First, it's not called "resource packs" but yes "resourcepacks". Second, in a mac it's not called .minecraft. I don't have a mac, so I don't know what the name is. But if you want to install a texture pack, go to "Options" (or settings, depending on the language) and click "Resource Packs". Then, click "Open resource packs folder". It will open the resource packs folder.
Place your resource pack there (zipped or unzipped).
Go back to minecraft, close the Resource Pack chooser and open it again so that it can reload. Then, click the little arrow that appears when you hover the texture pack name and it will be selected. Click "Done" (or "Ok" depending on the language), wait about 10 seconds and your texture pack will be loaded. (I don't know why I made a complete guide of how to install a texture pack, but it can be helpful)