Question

What is the primary mechanism of absorption for fluoride ions when ingested?

A) Conversion to hydrogen fluoride by stomach acid followed by diffusion across cell membranes.
B) Active ion transport mechanisms across cell membranes.
C) Absorption occurs via passive diffusion without chemical conversion.
D) Multiple mechanisms contribute equally to fluoride ion absorption.

Answer 1

Fluoride ions are primarily absorbed through passive diffusion after being converted to hydrogen fluoride by stomach acid.

Step-by-step explanation:

The primary mechanism of absorption for fluoride ions when ingested is through passive diffusion following the conversion to hydrogen fluoride by stomach acid. Initially, the fluoride ion (F-) can react with water in a neutralization reaction to form hydrogen fluoride (HF).

This reaction is described by the equation F- (aq) + H2O (l) ⇒ HF (aq) + OH- (aq). Hydrogen fluoride (HF) can then diffuse across cell membranes, as the stomach's acidic environment allows F- to convert to HF, which is more easily absorbed because it is more permeable to the cell membrane due to its uncharged state.