BIO 234 – Which of the following are composed of myosin

10 Jun BIO 234 – Which of the following are composed of myosin

Question
101) Which of the following are composed of myosin?

A) thick filaments

B) thin filaments

C) all myofilaments

D) Z discs

Answer:

102) During muscle contraction, myosin cross bridges attach to which active sites?

A) myosin filaments

B) actin filaments

C) Z discs

D) thick filaments

Answer:

103) Which of the following surrounds the individual muscle cell?

A) perimysium

B) endomysium

C) epimysium

D) fascicle

Answer:

104) Smooth muscles that act like skeletal muscles but are controlled by autonomic nerves and

hormones are ________.

A) single-unit muscles

B) multiunit muscles

C) red muscles

D) white muscles

Answer:

105) Rigor mortis occurs because ________.

A) the cells are dead

B) sodium ions leak out of the muscle

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

D) proteins are beginning to break down, thus preventing a flow of calcium ions

Answer:

106) Which of the following does not act as a stimulus to initiate a muscle contraction?

A) hormonal activity

B) neurotransmitters

C) a change in the pH of a muscle

D) a change of temperature

Answer:

107) The term aponeurosis refers to ________.

A) the bands of myofibrils

B) a sheetlike indirect attachment to a skeletal element

C) the rough endoplasmic reticulum

D) the tropomyosin-troponin complex

Answer:

108) The oxygen-binding protein found in muscle cells is ________.

A) hemoglobin

B) ATP

C) myoglobin

D) immunoglobin

Answer:

109) The contractile units of skeletal muscles are ________.

A) microtubules

B) mitochondria

C) T tubules

D) myofibrils

Answer:

110) The site of calcium regulation in the smooth muscle cell is ________.

A) actin

B) troponin

C) myosin

D) calmodulin

Answer:

111) One functional unit of a skeletal muscle is ________.

A) a sarcomere

B) a myofilament

C) a myofibril

D) the sarcoplasmic reticulum

Answer:

112) The functional role of the T tubules is to ________.

A) stabilize the G and F actin

B) enhance cellular communication during muscle contraction

C) hold cross bridges in place in a resting muscle

D) synthesize ATP to provide energy for muscle contraction

Answer:

113) The role of calcium ions in muscle contraction is to ________.

A) act as a third messenger

B) reestablish glycogen stores

C) bind to regulatory sites on troponin, changing the configuration

D) initiate the conversion of carbon dioxide to oxygen for storage

Answer:

114) The warm-up period required of athletes in order to bring their muscles to peak performance

is called ________.

A) twitch

B) wave summation

C) treppe

D) incomplete tetanus

Answer:

115) The main effect of the warm-up period of athletes, as the muscle contractions increase in

strength, is to ________.

A) increase the myoglobin content

B) convert glycogen to glucose

C) tone the muscles and stabilize the joints for the workout

D) enhance the availability of calcium and the efficiency of enzyme systems

Answer:

116) During vigorous excercise, there may be insufficient oxygen available to completely break

down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.

A) a strong base

B) stearic acid

C) hydrochloric acid

D) lactic acid

Answer:

117) When a muscle is unable to respond to stimuli temporarily, it is in which of the following

periods?

A) relaxation period

B) refractory period

C) latent period

D) fatigue period

Answer:

118) In an isotonic contraction, the muscle ________.

A) changes in length and moves the ?load?

B) does not change in length but increases tension

C) never converts pyruvate to lactate

D) rapidly resynthesizes creatine phosphate and ATP

Answer:

119) The muscle cell membrane is called the ________.

A) endomysium

B) sarcolemma

C) perimysium

D) epimysium

Answer:

120) Smooth muscle is significantly different from striated muscle in several ways. Which of the

following is true?

A) Smooth muscle has transverse tubules.

B) Smooth muscle is larger and more powerful than striated muscle.

C) The fibers of smooth muscle are arranged quadrangularly.

D) Smooth muscle contracts in a twisting way.

Answer: D

121) The mechanism of contraction in smooth muscle is different from skeletal muscle in that

________.

A) actin and myosin interact by the sliding filament mechanism

B) the trigger for contraction is a rise in intracellular calcium

C) the site of calcium regulation differs

D) ATP energizes the sliding process

Answer:

122) The cells of single-unit visceral muscle ________.

