Is there a difference between 3- phosphoglycerate and 3-phospho glyeric acid

Is there a difference between 3- phosphoglycerate and 3-phospho glyeric acid. As the word is used interchanbly in ncert. And (ate) means ester and acid is carboxylic acid.

3- phosphoglycerate or 3-phosphoglyceric acid is a biochemically significant 3-carbon molecule that is a metabolic intermediate in both glycolysis and the Calvin cycle. In the Calvin cycle, 3-phosphoglycerate is the product of the spontaneous split of an unstable 6-carbon intermediate formed by CO2 fixation.

Both these compounds have the same molecular formula but different structural formulae. They are interconvertible depending on the state of the reaction.

3-phosphoglyceric acid is a stable species. It has OH group attached to the phosphate. When this compound is about to enter a metabolic reaction, it loses its H ions and gets converted into 3-phosphoglycerate. This compound is unstable and immediately gets stabilized by accepting H ions and gets converted into 3-phosphoglyceric acid.
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