Question 1

The structure enabling depolarization to travel deep into the muscle fiber is the ______.

Accepted Answer

A) sarcomere 
B) motor unit 
C) T tubule 
D) sarcoplasmic reticulum 
A) sarcomere 
B) motor unit 
C) T tubule 
D) sarcoplasmic reticulum C

Question 2

Insects such as mosquitoes and beetles can beat their wings at tremendous speeds.This can be accomplished because

Accepted Answer

A) their wing muscle contractions causes another set of muscles to stretch which in turn produces another contraction without waiting for the arrival of a nerve impulse. 
B) their wing muscle contractions cause another set of muscles to relax which in turn produces another wing movement. 
C) their wing muscle contractions are stimulated by the continuous nerve signal impulses which produce a continuous contraction of their wing muscles. 
D) their wing muscle contractions are capable of producing more ATP which allows these insects to have much faster and sustained wing movements. 
A) their wing muscle contractions causes another set of muscles to stretch which in turn produces another contraction without waiting for the arrival of a nerve impulse. 
B) their wing muscle contractions cause another set of muscles to relax which in turn produces another wing movement. 
C) their wing muscle contractions are stimulated by the continuous nerve signal impulses which produce a continuous contraction of their wing muscles. 
D) their wing muscle contractions are capable of producing more ATP which allows these insects to have much faster and sustained wing movements. A

Question 3

Based on the above diagram and other information from your text, what is the most likely (e.g., most parsimonious) explanation for the evolution of flight in vertebrates?

Accepted Answer

A) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats, in pterosaurs and in the common ancestor of birds and dinosaurs. 
B) Wings evolved once in vertebrates (e.g., the common ancestor of all terrestrial vertebrates had wings) and wings were subsequently lost in all but three lineages: bats, pterosaurs and birds. 
C) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats, in pterosaurs and in birds. 
D) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently two different times: once in bats and once in the common ancestor of birds, pterosaurs and dinosaurs. 
A) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats, in pterosaurs and in the common ancestor of birds and dinosaurs. 
B) Wings evolved once in vertebrates (e.g., the common ancestor of all terrestrial vertebrates had wings) and wings were subsequently lost in all but three lineages: bats, pterosaurs and birds. 
C) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats, in pterosaurs and in birds. 
D) The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently two different times: once in bats and once in the common ancestor of birds, pterosaurs and dinosaurs. C

Question 4

Impulses conducted along the muscle fiber's transverse tubules stimulate the release of calcium ions into the cytoplasm

Accepted Answer

A) from the Z line. 
B) from the actin and myosin subunits. 
C) from the troponin. 
D) from the sarcoplasmic reticulum. 
A) from the Z line. 
B) from the actin and myosin subunits. 
C) from the troponin. 
D) from the sarcoplasmic reticulum.

Question 5

You decide to do an experiment with isolated myofibrils to explore the effects of ATP hydrolysis on myofibril function.You do this by bathing the myofibrils in a solution that contains a modified form of ATP, which cannot be split into ADP and Pi. At what step will myofibril function be arrested by using this compound instead of unmodified ATP?

Accepted Answer

A) Myosin heads will be unable to bind to the actin filaments. 
B) There will be no block in the cycle, since ATP hydrolysis is not required for this process. 
C) The myosin heads will remain attached to the actin filaments after the power stroke. 
D) Myosin heads will bind to the actin filaments, but the power stroke will not occur and actin filaments will not slide over the myosin filaments. 
A) Myosin heads will be unable to bind to the actin filaments. 
B) There will be no block in the cycle, since ATP hydrolysis is not required for this process. 
C) The myosin heads will remain attached to the actin filaments after the power stroke. 
D) Myosin heads will bind to the actin filaments, but the power stroke will not occur and actin filaments will not slide over the myosin filaments.

