Question 1

Which statement about muscle contractile proteins is true?

Accepted Answer

A)  Three chains of actin monomers twisted together form an actin filament. 
B)  A molecule of myosin consists of two long linear polypeptide chains each with a globular head. 
C)  A myosin filament consists of a single myosin molecule with its heads projecting at the ends of the filament. 
D)  The polypeptides that make up actin have globular heads. 
E)  Tropomyosin twists around the myosin molecule. 
A)  Three chains of actin monomers twisted together form an actin filament. 
B)  A molecule of myosin consists of two long linear polypeptide chains each with a globular head. 
C)  A myosin filament consists of a single myosin molecule with its heads projecting at the ends of the filament. 
D)  The polypeptides that make up actin have globular heads. 
E)  Tropomyosin twists around the myosin molecule.

Question 2

Which feature characterizes titin?

Accepted Answer

A)  Holds bundles of myosin filaments in a centered position within the sarcomere 
B)  Smallest protein in the body 
C)  Responsible for resistance to stretch in contracted skeletal muscles 
D)  Stretchable between ends of actin bundles and Z lines 
E)  Is absent from the H zone of a sarcomere 
A)  Holds bundles of myosin filaments in a centered position within the sarcomere 
B)  Smallest protein in the body 
C)  Responsible for resistance to stretch in contracted skeletal muscles 
D)  Stretchable between ends of actin bundles and Z lines 
E)  Is absent from the H zone of a sarcomere

Question 3

Other than preformed ATP, a storage compound in muscles called _______ is part of the immediate system for obtaining ATP.

Accepted Answer

The answer of Other than preformed ATP, a storage compound...

Question 4

Smooth muscle differs from both cardiac and skeletal muscle in that

Accepted Answer

A)  it can act as a pacemaker for rhythmic contractions. 
B)  its contractions are not due to interactions between neighboring microfilaments. 
C)  its neighboring cells are electrically connected by gap junctions. 
D)  its neighboring cells are tightly coupled by intercalated discs. 
E)  its cell membranes are depolarized by stretching. 
A)  it can act as a pacemaker for rhythmic contractions. 
B)  its contractions are not due to interactions between neighboring microfilaments. 
C)  its neighboring cells are electrically connected by gap junctions. 
D)  its neighboring cells are tightly coupled by intercalated discs. 
E)  its cell membranes are depolarized by stretching.

Question 5

How does tropomyosin control muscle contraction?

Accepted Answer

A)  It provides a bridge between actin and myosin. 
B)  It provides a site where ATP can be utilized. 
C)  Changes in its conformation expose actin-myosin binding sites. 
D)  It transmits an electric charge to the filaments. 
E)  Changes in its shape open membrane channels. 
A)  It provides a bridge between actin and myosin. 
B)  It provides a site where ATP can be utilized. 
C)  Changes in its conformation expose actin-myosin binding sites. 
D)  It transmits an electric charge to the filaments. 
E)  Changes in its shape open membrane channels.

Question 6

Refer to the figure showing sarcomeres of various lengths.   Which sarcomere(s) is/are poised to generate the greatest amount of force? Which sarcomere(s) is/are poised to generate the least amount of force? Explain your answer.

Accepted Answer

Sarcomere B will be able to generate the

Question 7

Which statement about skeletal muscle contraction is true?

Accepted Answer

A)  A single action potential at the neuromuscular junction is not sufficient to cause a muscle to twitch. 
B)  An action potential in the muscle cell activates contraction by releasing Na+ into the sarcoplasm. 
C)  Twitches are able to sum when Ca2+ is quickly removed from the sarcoplasm between action potentials. 
D)  Summation of twitches leads to a graded increase in the tension that can be generated by a single muscle fiber. 
E)  The tension generated by a muscle is invariable. 
A)  A single action potential at the neuromuscular junction is not sufficient to cause a muscle to twitch. 
B)  An action potential in the muscle cell activates contraction by releasing Na+ into the sarcoplasm. 
C)  Twitches are able to sum when Ca2+ is quickly removed from the sarcoplasm between action potentials. 
D)  Summation of twitches leads to a graded increase in the tension that can be generated by a single muscle fiber. 
E)  The tension generated by a muscle is invariable.

Question 8

ATP is supplied to your muscles through several systems.As you exercise, where does the ATP you use come from, in order from most accessible to most slowly produced?

