chem---optical activity

The structure of dopamine cannot be found by the above link, but can be found in the following webpage :
http://www.biopsychiatry.com/dopamine/dopamine.jpg


圖片參考：http://www.biopsychiatry.com/dopamine/dopamine.jpg

Dopamine is optically inactive, because there is no chiral carbon atom (sp3 carbon atom with 4 different groups/atoms attached to it) in its molecule.

no.
to determine whether a compound is ooptically active, both of the following criteria should be fulfilled

1)the existence of sp3 hybridised carbon:
it is possible only for sp3 to give a chiral centre.
2)the existence of chiral centre:
if the four substituent group of a sp3 carbon is different from each other, it is a chiral centre

there are only two sp3 carbon on the long carbon chain binded with amino group (-NH2)
however, both of them are respectively binded with two same H- group.

only criterion (1) is fulfilled. the compound is not optically active.