Thyroxine Is a Peptide Hormone, but Its Mechanism Is Different

question 28

Multiple Choice

Thyroxine is a peptide hormone, but its mechanism is different from other peptide hormones. Which of the following statements is true concerning this difference?

• A) It is very specific in the cell type it targets.
• B) It is a stimulant of cellular metabolism and targets all cells.
• C) It does not require a second messenger to effect a response.
• D) It causes positive feedback.

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Definitions:

Placebo

A substance or treatment with no therapeutic effect, often used in the control group of experiments to test the efficacy of treatments.

Field Experiment

An experimental research study conducted in a real-world setting where the researcher manipulates one or more variables to determine their effect.

Experiment

A scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact, involving the manipulation of variables under controlled conditions.

Unethical

Actions or behaviors that are deemed wrong or unacceptable according to moral principles or societal standards.