Question 1

What is the contraction of skeletal muscles based on?

Accepted Answer

A)  actin filaments coiling up to become shorter 
B)  myosin cross- bridges binding to actin and undergoing a power stroke 
C)  myosin filaments coiling up to become shorter 
D)  actin cross- bridges binding to myosin and undergoing a power stroke 
E)  actin and myosin filaments both coiling up to become shorter 
A)  actin filaments coiling up to become shorter 
B)  myosin cross- bridges binding to actin and undergoing a power stroke 
C)  myosin filaments coiling up to become shorter 
D)  actin cross- bridges binding to myosin and undergoing a power stroke 
E)  actin and myosin filaments both coiling up to become shorter B

Question 2

In a relaxed skeletal muscle

Accepted Answer

A)  thick and thin filaments overlap to the greatest extent possible. 
B)  the Z lines are farthest apart. 
C)  calcium is bound to tropinin. 
D)  sarcomeres are at their shortest length. 
E)  calcium is released from the sarcoplasmic reticulum. 
A)  thick and thin filaments overlap to the greatest extent possible. 
B)  the Z lines are farthest apart. 
C)  calcium is bound to tropinin. 
D)  sarcomeres are at their shortest length. 
E)  calcium is released from the sarcoplasmic reticulum. B

Question 3

Food moves along the digestive tract as the result of contractions by which muscle type?

Accepted Answer

A)  skeletal muscle 
B)  smooth muscle 
C)  voluntary muscle 
D)  cardiac muscle 
E)  striated muscle 
A)  skeletal muscle 
B)  smooth muscle 
C)  voluntary muscle 
D)  cardiac muscle 
E)  striated muscle B

Question 4

What do the calcium ions released into the cytosol during excitation of skeletal muscle bind to?

Accepted Answer

A)  actin 
B)  troponin complex 
C)  myosin 
D)  transverse tubules 
A)  actin 
B)  troponin complex 
C)  myosin 
D)  transverse tubules

Question 5

Which muscle types) is/are involuntary?

Accepted Answer

A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac and skeletal muscle 
D)  smooth and cardiac muscle 
E)  cardiac muscle 
A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac and skeletal muscle 
D)  smooth and cardiac muscle 
E)  cardiac muscle

Question 6

During the contraction of a vertebrate skeletal muscle fibre, calcium ions

Accepted Answer

A)  reestablish the polarization of the plasma membrane following an action potential. 
B)  transmit action potentials from the motor neuron to the muscle fibre. 
C)  break cross- bridges by acting as a cofactor in the hydrolysis of ATP. 
D)  bind with troponin, causing its shape to change so that the myosin- binding sites on actin are exposed. 
E)  spread action potentials through the T tubules. 
A)  reestablish the polarization of the plasma membrane following an action potential. 
B)  transmit action potentials from the motor neuron to the muscle fibre. 
C)  break cross- bridges by acting as a cofactor in the hydrolysis of ATP. 
D)  bind with troponin, causing its shape to change so that the myosin- binding sites on actin are exposed. 
E)  spread action potentials through the T tubules.

Question 7

How does skeletal muscle return to its starting length after a contraction?

Accepted Answer

A)  Antagonistic muscles work to lengthen a given muscle once it relaxes. 
B)  It lengthens itself by reversing the contraction process. 
C)  Ligaments bind muscles together. 
D)  It undergoes recoil due to the elastic properties of tendons. 
A)  Antagonistic muscles work to lengthen a given muscle once it relaxes. 
B)  It lengthens itself by reversing the contraction process. 
C)  Ligaments bind muscles together. 
D)  It undergoes recoil due to the elastic properties of tendons.

Question 8

Use the following information when answering the corresponding questions).
"Marine cone snails from the genus Conus are estimated to consist of up to 700 species. These predatory molluscs have devised an efficient venom apparatus that allows them to successfully capture polychaete worms, other molluscs or, in some cases, fish as their primary food sources. … conotoxins from Australian species of Conus … have the capacity to inhibit specifically the nicotinic acetylcholine receptors in higher animals." B. G. Livett, K. R. Gayler, and Z. Khalil. 2004. Drugs from the sea: Conopeptides as potential therapeutics. Current Medicinal Chemistry 11:1715-23.)
-This particular conotoxin inhibits acetylcholine receptors that are located

Accepted Answer

A)  on motor neuron dendrites. 
B)  on the postsynaptic membrane, on the muscle cell. 
C)  along the motor neuron axon. 
D)  on the presynaptic membrane of the neuromuscular junction. 
A)  on motor neuron dendrites. 
B)  on the postsynaptic membrane, on the muscle cell. 
C)  along the motor neuron axon. 
D)  on the presynaptic membrane of the neuromuscular junction.

