Which of the Following Statements Is TRUE Regarding Skeletal-Muscle Contraction

question 9

Multiple Choice

Which of the following statements is TRUE regarding skeletal-muscle contraction?

• A) Only one cross-bridge cycle can occur when the [Ca²⁺] is elevated in the cytosol; in order to undergo a second cycle, [Ca²⁺] must be sequestered in the sarcoplasmic reticulum and released again.
• B) ATP hydrolysis products must be removed from myosin before it can bind to actin.
• C) Binding of myosin to actin takes place when [Ca²⁺] increases in the cytosol.
• D) A single twitch in skeletal muscle lasts the same length of time as the action potential that causes it.
• E) The powerstroke of the cross-bridge cycle occurs simultaneously with ATP being hydrolyzed into ADP and P_i.

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Definitions:

Perfect Competitor

An entity in a highly competitive market where firms sell homogeneous products, have no control over market price, and where there is free entry and exit of firms.

Elastic Demand Curve

Represents a situation where the quantity demanded of a good or service significantly changes in response to a change in price.

Demand Curve

A graph showing the relationship between the price of a good and the quantity of that good that consumers are willing to purchase at various prices.

Monopolistic Competitor

A market structure where many firms sell products that are similar but not identical, thereby having some control over their prices.