A) contract all at once

B) are chemically coupled to one another by gap junctions

C) exhibit spontaneous action potentials

D) consist of muscle fibers that are structurally independent of each other

Answer:

123) Which of the following statements is not true concerning developmental aspects of muscle?

A) There is no biological basis for the difference in strength between women and men.

B) Skeletal muscle is derived from mesoderm.

C) Skeletal muscle develops from somites.

D) Most muscle tissues develop from myoblasts.

Answer:

124) Which of the following is true about smooth muscle contraction?

A) Certain smooth muscle cells can actually divide to increase their numbers.

B) Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any

connective tissue elements.

C) Smooth muscle cannot stretch as much as skeletal muscle.

D) Smooth muscle has well-developed T tubules at the site of invagination.

Answer:

125) Smooth muscle is characterized by all of the following except ________.

A) it appears to lack troponin

B) there are more thick filaments than thin filaments

C) there are no sarcomeres

D) there are noncontractile intermediate filaments that attach to dense bodies within the cell

Answer:

126) Muscle tissue has all of the following properties except ________.

A) secretion

B) contractility

C) extensibility

D) excitability

Answer:

127) The giant protein titin maintains the organization of the ________ assisting in muscle

stretching.

A) A band

B) I band

C) Z disc

D) M line

Answer:

128) Which of the following statements is true?

A) Cardiac muscle cells have many nuclei.

B) Smooth muscle cells have T tubules.

C) Striated muscle cells are long and cylindrical with many nuclei.

D) Cardiac muscle cells are found in the heart and large blood vessels.

Answer:

129) An anaerobic metabolic pathway that results in the production of two net ATPs per glucose

plus two pyruvic acid molecules is ________.

A) the citric acid cycle

B) glycolysis

C) hydrolysis

D) the electron transport chain

Answer:

130) Muscle tone is ________.

A) the ability of a muscle to efficiently cause skeletal movements

B) the feeling of well-being following exercise

C) a state of sustained partial contraction

D) the condition of athletes after intensive training

Answer:

131) The sliding filament model of contraction involves ________.

A) actin and myosin sliding past each other and partially overlap

B) the shortening of thick filaments so that thin filaments slide past

C) actin and myosin shortening but not sliding past each other

D) the Z discs sliding over the myofilaments

Answer:

132) After nervous stimulation stops, ACh in the synaptic cleft is prevented from continuing

stimulation of contraction by ________.

A) calcium ions returning to the terminal cisternae

B) the tropomyosin blocking the myosin once full contraction is achieved

C) acetylcholinesterase destroying the ACh

D) the action potential stopped going down the overloaded T tubules

Answer:

133) Which of the following is most accurate?

A) Muscle tension remains relatively constant during isotonic contraction.

B) T-tubles may be sliding during isotonic contraction.

C) The I band lenghtens during isotonic contraction.

D) Myofilaments slide during isometric contractions.

Answer:

134) The most distinguishing characteristic of muscle tissue is ________.

A) the design of the fibers

B) the sarcoplasmic reticulum

C) the diversity of activity of muscle tissue

D) the ability to transform chemical energy into mechanical energy

Answer:

135) Three discrete types of muscle fibers are identified on the basis of their size, speed, and

endurance. Which of the following athletic endeavors best represents the use of red fibers?

A) a sprint by an Olympic runner

B) a long, relaxing swim

C) playing baseball or basketball

D) mountain climbing

Answer:

136) Of the following muscle types, which has only one nucleus, no sarcomeres, and rare gap

junctions?

A) visceral smooth muscle

B) multiunit smooth muscle

C) cardiac muscle

D) skeletal muscle

Answer:

137) Hypothetically, if a muscle were stretched to the point where thick and thin filaments no

longer overlapped ________.

A) cross bridge attachment would be optimum because of all the free binding sites on actin

B) no muscle tension could be generated

C) maximum force production would result since the muscle has a maximum range of

travel

D) ATP consumption would increase since the sarcomere is ?trying? to contract

Answer:

138) An individual has just ingested a chemical that binds irreversibly to the ACh receptors in the

sarcolemma. By itself it does not alter membrane potential, yet prevents normal

neurotransmitter binding. Ignoring the effects on any other system, the consequence to skeletal

muscle would be ________.

A) irreversible contraction as soon as the first nervous stimulation reached the sarcolemma

B) no contraction at all by nervous mechanisms

C) contraction if stimulated by an external electrode

D) no contraction at all by nervous mechanisms, but contraction if stimulated by an external

electrode