguable
247.
Which of the following is NOT a property of oxidative fibers as compared to glycolytic fibers?
A) poor production of ATP under anaerobic conditions
B) high capacity for lactic acid production
C) presence of myoglobin
D) many capillaries
E) fatigue resistance
248.
Which of the following is NOT an adaptation of skeletal muscle that would be observed in
response to aerobic training.
A) an increase in mitochondrial density
B) an increase in capillary density
C) an increase in the number of oxidative fibers (especially fast)
D) an increase in the diameter of the skeletal muscle fibers
E) an increase in the concentration of oxidative enzymes
249.
Which of the following is NOT an adaptation of skeletal muscle that would be observed in
response to high-intensity training.
A) a decrease in mitochondrial density
B) a decrease in capillary density
C) a decrease in the number of oxidative fibers (especially fast)
D) an increase in the diameter of the skeletal muscle fibers
E) an increase in the concentration of glycolytic enzymes
250.
Which of the following is NOT a characteristic of smooth muscle?
A) Contractile filaments attach to the membrane at the dense body.
B) the presence of sarcomeres
C) Troponin and tropomyosin do not regulate actin-myosin interactions.
D) the absence of a striated pattern
E) actin-myosin interaction driven by myosin light-chain kinase
251.
What is the source of variability in a smooth muscle cell's response from different organs to
autonomic nervous activity (some relax to sympathetic nervous output while others
constrict)?
A) the amount of neurotransmitter released into the synaptic cleft
B) the duration of neurotransmitter release from the autonomic nerves
C) the neurotransmitter released by the autonomic nervous system
D) the type of receptor present on the organ
E) the presynaptic modulation of the autonomic nerves
252.
The synchronization of smooth muscle cell activity is mediated by __________.
A) gap junctions exclusively
B) neuromuscular junctions exclusively
C) the release of neurotransmitter from numerous varicosities exclusively
D) neuromuscular junctions and gap junctions
E) gap junctions and the release of neurotransmitter from numerous autonomic varicosities
253.
Which of the following is NOT different between smooth and skeletal muscles?
A) Skeletal muscle requires excitatory inputs whereas smooth muscle receives both excitatory and
inhibitory inputs.
B) Activation of skeletal muscle requires an action potential to be generated whereas smooth muscle
does not always require an action potential.
C) Neural input targets specific skeletal muscle whereas smooth muscle is affected in large numbers.
D) Skeletal muscle is connected by gap junctions whereas smooth muscle cells are not coupled.
E) Skeletal muscle is regulated by the somatic nervous system whereas smooth muscle is regulated
by the autonomic nervous system.