BIO 253 Midterm Questions and Answers
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The muscle cell doesnt stockpile large quantities of ATP. How does the muscle ensure enough
ATP for intense exercise? At rest, some ATP transfers a phosphate to creatine and creates
phosphocreatine. This can be used to resynthesizes ATP during intense exercise for the
contraction to continue.
During repeated skeletal muscle contraction, what happens to calcium within a single motor unit
that may lead to fatigue? What is it's overall effect? A reduction in calcium ion release
due to depletion of Ca2+ ions from intracellular stores: The SR inhibits excitation-contraction
coupling.
If EMG electrodes were placed on the flexor digitorum superficialis (one of the muscles involved
in maintaining grip) while applying sustained max force, what would the EMG trace look like as
you encounter fatigue for both the raw data and the RMS data? Raw data would be
spikey, and then get smaller.
RMS data would be a nice curve that starts as a plateau and then slopes down
Why is high intensity anaerobic exercise limited in duration? Lactic acid breaks down
and contributes to fatigue by interfering with contractile processes and by changing the pH of the
, BIO 253 Midterm Questions and Answers
Verified by Experts
muscle cell. The tolerance for decreasing pH in muscle cells is limited. As pH decreases,
enzymes denature and anaerobic respiration becomes inefficient.
What could be some sources of error (that do not include improper use of the equipment or not
following procedure correctly) in this whole lab that could have affected your data? (LAB one)
Interference due to movement or sounds
Placement error (human error)
Define isometric contraction and describe an example An isometric contraction is a
muscle contraction that sees the muscle remain at the same length in which there is no movement
of the joint.
Holding a wallsit is an example
When the current reached the following stages, what proportion of fibers in the muscle were
contracting?
- At threshold
- At max
- Above the maz - At threshold only a few of the fibers are being recruited.
- 100% of the fibers are being recruited and contracting
Verified by Experts
The muscle cell doesnt stockpile large quantities of ATP. How does the muscle ensure enough
ATP for intense exercise? At rest, some ATP transfers a phosphate to creatine and creates
phosphocreatine. This can be used to resynthesizes ATP during intense exercise for the
contraction to continue.
During repeated skeletal muscle contraction, what happens to calcium within a single motor unit
that may lead to fatigue? What is it's overall effect? A reduction in calcium ion release
due to depletion of Ca2+ ions from intracellular stores: The SR inhibits excitation-contraction
coupling.
If EMG electrodes were placed on the flexor digitorum superficialis (one of the muscles involved
in maintaining grip) while applying sustained max force, what would the EMG trace look like as
you encounter fatigue for both the raw data and the RMS data? Raw data would be
spikey, and then get smaller.
RMS data would be a nice curve that starts as a plateau and then slopes down
Why is high intensity anaerobic exercise limited in duration? Lactic acid breaks down
and contributes to fatigue by interfering with contractile processes and by changing the pH of the
, BIO 253 Midterm Questions and Answers
Verified by Experts
muscle cell. The tolerance for decreasing pH in muscle cells is limited. As pH decreases,
enzymes denature and anaerobic respiration becomes inefficient.
What could be some sources of error (that do not include improper use of the equipment or not
following procedure correctly) in this whole lab that could have affected your data? (LAB one)
Interference due to movement or sounds
Placement error (human error)
Define isometric contraction and describe an example An isometric contraction is a
muscle contraction that sees the muscle remain at the same length in which there is no movement
of the joint.
Holding a wallsit is an example
When the current reached the following stages, what proportion of fibers in the muscle were
contracting?
- At threshold
- At max
- Above the maz - At threshold only a few of the fibers are being recruited.
- 100% of the fibers are being recruited and contracting