Question 6

According to the figure, which one represents the muscle in an optimal condition for a strong contraction?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 7

All of the following statements about exoskeletons are correct EXCEPT

Accepted Answer

A) exoskeletons are made of chitin. 
B) muscles are attached to the exoskeleton. 
C) exoskeletons do not limit growth because they can stretch. 
D) exoskeletons are shed by many arthropods in a process called molting. 
A) exoskeletons are made of chitin. 
B) muscles are attached to the exoskeleton. 
C) exoskeletons do not limit growth because they can stretch. 
D) exoskeletons are shed by many arthropods in a process called molting.

Question 8

Which of the following is/are required with actin and myosin in order to initiate muscle contraction?

Accepted Answer

A) ATP 
B) calcium and phosphate 
C) phosphate 
D) calcium and ATP 
A) ATP 
B) calcium and phosphate 
C) phosphate 
D) calcium and ATP

Question 9

A muscle fiber contracts by a sequence of events initiated by the binding of acetylcholine to its receptor.Which of the following is the correct sequence? I-The calcium-troponin complex pulls tropomyosin away from the myosin binding sites of actin.II-The freed-sites of actin bind to myosin to form cross bridges.III-Calcium ion binds to the troponin.

Accepted Answer

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

Question 10

Imagine an earthworm that has no chaetae.How would the lack of chaetae affect movement of the earthworm?

Accepted Answer

A) The earthworm would have difficulty changing locations, since it cannot anchor itself in the soil. 
B) The earthworm would be much flatter than normal since it has no hydrostatic skeleton. 
C) The earthworm would only be able to extend its body segments. 
D) The earthworm would only be able to shorten its body segments. 
A) The earthworm would have difficulty changing locations, since it cannot anchor itself in the soil. 
B) The earthworm would be much flatter than normal since it has no hydrostatic skeleton. 
C) The earthworm would only be able to extend its body segments. 
D) The earthworm would only be able to shorten its body segments.

Question 11

The masseter muscles originate on your cheekbones and insert into the posterior corners of the mandible (the lower jaw bone) underneath your ears.Will contraction of the masseter muscles open or close your jaw?

Accepted Answer

A) open 
B) close 
A) open 
B) close

Question 12

The figure below represents a joint in the hind leg of a grasshopper.The exoskeleton of the leg is indicated by the two pairs of parallel black lines.A muscle that moves this leg is fixed to the skeleton at the end marked with a blue star.When the muscle contracts, it will pull on the tendon at its opposite end.Which configuration shows the most likely arrangement of the exoskeleton and a muscle that increases the flexion of this leg?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 13

Which of the following regarding the Haversian System is false?

Accepted Answer

A) Haversian canals may contain nerve fibers. 
B) Haversian canals run parallel to the length of long bone. 
C) Haversian canals are created by osteoclasts that tunnel through the bone matrix. 
D) It keeps osteocytes alive. 
A) Haversian canals may contain nerve fibers. 
B) Haversian canals run parallel to the length of long bone. 
C) Haversian canals are created by osteoclasts that tunnel through the bone matrix. 
D) It keeps osteocytes alive.

Question 14

Which of the bone development lineages is incorrect?

Accepted Answer

A) white blood cell progenitors $\rightarrow$ monocytes $\rightarrow$ osteoclast 
B) undifferentiated mesenchymal cells $\rightarrow$osteocyte $\rightarrow$ osteoblast 
C) undifferentiated mesenchymal cells $\rightarrow$fibroblast $\rightarrow$ collagen 
D) undifferentiated mesenchymal cells $\rightarrow$ chondroblast $\rightarrow$ chondrocyte 
A) white blood cell progenitors $\rightarrow$ monocytes $\rightarrow$ osteoclast 
B) undifferentiated mesenchymal cells $\rightarrow$osteocyte $\rightarrow$ osteoblast 
C) undifferentiated mesenchymal cells $\rightarrow$fibroblast $\rightarrow$ collagen 
D) undifferentiated mesenchymal cells $\rightarrow$ chondroblast $\rightarrow$ chondrocyte

Question 15

In order for a muscle to contract, calcium ions released from the sarcoplasmic reticulum must bind to

Accepted Answer

A) troponin. 
B) myosin. 
C) tropomyosin. 
D) ATP. 
A) troponin. 
B) myosin. 
C) tropomyosin. 
D) ATP.

