You Are a Scientist Performing an Experiment on Some Isolated

question 92

Multiple Choice

You are a scientist performing an experiment on some isolated skeletal muscle fibers. You observe that when you observe the muscle fibers under a microscope and apply a small amount of calcium, the fibers contract, but then after a short time they relax back to their original length. Which of the following is (are) possible explanation(s) for this observation?

• A) The applied Ca²⁺ activates the muscle, but following the refractory period the Ca²⁺ loses its effect and the muscle relaxes.
• B) The applied Ca²⁺ activates the muscle, but the muscle soon dephosphorylates its myosin and relaxes.
• C) The applied Ca²⁺ at first activates the muscle, but then is pumped into the sarcoplasmic reticulum and is stored.
• D) All of the choices are possible.

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Definitions:

Acoustically

Pertaining to the properties of sound or the science of sound, including its production, transmission, and effects.

Short-Term Memory

A capacity for holding a small amount of information in conscious awareness for a brief period of time.

Sensory Memory

The immediate, very brief recording of sensory information in the memory system.

Memory Span

The amount of information or number of items one can hold in short-term memory at one time.