Why does cholesterol have a stereocenter at carbon 2?

[alingy1]

Can anyone explain why cholesterol has a stereocenter at carbon 2?
http://www.chemguide.co.uk/basicorg/isomerism/cholesterol2.gif
The ring attached right next with the OH group is symetrical.

 

[Saitama]

Can anyone explain why cholesterol has a stereocenter at carbon 2?
http://www.chemguide.co.uk/basicorg/isomerism/cholesterol2.gif
The ring attached right next with the OH group is symetrical.

Why not? For the carbon to be a stereocentre, the four groups attached to it must be different and the condition is satisfied here.

 

[Borek]

The ring is not symmetrical - carbons next to the carbon 2 are not equivalent (one is sp3, the other is sp2).

 

[alingy1]

Could you draw me what the other stereoisomer would look like? I have a huge inability to visualize it. I ended up breaking a part of my model sticks.

 

[Borek]

Assuming the bond going down from the carbon 2 lies on the screen surface, methyl group can either go below the screen, or in front of the screen. As the carbon is sp3 two other bonds have to go the other side.