Accepted Answer

A)  Stored ATP and creatine phosphate; glycolysis in the cytoplasm; oxidative metabolism in mitochondria 
B)  Preformed creatine phosphate; glycolysis in the mitochondria; oxidative metabolism in the cytoplasm 
C)  Oxidative metabolism in the cytoplasm; glycolysis in mitochondria; ATP from creatine phosphate 
D)  Glycolysis in the cytoplasm; oxidative metabolism in mitochondria; stored ATP and creatine phosphate 
E)  Glycolysis; ATP from creatine phosphate; oxidative metabolism 
A)  Stored ATP and creatine phosphate; glycolysis in the cytoplasm; oxidative metabolism in mitochondria 
B)  Preformed creatine phosphate; glycolysis in the mitochondria; oxidative metabolism in the cytoplasm 
C)  Oxidative metabolism in the cytoplasm; glycolysis in mitochondria; ATP from creatine phosphate 
D)  Glycolysis in the cytoplasm; oxidative metabolism in mitochondria; stored ATP and creatine phosphate 
E)  Glycolysis; ATP from creatine phosphate; oxidative metabolism

Question 9

Which statement about bone cells is true?

Accepted Answer

A)  When osteoclasts become trapped in deposited bone, they are considered osteocytes. 
B)  Osteoblasts exist within lacunae. 
C)  Osteoclasts are derived from the cell lineage that produces osteocytes. 
D)  Osteocytes communicate with other osteocytes via long cellular extensions. 
E)  Bone is a nonliving tissue. 
A)  When osteoclasts become trapped in deposited bone, they are considered osteocytes. 
B)  Osteoblasts exist within lacunae. 
C)  Osteoclasts are derived from the cell lineage that produces osteocytes. 
D)  Osteocytes communicate with other osteocytes via long cellular extensions. 
E)  Bone is a nonliving tissue.

Question 10

Refer to the figure showing the fiber types in the leg muscles of two runners.Arrows represent the duration (length of arrow) and speed of running (thickness of arrow).   Based on the figure we can surmise that the fibers labeled 1 _______ than the fibers labeled 2.

Accepted Answer

A)  have more mitochondria 
B)  are supplied with more capillaries 
C)  contain more lipids 
D)  use up their major energy source more quickly 
E)  contain more myoglobin 
A)  have more mitochondria 
B)  are supplied with more capillaries 
C)  contain more lipids 
D)  use up their major energy source more quickly 
E)  contain more myoglobin

Question 11

Which of the following about tetanus is true?

Accepted Answer

A)  It is the minimum level of contraction of a muscle fiber. 
B)  During tetanus there is a continuous presence of high levels of calcium ions in the sarcoplasm. 
C)  It is sustained by a lack of ATP. 
D)  Experiencing repeated tetanic contractions puts a person at risk for developing the disease tetanus. 
E)  It ends when a source of ATP is added to the muscle. 
A)  It is the minimum level of contraction of a muscle fiber. 
B)  During tetanus there is a continuous presence of high levels of calcium ions in the sarcoplasm. 
C)  It is sustained by a lack of ATP. 
D)  Experiencing repeated tetanic contractions puts a person at risk for developing the disease tetanus. 
E)  It ends when a source of ATP is added to the muscle.

Question 12

Which statement about smooth muscle is true?

Accepted Answer

A)  Smooth muscle of the gut is under voluntary control. 
B)  Smooth muscle cells are multinucleated. 
C)  Smooth muscle appears striated when viewed with the microscope. 
D)  Gap junctions are common in smooth muscle. 
E)  Stretched smooth muscle cells do not contract. 
A)  Smooth muscle of the gut is under voluntary control. 
B)  Smooth muscle cells are multinucleated. 
C)  Smooth muscle appears striated when viewed with the microscope. 
D)  Gap junctions are common in smooth muscle. 
E)  Stretched smooth muscle cells do not contract.

Question 13

Refer to figure of the knee joint and the bones and muscles of the human leg.   The ligament, labeled _______ in this figure, must be able to stretch when the knee flexes.

Accepted Answer

The answer of Refer to figure of the knee joint...

Question 14

Which statement about arthropod skeletons is true?

Accepted Answer

A)  Muscles attach to their rigid external skeleton. 
B)  Cells external to the cuticle secrete it. 
C)  Typically, muscles create movement by pulling on rigid internal structures. 
D)  Joints of the arthropod cuticle contain stiffening materials. 
E)  During molting, cells under the cuticle secrete a substance that dissolves chitin. 
A)  Muscles attach to their rigid external skeleton. 
B)  Cells external to the cuticle secrete it. 
C)  Typically, muscles create movement by pulling on rigid internal structures. 
D)  Joints of the arthropod cuticle contain stiffening materials. 
E)  During molting, cells under the cuticle secrete a substance that dissolves chitin.

Question 15

Some athletes hoping to improve their performance take creatine as a dietary supplement.There are some reports that creatine supplements boost performance in activities that require short bursts of energy, such as sprinting, but not in those that require endurance.Why might this be the case?

