What is the number of stereo structure of glucose?

The open-chain structure of glucose is an aldohexose with the chemical formula $CHO-(CHOH)_4-CH_2OH$.

In this structure, there are $4$ chiral carbon atoms (the four $CHOH$ groups).

Since the molecule is unsymmetrical (the two terminal groups are different, $CHO$ and $CH_2OH$), the total number of stereoisomers is given by the formula $2^n$, where $n$ is the number of chiral centers.

Substituting $n = 4$, we get $2^4 = 16$.

Thus, there are $16$ possible stereo structures for an aldohexose like glucose.

Answer: $16$