Question 1

Which protein contains a binding site for ATP?
A)troponin
B)myosin
C)tropomyosin
D)myelin
E)All muscle proteins must have an ATP binding sitE.

Accepted Answer

Myosin is a motor protein that binds to ATP and uses it to power muscle contractions. Troponin and tropomyosin are regulatory proteins that control muscle contraction and do not directly bind ATP. Myelin is a type of lipid that forms an insulating sheath around nerves and is not a muscle protein. The last option is not entirely accurate as not all muscle proteins have an ATP binding site.

Question 2

Vertebrate bone consists primarily of a crystalline mixture of A)Ca²⁺,PO₄^-2. B)Ca²⁺,SO₄^-2. C)Ca²⁺,Cl₂. D)Na⁺,Cl^-. E)Adenosine,PO₄^-2.

Accepted Answer

Vertebrate bone primarily consists of hydroxyapatite, a crystalline structure composed of calcium (Ca), phosphorus (P), and oxygen (O), which matches the composition described in option A.

Question 3

Muscle cells are stimulated by acetylcholine released from the terminals of
A)transverse tubules.
B)motor neuron axons.
C)sensory cell axons.
D)motor neuron dendrites.
E)sensory cell dendrites.

Accepted Answer

Muscle cells are stimulated by acetylcholine released from the terminals of motor neuron axons. Acetylcholine facilitates the contraction of muscles by binding to receptors on the surface of muscle cells, which opens ion channels and causes the muscles to contract. Transverse tubules are invaginations in the muscle cell membrane that help conduct electrical signals throughout the muscle cell. Sensory cells do not directly control muscle contraction. Motor neuron dendrites also do not directly control muscle contraction, as they receive signals from other neurons.

Question 4

What is the role of calcium in muscle contractions?
A)to break the cross-bridges as a cofactor in the hydrolysis of ATP
B)to bind with troponin,changing its shape so that binding sites on the actin filament are exposed
C)to transmit the action potential across the neuromuscular junction
D)to spread the action potential through the T-tubules
E)to re-establish the polarization of the plasma's membrane following an action potential

Accepted Answer

Calcium binds with troponin, changing its shape so that binding sites on the actin filament are exposed. This allows myosin to attach to the actin filament, initiating muscle contractions.

Question 5

During muscular contraction,cross-bridges form between _____ and _____ .
A)actin,myosin
B)actin,tropomyosin
C)myosin,troponin
D)myosin,tropomyosin
E)troponin,calmodulin

Accepted Answer

During muscular contraction, cross-bridges form between the actin and myosin filaments. The myosin heads bind to the actin filaments and cause a sliding movement, resulting in muscle contraction. Troponin and tropomyosin are regulatory proteins that are involved in controlling the interaction between actin and myosin, but they do not directly form cross-bridges. Calmodulin is a calcium-binding protein involved in muscle relaxation, but it is not directly involved in muscle contraction.

Question 6

The type of muscle that typically surrounds hollow tubes and organs like the stomach is
A)smooth muscle.
B)skeletal muscle.
C)cardiac muscle.
D)striated muscle.
E)voluntary musclE.

Accepted Answer

Smooth muscle is involuntary and can be found in the walls of hollow organs such as the stomach, intestines, and uterus. It is responsible for controlling movements in these structures. Skeletal muscle, on the other hand, is attached to bones and is responsible for voluntary movements. Cardiac muscle makes up the walls of the heart and is responsible for involuntary contractions to pump blood. Striated muscle refers to skeletal and cardiac muscle, which have a striped appearance under a microscope. Voluntary muscle refers to skeletal muscle that is under voluntary control.

Question 7

In muscle function at the sarcomere level,the formation of cross-bridges is regulated by the binding of ___ ions to ____.
A)calcium,troponin
B)calcium,tropomyosin
C)calcium,myosin
D)sodium,troponin
E)sodium,tropomyosin

Accepted Answer

The formation of cross-bridges in muscle function at the sarcomere level is regulated by the binding of calcium ions to troponin. This binding causes a conformational change in the troponin-tropomyosin complex, ultimately exposing the binding sites on the actin filaments for myosin heads to attach and form cross-bridges.

Question 8

What are some of the disadvantages to having an exoskeleton?
A)Vulnerability during molting
B)Bulkiness reduces ability to move
C)Vulnerability to dessication
D)Bulkiness makes animal heavy

Accepted Answer

The answer of What are some of the disadvantages to...

