BIOS 251 FINAL EXAM -25 ACTUAL EXAM

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BIOS 251 FINAL EXAM -25 ACTUAL EXAM

QUESTIONS WITH COERRECT ANSWERS

(SUMMER-FALL SESSION GRADED A+)

16) Which of the following functions as a motor protein in all three types of muscle tissue?

• actin
• myosin
• troponin
• titin
• tropomyosin - ANSWER>>b) myosin

17) What regulatory proteins can be found in the thin filaments of skeletal muscle fibers?

• troponin and titin
• tropomyosin and troponin
• myosin and titin
• titin and tropomyosin
• tropomyosin and myosin - ANSWER>>b) tropomyosin and troponin

18) Which of the regions of a sarcomere contain titin? 1 / 3

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• the A band only
• the H zone only
• the zone of overlap only
• from M line to Z disc
• the I band only - ANSWER>>d) from M line to Z disc

19) Which of the following proteins is used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons?

• troponin
• tropomyosin
• myosin
• actin
• dystrophin - ANSWER>>e) dystrophin

20) During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the

a) Z disc.

b) H zone.

c) M line.

d) A band. 2 / 3

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e) I band. - ANSWER>>c) M line

21) Calcium ions are released from the sarcoplasmic reticulum into the cytosol

• at the beginning of a contraction.
• in response to acetylcholine binding to Ca2+ release channels.
• by active transport using Ca2+ pumps in the SR membrane.
• after the contraction ends.

e) All of these answers are correct. - ANSWER>>a) at the beginning of a contraction

22) What energizes the myosin head?

• the actin filaments
• calcium ions
• potassium ions

d) ATP hydrolysis reaction

e) ADP synthesis - ANSWER>>d) ATP hydrolysis reaction

23) Skeletal muscle contraction will continue to occur as long as the following chemicals are available in the cytosol of the muscle fiber.

a) ATP and acetylcholine (ACh)

• calcium ions and ATP
• / 3