Question 16

The use-dependent decrease in the ability of a muscle to generate force is called _____.

Accepted Answer

A) tetanus 
B) aerobic fitness 
C) fatigue 
D) endurance 
A) tetanus 
B) aerobic fitness 
C) fatigue 
D) endurance

Question 17

Utilizing more motor units for stronger muscle contractions is called

Accepted Answer

A) fast-twitching. 
B) fatigue. 
C) aerobic capacity. 
D) recruitment. 
A) fast-twitching. 
B) fatigue. 
C) aerobic capacity. 
D) recruitment.

Question 18

A lab technician is preparing to dispose of a rat and a frog that were euthanized earlier in the day for a scientific study.Although the two animals died at the same time, the rat has rigor mortis while the frog does not yet show any signs of it.What is the best explanation for this time difference in the onset of rigor mortis?

Accepted Answer

A) The rat has higher concentrations of myoglobin in its muscles than the frog. 
B) All the frog's muscles are fast-twitch muscles. 
C) The rat's muscles have a greater density of myofilaments than the frog's muscles. 
D) The frog has lower concentrations of glycogen in its muscles than the rat. 
A) The rat has higher concentrations of myoglobin in its muscles than the frog. 
B) All the frog's muscles are fast-twitch muscles. 
C) The rat's muscles have a greater density of myofilaments than the frog's muscles. 
D) The frog has lower concentrations of glycogen in its muscles than the rat.

Question 19

Which of the following regarding bone growth is false?

Accepted Answer

A) Cartilage of growth plates actively grow in lengthwise direction. 
B) Increase in bone thickness results from the adding of bone layers on top of the periosteum. 
C) Some cartilage remains after it is replaced by bone. 
D) Cartilage calcification encroaches on the cartilaginous growth plate. 
A) Cartilage of growth plates actively grow in lengthwise direction. 
B) Increase in bone thickness results from the adding of bone layers on top of the periosteum. 
C) Some cartilage remains after it is replaced by bone. 
D) Cartilage calcification encroaches on the cartilaginous growth plate.

Question 20

A cross bridge is the binding of which two proteins?

Accepted Answer

A) actin and myosin 
B) actin and troponin 
C) myosin and troponin 
D) collagen and troponin 
A) actin and myosin 
B) actin and troponin 
C) myosin and troponin 
D) collagen and troponin

Exam 46: The Musculoskeletal System

The structure enabling depolarization to travel deep into the muscle fiber is the ______.

Insects such as mosquitoes and beetles can beat their wings at tremendous speeds.This can be accomplished because

Based on the above diagram and other information from your text, what is the most likely (e.g., most parsimonious) explanation for the evolution of flight in vertebrates?

Impulses conducted along the muscle fiber's transverse tubules stimulate the release of calcium ions into the cytoplasm

According to the figure, which one represents the muscle in an optimal condition for a strong contraction?

All of the following statements about exoskeletons are correct EXCEPT

Which of the following is/are required with actin and myosin in order to initiate muscle contraction?

Imagine an earthworm that has no chaetae.How would the lack of chaetae affect movement of the earthworm?

The masseter muscles originate on your cheekbones and insert into the posterior corners of the mandible (the lower jaw bone) underneath your ears.Will contraction of the masseter muscles open or close your jaw?

Which of the following regarding the Haversian System is false?

Which of the bone development lineages is incorrect?

In order for a muscle to contract, calcium ions released from the sarcoplasmic reticulum must bind to

The use-dependent decrease in the ability of a muscle to generate force is called _____.

Utilizing more motor units for stronger muscle contractions is called

Which of the following regarding bone growth is false?

A cross bridge is the binding of which two proteins?

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