Question 9

Skeletal muscle contraction begins when calcium ions bind to

Accepted Answer

A)  energized cross- bridges. 
B)  actin. 
C)  myosin. 
D)  troponin. 
E)  acetylcholine receptors. 
A)  energized cross- bridges. 
B)  actin. 
C)  myosin. 
D)  troponin. 
E)  acetylcholine receptors.

Question 10

Compared with slow oxidative muscle fibres, those classified as fast glycolytic fibres typically have

Accepted Answer

A)  a higher density of mitochondria. 
B)  a higher concentration of myoglobin. 
C)  a darker visual appearance. 
D)  less resistance to fatigue. 
E)  a smaller diameter. 
A)  a higher density of mitochondria. 
B)  a higher concentration of myoglobin. 
C)  a darker visual appearance. 
D)  less resistance to fatigue. 
E)  a smaller diameter.

Question 11

Motor neurons release the neurotransmitter acetylcholine ACh), and acetylcholinesterase degrades ACh in the synapse. If a neurophysiologist applies onchidal a naturally occurring acetylcholinesterase inhibitor produced by the mollusk Onchidella binneyi) to a synapse, what would you expect to happen?

Accepted Answer

A)  gradual loss of resting potential 
B)  decrease in the frequency of action potentials 
C)  paralysis of muscle tissue 
D)  convulsions due to constant muscle stimulation 
E)  no effect 
A)  gradual loss of resting potential 
B)  decrease in the frequency of action potentials 
C)  paralysis of muscle tissue 
D)  convulsions due to constant muscle stimulation 
E)  no effect

Question 12

R. McNeill Alexander demonstrated that tendons improve the efficiency of running by

Accepted Answer

A)  generating force to relengthen muscle once it relaxes. 
B)  acting like a stiff rod and communicating force without stretching. 
C)  connecting bones to bones and keeping the skeleton intact. 
D)  storing and releasing energy like a spring with each step. 
A)  generating force to relengthen muscle once it relaxes. 
B)  acting like a stiff rod and communicating force without stretching. 
C)  connecting bones to bones and keeping the skeleton intact. 
D)  storing and releasing energy like a spring with each step.

Question 13

A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help?

Accepted Answer

A)  Depolarize the motor neurons to send an action potential to the muscle cells. 
B)  Increase the amount of acetylcholine at the synapses between motor neurons and muscle cells. 
C)  Induce tropomyosin and troponin to bind to the myosin binding sites on actin. 
D)  Inject calcium into the muscle cell because it is not being released from the sarcoplasmic reticulum. 
A)  Depolarize the motor neurons to send an action potential to the muscle cells. 
B)  Increase the amount of acetylcholine at the synapses between motor neurons and muscle cells. 
C)  Induce tropomyosin and troponin to bind to the myosin binding sites on actin. 
D)  Inject calcium into the muscle cell because it is not being released from the sarcoplasmic reticulum.

Question 14

Among these choices, the most energetically efficient locomotion per unit mass is likely to be which of the following?

Accepted Answer

A)  running by a 40- kilogram ungulate 
B)  flying by a 100- gram bird 
C)  swimming by a 10- gram minnow bony fish) 
D)  swimming by a 100- kilogram tuna bony fish) 
E)  running by a 50- gram rodent 
A)  running by a 40- kilogram ungulate 
B)  flying by a 100- gram bird 
C)  swimming by a 10- gram minnow bony fish) 
D)  swimming by a 100- kilogram tuna bony fish) 
E)  running by a 50- gram rodent

Question 15

The functions of the vertebrate skeleton include which of the following?
I. maintenance of body posture
II. calcium homeostasis
III. transfer of muscle forces

Accepted Answer

A)  III 
B)  I and II 
C)  I, II, and III 
D)  I and III 
E)  II and III 
A)  III 
B)  I and II 
C)  I, II, and III 
D)  I and III 
E)  II and III

Question 16

When an action potential from a motor neuron arrives at the neuromuscular junction NMJ), a series of events occurs that leads to muscle contraction. Which of the following events will occur last i.e., after all of the others)?