Question 9

A new muscle is found in an undiscovered species and your HYPERLINK "#" job is to classify the muscle type.When examined under a microscope there does not appear to be any straitions.When stimulated,muscle contraction time is very slow,around 30 seconds.When observed in a fully anesthetized specimen,the muscle is continuously contrating.What muscle type does this myster muscle most likely belong to?
A)Cardiac muscle
B)Skeletal muscle
C)Smooth muscle

Accepted Answer

The muscle described does not have striations, which eliminates the possibility of it being skeletal or cardiac muscle. The slow contraction time and continuous contraction in an anesthetized specimen indicate that it is most likely smooth muscle.

Question 10

A bone soaked in acid for an extended period will become rubbery;you can bend it in half,twist it,sometimes even tie it into a knot! What aspect(s)of the bone's composition do you think has changed due to the acid? A)The acid removed the inorganic,mineral components of the bone. B)The acid removed the HYPERLINK "#" collagen from the bone. C)The acid added Ca²⁺to the bone. D)Nothing.Over time,bones naturally become rubbery due to decomposition. E)The osteoblasts are stimulated by the acid to secrete more HYPERLINK "#" collagen

Accepted Answer

Collagen is the protein that gives bones their strength and flexibility. Acid can break down collagen, which would make the bone rubbery and flexible. The inorganic mineral components of the bone, such as calcium and phosphate, are not affected by acid and would remain intact. Option A is incorrect because removing the mineral components would make the bone weaker, not rubbery. Option C is incorrect because Ca²⁺ is not a known substance. Option D is incorrect because bones do not naturally become rubbery due to decomposition. Option E is incorrect because acid would not stimulate osteoblasts to secrete more collagen.

Question 11

For the hierarchy of skeletal muscle organization,which accurately lists the order of structures from "small" to "big"?
A)sarcomere,myofibril,muscle fiber,motor unit
B)myofibril,muscle fiber,sarcomere,motor unit
C)motor unit,myofibril,muscle fiber,sarcomere
D)motor unit,sarcomere,muscle fiber,myofibril
E)None of the choices are correct.

Accepted Answer

The correct order from smallest to largest is sarcomere (the basic contractile unit of muscle fiber), myofibril (a bundle of sarcomeres), muscle fiber (a single muscle cell), and motor unit (a motor neuron and the muscle fibers it controls).

Question 12

Arthropod exoskeletons are composed primarily of
A)chitin.
B)calcium carbonate.
C)collagen.
D)cartilage.
E)sclerotin.

Accepted Answer

Arthropod exoskeletons are primarily composed of chitin, a polysaccharide that provides structural support and protection. Calcium carbonate may also be present in some arthropod exoskeletons, but it is not the primary component. Collagen and cartilage are found in the connective tissues of vertebrates and are not significant components of arthropod exoskeletons. Sclerotin is a protein found in the exoskeletons of certain insects, but again, it is not the primary component of arthropod exoskeletons.

Question 13

Determine what type of skeletal anatomy is being described in the following account.This skeletal system is found in both terrestrial and aquatic animals.It provides an anchor for muscle attachment and thus aids in locomotion.It is composed of minerals and helps support and protect the rest of the body.
A)An endoskeleton
B)An exoskeleton
C)Neither an endoskeleton nor an exoskeleton
D)Both an endoskeleton and an exoskeleton

Accepted Answer

The answer of Determine what type of skeletal anatomy is...

Question 14

A fish will rapidly dart away from a sudden disturbance,like a pebble thrown into the water.Ususally the fish only swims a short distance before resuming normal,slower locomotion.What type of skeletal muscle fibers does the fish use when darting away?
A)Slow-oxidative
B)Fast-oxidative
C)Fast-glycolytic

Accepted Answer

Fast-glycolytic muscle fibers are specialized for short bursts of powerful movement, making them well-suited for quick, sudden movements like darting away from a disturbance. Slow-oxidative fibers are better suited for sustained, endurance-type activities, while fast-oxidative fibers are intermediate between slow-oxidative and fast-glycolytic.

Question 15

What is the correct sequence of events in cross-bridge cycling?
A)Myosin cross-bridge binds to actin,the powerstroke moves the thin filament relative to the thick filament,ATP binds to myosin and cross-bridge detachment occurs,ATP is hydrolyzed and the myosin head is "cocked"
B)The powerstroke moves the thin filament relative to the thick filament,myosin cross-bridge binds to actin,ATP binds to myosin and cross-bridge detachment occurs,ATP is hydrolyzed and the myosin head is "cocked"
C)Myosin cross-bridge binds to actin,ATP is hydrolyzed and the myosin head is "cocked," the powerstroke moves the thin filament relative to the thick filament,ATP binds to myosin and cross-bridge detachment occurs
D)Myosin cross-bridge binds to actin,ATP binds to myosin and cross-bridge detachment occurs,the powerstroke moves the thin filament relative to the thick filament,ATP is hydrolyzed and the myosin head is "cocked"
E)These events can occur in any sequence without affecting muscle function.

