Question

1. what is the difference between a circulating and local hormone?
2. use the following table to contrast circulating hormone types

a.
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$$\begin{tabular}{|l|l|l|} \\hline & water-soluble & lipid soluble \\\\ \\hline polar or nonpolar & & \\\\ \\hline do they require a carrier molecule in the blood? & & \\\\ \\hline can they enter the target cell? & & \\\\ \\hline do they require g-protein signaling? & & \\\\ \\hline \\end{tabular}$$

Explanation:

Analyze chemical polarity

Using the Hormone Classification and Endocrine System knowledge points

• Water-soluble hormones are polar molecules that dissolve easily in aqueous environments.
• Lipid-soluble hormones are nonpolar molecules that are hydrophobic.

Determine blood transport requirements

Using the Hormone Classification and Endocrine System knowledge points

• Water-soluble hormones travel freely in the blood plasma without carrier proteins.
• Lipid-soluble hormones require transport/carrier proteins to remain dissolved in the bloodstream.

Evaluate target cell entry

Using the Hormone Classification and Endocrine System knowledge points

• Water-soluble hormones cannot cross the phospholipid bilayer of the plasma membrane.
• Lipid-soluble hormones easily diffuse directly through the plasma membrane into the cell.

Identify signaling mechanism requirements

Using the Hormone Classification and Endocrine System knowledge points

• Water-soluble hormones bind to extracellular receptors, often activating G-protein signaling pathways.
• Lipid-soluble hormones bind to intracellular receptors, acting directly as transcription factors without G-proteins.

Answer:

	Water-Soluble	Lipid-Soluble
Do they require a carrier molecule in the blood?	No	Yes
Can they enter the target cell?	No	Yes
Do they require G-protein signaling?	Yes (typically)	No