Accepted Answer

A)  release of Ca++ from the sarcoplasmic reticulum 
B)  depolarization of the muscle cell 
C)  ACh release 
D)  conformational change in troponin 
E)  action potential propagation down the T- tubules 
A)  release of Ca++ from the sarcoplasmic reticulum 
B)  depolarization of the muscle cell 
C)  ACh release 
D)  conformational change in troponin 
E)  action potential propagation down the T- tubules

Question 17

What would be the effect on muscle contraction if troponin were experimentally altered to no longer interact with tropomyosin, so the complex could no longer bind to actin?

Accepted Answer

A)  Muscle contraction would be weakened, but would still occur as long as tropomyosin is functional. 
B)  Muscle contraction could no longer occur. 
C)  Muscles could not relax after contraction. 
D)  ATP could not be hydrolyzed by enzymes in the muscle. 
A)  Muscle contraction would be weakened, but would still occur as long as tropomyosin is functional. 
B)  Muscle contraction could no longer occur. 
C)  Muscles could not relax after contraction. 
D)  ATP could not be hydrolyzed by enzymes in the muscle.

Question 18

What is the best explanation for why elephants stand with a more upright posture and have relatively thicker bones than cats?

Accepted Answer

A)  Cats and elephants are from different taxonomic groups and therefore differ in appearance. 
B)  Cats are smaller and need to run faster; therefore, they have smaller bones and a crouching posture. 
C)  Because they have a much greater volume, elephants require a disproportionately larger cross- sectional area of their bones than cats. 
D)  Cats eat meat and elephants eat plants, requiring different bodies. 
A)  Cats and elephants are from different taxonomic groups and therefore differ in appearance. 
B)  Cats are smaller and need to run faster; therefore, they have smaller bones and a crouching posture. 
C)  Because they have a much greater volume, elephants require a disproportionately larger cross- sectional area of their bones than cats. 
D)  Cats eat meat and elephants eat plants, requiring different bodies.

Question 19

Compared with parallel muscles, pennate muscles

Accepted Answer

A)  produce less force and undergo greater shortening. 
B)  produce more force and undergo greater shortening. 
C)  produce less force and undergo less shortening. 
D)  produce more force and undergo less shortening. 
A)  produce less force and undergo greater shortening. 
B)  produce more force and undergo greater shortening. 
C)  produce less force and undergo less shortening. 
D)  produce more force and undergo less shortening.

Question 20

What is an explanation for the pectoral or breast meat of ducks being very dark in colour?

Accepted Answer

A)  Ducks employ intermediate muscle fibres for swimming and flying. 
B)  Ducks use their wings for very short flights and need fast muscle fibres to power their take- offs. 
C)  Ducks fly long distances and need myoglobin- rich slow muscle fibres to power high- endurance flights. 
D)  Ducks are primarily swimmers and therefore do not need breast muscles full of "white meat." 
A)  Ducks employ intermediate muscle fibres for swimming and flying. 
B)  Ducks use their wings for very short flights and need fast muscle fibres to power their take- offs. 
C)  Ducks fly long distances and need myoglobin- rich slow muscle fibres to power high- endurance flights. 
D)  Ducks are primarily swimmers and therefore do not need breast muscles full of "white meat."

Exam 45: Animal Movement

What is the contraction of skeletal muscles based on?

In a relaxed skeletal muscle

Food moves along the digestive tract as the result of contractions by which muscle type?

What do the calcium ions released into the cytosol during excitation of skeletal muscle bind to?

Which muscle types) is/are involuntary?

During the contraction of a vertebrate skeletal muscle fibre, calcium ions

How does skeletal muscle return to its starting length after a contraction?

Skeletal muscle contraction begins when calcium ions bind to

Compared with slow oxidative muscle fibres, those classified as fast glycolytic fibres typically have

R. McNeill Alexander demonstrated that tendons improve the efficiency of running by

A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help?

Among these choices, the most energetically efficient locomotion per unit mass is likely to be which of the following?

The functions of the vertebrate skeleton include which of the following? I. maintenance of body posture II. calcium homeostasis III. transfer of muscle forces

When an action potential from a motor neuron arrives at the neuromuscular junction NMJ), a series of events occurs that leads to muscle contraction. Which of the following events will occur last i.e., after all of the others)?

What would be the effect on muscle contraction if troponin were experimentally altered to no longer interact with tropomyosin, so the complex could no longer bind to actin?

What is the best explanation for why elephants stand with a more upright posture and have relatively thicker bones than cats?

Compared with parallel muscles, pennate muscles

What is an explanation for the pectoral or breast meat of ducks being very dark in colour?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Gene Structure and Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

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