You need that run Profile Sync to see your groups in SharePoint
When a group is created in AD you can choose that as "Distribution list" or as "Security group"
SharePoint can resolve only the Security group not the DL. Saying that you can give permission to users for SharePoint site by adding the particular security group in SharePoint need not add all the users one after other individually
Ps:
Distribution list - you can send mails from Outlook
Security Group- you can send mail from Outlook ,can be used in SharePoint