Accepted Answer

Taking creatine supplements may increase

Question 16

When troponin binds calcium,

Accepted Answer

A)  it allows tropomyosin to bind actin. 
B)  ion channels open, and sodium rushes into the muscle cells. 
C)  it changes conformation, twisting tropomyosin and exposing the actin-myosin binding site. 
D)  it changes conformation, exposing the ATP binding site and allowing the actin-myosin bond to break. 
E)  it binds to calmodulin and starts a cascade by activating myosin kinase. 
A)  it allows tropomyosin to bind actin. 
B)  ion channels open, and sodium rushes into the muscle cells. 
C)  it changes conformation, twisting tropomyosin and exposing the actin-myosin binding site. 
D)  it changes conformation, exposing the ATP binding site and allowing the actin-myosin bond to break. 
E)  it binds to calmodulin and starts a cascade by activating myosin kinase.

Question 17

Vertebrate skeletal muscles are categorized as excitable cells because

Accepted Answer

A)  they can be stimulated by ATP. 
B)  they can be stimulated by an electric charge. 
C)  they can secrete neurotransmitter. 
D)  their membranes generate and conduct action potentials. 
E)  they can attain a high level of activity. 
A)  they can be stimulated by ATP. 
B)  they can be stimulated by an electric charge. 
C)  they can secrete neurotransmitter. 
D)  their membranes generate and conduct action potentials. 
E)  they can attain a high level of activity.

Question 18

Which feature is an advantage of endoskeletons over exoskeletons?

Accepted Answer

A)  Muscles can attach more firmly to bones than to the cuticle. 
B)  An endoskeleton provides better protection. 
C)  Joints are present in endoskeletons but not in exoskeletons. 
D)  With an endoskeleton, growth is possible without shedding of the skeleton. 
E)  Endoskeletons are stiffer than exoskeletons. 
A)  Muscles can attach more firmly to bones than to the cuticle. 
B)  An endoskeleton provides better protection. 
C)  Joints are present in endoskeletons but not in exoskeletons. 
D)  With an endoskeleton, growth is possible without shedding of the skeleton. 
E)  Endoskeletons are stiffer than exoskeletons.

Question 19

Which statement about growing long bones of the legs and arms in the human skeleton is true?

Accepted Answer

A)  Ossification begins at each end of a long bone and then moves to the center. 
B)  An epiphyseal plate made of cartilage separates each end of the bone from the shaft. 
C)  Long bones are made up entirely of compact bone. 
D)  Elongation occurs at regions of spongy bone called epiphyseal plates. 
E)  Growth stops when ossification centers fill in the central cavity of the bone. 
A)  Ossification begins at each end of a long bone and then moves to the center. 
B)  An epiphyseal plate made of cartilage separates each end of the bone from the shaft. 
C)  Long bones are made up entirely of compact bone. 
D)  Elongation occurs at regions of spongy bone called epiphyseal plates. 
E)  Growth stops when ossification centers fill in the central cavity of the bone.

Question 20

If a spontaneous mutation arose in the gene for a ryanodine receptor within a nucleus of a skeletal muscle cell, that cell would most likely (still be able/be unable) _______ to contract.

Accepted Answer

The answer of If a spontaneous mutation arose in the...

Exam 47: Musculoskeletal Systems

Which statement about muscle contractile proteins is true?

Which feature characterizes titin?

Other than preformed ATP, a storage compound in muscles called _______ is part of the immediate system for obtaining ATP.

Smooth muscle differs from both cardiac and skeletal muscle in that

How does tropomyosin control muscle contraction?

Refer to the figure showing sarcomeres of various lengths. Which sarcomere(s) is/are poised to generate the greatest amount of force? Which sarcomere(s) is/are poised to generate the least amount of force? Explain your answer.

Which statement about skeletal muscle contraction is true?

ATP is supplied to your muscles through several systems.As you exercise, where does the ATP you use come from, in order from most accessible to most slowly produced?

Which statement about bone cells is true?

Refer to the figure showing the fiber types in the leg muscles of two runners.Arrows represent the duration (length of arrow) and speed of running (thickness of arrow). Based on the figure we can surmise that the fibers labeled 1 _______ than the fibers labeled 2.

Which of the following about tetanus is true?

Which statement about smooth muscle is true?

Refer to figure of the knee joint and the bones and muscles of the human leg. The ligament, labeled _______ in this figure, must be able to stretch when the knee flexes.

Which statement about arthropod skeletons is true?

Some athletes hoping to improve their performance take creatine as a dietary supplement.There are some reports that creatine supplements boost performance in activities that require short bursts of energy, such as sprinting, but not in those that require endurance.Why might this be the case?

When troponin binds calcium,

Vertebrate skeletal muscles are categorized as excitable cells because

Which feature is an advantage of endoskeletons over exoskeletons?

Which statement about growing long bones of the legs and arms in the human skeleton is true?

If a spontaneous mutation arose in the gene for a ryanodine receptor within a nucleus of a skeletal muscle cell, that cell would most likely (still be able/be unable) _______ to contract.

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