Accepted Answer

The correct sequence for cross-bridge cycling in muscle contraction starts with the myosin cross-bridge binding to actin. Following this, the power stroke occurs, moving the thin filament relative to the thick filament. ATP then binds to myosin, leading to cross-bridge detachment. Finally, ATP is hydrolyzed, which "cocks" the myosin head, preparing it for another cycle of binding.

Question 16

Release of cross-bridges depends most directly on
A)calcium ions.
B)potassium ions.
C)adenosine diphosphate.
D)adenosine triphosphate.
E)creatine phosphatE.

Accepted Answer

Release of cross-bridges in muscle contraction depends most directly on the presence of adenosine triphosphate (ATP). When ATP binds to the myosin head, it causes the cross-bridge between actin and myosin to release, allowing for muscle relaxation or the next cycle of contraction.

Question 17

What structural component in skeletal and cardiac muscle conducts action potentials from the outer surface of the muscle fiber inside to the myofibrils?
A)actin
B)tropomyosin
C)troponin
D)transverse tubule
E)None of thesE.

Accepted Answer

The transverse tubule (T-tubule) is a structural component present in both skeletal and cardiac muscle fibers that conducts action potentials from the outer surface of the fiber inside to the myofibrils. This process allows for coordinated contraction of muscle fibers. Actin, tropomyosin, and troponin are all structural components directly involved in the contractile process of muscle fibers, but they do not conduct action potentials.

Question 18

Each skeletal muscle cell constitutes a single
A)motor unit.
B)muscle fiber.
C)sarcolemma.
D)myofibril.
E)sarcomerE.

Accepted Answer

Each skeletal muscle cell is referred to as a muscle fiber.

Question 19

The primary reservoir for calcium that is released during excitation-contraction coupling in a skeletal muscle fiber is the
A)sarcoplasmic reticulum.
B)endoplasmic reticulum.
C)transverse tubules.
D)Golgi bodies.
E)troponin.

Accepted Answer

The sarcoplasmic reticulum is the primary reservoir for calcium in skeletal muscle fibers. When an action potential travels along the transverse tubules, it triggers the release of calcium from the sarcoplasmic reticulum, which then binds to troponin and initiates muscle contraction. The other options listed are not involved in calcium release during excitation-contraction coupling.

Question 20

The thick filament is composed almost entirely of _____ molecules.
A)actin
B)myosin
C)troponin
D)tropomyosin
E)thrombin

Accepted Answer

The thick filament is primarily composed of myosin molecules, which are responsible for generating the force required for muscle contraction. Actin, troponin, and tropomyosin are components of the thin filaments, which interact with the thick filaments during muscle contraction. Thrombin is not a component of muscle anatomy, but rather a blood clotting enzyme.

Quiz 34: Muscular-Skeletal Systems

Which protein contains a binding site for ATP?

Vertebrate bone consists primarily of a crystalline mixture of

Muscle cells are stimulated by acetylcholine released from the terminals of

What is the role of calcium in muscle contractions?

During muscular contraction,cross-bridges form between _ and _ .

The type of muscle that typically surrounds hollow tubes and organs like the stomach is

In muscle function at the sarcomere level,the formation of cross-bridges is regulated by the binding of _ ions to __.

What are some of the disadvantages to having an exoskeleton?

A bone soaked in acid for an extended period will become rubbery;you can bend it in half,twist it,sometimes even tie it into a knot! What aspect(s) of the bone's composition do you think has changed due to the acid?

For the hierarchy of skeletal muscle organization,which accurately lists the order of structures from "small" to "big"?

Arthropod exoskeletons are composed primarily of

A fish will rapidly dart away from a sudden disturbance,like a pebble thrown into the water.Ususally the fish only swims a short distance before resuming normal,slower locomotion.What type of skeletal muscle fibers does the fish use when darting away?

What is the correct sequence of events in cross-bridge cycling?

Release of cross-bridges depends most directly on

What structural component in skeletal and cardiac muscle conducts action potentials from the outer surface of the muscle fiber inside to the myofibrils?

Each skeletal muscle cell constitutes a single

The primary reservoir for calcium that is released during excitation-contraction coupling in a skeletal muscle fiber is the

The thick filament is composed almost entirely of _____ molecules.