Chapter 9 Part 9 (multiple choice) Flashcards Preview

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Flashcards in Chapter 9 Part 9 (multiple choice) Deck (25):
1

What is the role of tropomyosin in skeletal muscles?
A) Tropomyosin is the chemical that activates the myosin heads.
B) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
C) Tropomyosin is the receptor for the motor neuron neurotransmitter.
D) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

D) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

2

Which muscle cells have the greatest ability to regenerate?
A) smooth
B) no muscle can regenerate
C) cardiac
D) skeletal

A) smooth

3

Most skeletal muscles contain ________.
A) a predominance of fast oxidative fibers
B) a mixture of fiber types
C) a predominance of slow oxidative fibers
D) muscle fibers of the same type

B) a mixture of fiber types

4

Fatigued muscle cells that recover rapidly are the products of ________.
A) slow exercise of long duration
B) slow exercise of short duration
C) intense exercise of long duration
D) intense exercise of short duration

D) intense exercise of short duration

5

The strongest muscle contractions are normally achieved by ________.
A) recruiting small and medium muscle fibers
B) increasing stimulus above the treppe stimulus
C) increasing the stimulation up to the maximal stimulus
D) increasing stimulus above the threshold

C) increasing the stimulation up to the maximal stimulus

6

Which of the following would be recruited later in muscle stimulation when contractile strength increases?
A) large motor units with small, highly excitable neurons
B) many small motor units with the ability to stimulate other motor units
C) motor units with larger, less excitable neurons
D) motor units with the longest muscle fibers

C) motor units with larger, less excitable neurons

7

Excitation-contraction coupling requires which of the following substances?
A) ATP only
B) Ca2+ and ATP
C) Ca2+ only
D) ATP and glucose

B) Ca2+ and ATP

8

Which of the following is a factor that affects the velocity and duration of muscle contraction?
A) number of muscle fibers stimulated
B) load on the fiber
C) size of the muscle fibers stimulated
D) muscle length

B) load on the fiber

9

Myoglobin ________.
A) is a protein involved in the direct phosphorylation of ADP
B) produces the end plate potential
C) stores oxygen in muscle cells
D) breaks down glycogen

C) stores oxygen in muscle cells

10

What structure in skeletal muscle cells functions in calcium storage?
A) sarcoplasmic reticulum
B) mitochondria
C) myofibrillar network
D) intermediate filament network

A) sarcoplasmic reticulum

11

What does excess postexercise oxygen consumption represent?
A) the amount of oxygen taken into the body immediately after the exertion
B) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
C) the amount of oxygen equal to the oxygen already used
D) amount of oxygen needed for aerobic activity to accomplish the same amount of work

What does excess postexercise oxygen consumption represent?

B) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used

12

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.
A) contraction
B) latent
C) relaxation
D) refractory

B) latent

13

Creatine phosphate functions in the muscle cell by ________.
A) inducing a conformational change in the myofilaments
B) forming a temporary chemical compound with myosin
C) storing energy that will be transferred to ADP to resynthesize ATP
D) forming a chemical compound with actin

C) storing energy that will be transferred to ADP to resynthesize ATP

14

What is the primary function of wave summation?
A) prevent muscle fatigue
B) prevent muscle relaxation
C) increase muscle tension
D) produce smooth, continuous muscle contraction

D) produce smooth, continuous muscle contraction

15

The major function of the sarcoplasmic reticulum in muscle contraction is to ________.
A) make and store phosphocreatine
B) provide a source of myosin for the contraction process
C) synthesize actin and myosin myofilaments
D) regulate intracellular calcium concentration

D) regulate intracellular calcium concentration

16

What produces the striations of a skeletal muscle cell?
A) the sarcoplasmic reticulum
B) a difference in the thickness of the sarcolemma
C) the arrangement of myofilaments
D) the T tubules

C) the arrangement of myofilaments

17

During muscle contraction, myosin cross bridges attach to which active sites?
A) Z discs
B) actin filaments
C) myosin filaments
D) thick filaments

B) actin filaments

18

Which of the following surrounds the individual muscle cell?
A) fascicle
B) endomysium
C) perimysium
D) epimysium

B) endomysium

19

Rigor mortis occurs because ________.
A) no ATP is available to release attached actin and myosin
molecules
B) proteins are beginning to break down, thus preventing a flow of calcium ions
C) sodium ions leak into the muscle causing continued contractions
D) the cells are dead

A) no ATP is available to release attached actin and myosin
molecules

20

Which of the choices below does not describe how excess postexercise oxygen consumption (oxygen deficit) restores metabolic conditions?
A) converts lactic acid back into glycogen stores in the liver
B) replaces the oxygen removed from myoglobin
C) increases the level of lactic acid in the muscle
D) resynthesizes creatine phosphate and ATP in muscle fibers

C) increases the level of lactic acid in the muscle

21

The term aponeurosis refers to ________.
A) a sheetlike indirect attachment to a skeletal element
B) the tropomyosin-troponin complex
C) the rough endoplasmic reticulum
D) the bands of myofibrils

A) a sheetlike indirect attachment to a skeletal element

22

The oxygen-binding protein found in muscle cells is ________.
A) immunoglobin
B) ATP
C) myoglobin
D) hemoglobin

C) myoglobin

23

The contractile units of skeletal muscles are ________.
A) T tubules
B) mitochondria
C) microtubules
D) myofibrils

D) myofibrils

24

What is the functional unit of a skeletal muscle called?
A) a sarcomere
B) a myofilament
C) the sarcoplasmic reticulum
D) a myofibril

A) a sarcomere

25

What is the functional role of the T tubules?
A) hold cross bridges in place in a resting muscle
B) enhance cellular communication during muscle contraction
C) stabilize the G and F actin
D) synthesize ATP to provide energy for muscle contraction

B) enhance cellular communication during muscle contraction