If you mean can the 70-200mm be used at 105mm, then yes. But the subject must be at or further than the minimum shooting distance for that zoom lens at 105mm. To shoot closer than that distance to get greater magnification, then it can only be done with a real 105mm f/2.8 macro lens.
As for performance with respect to image quality, prime lenses will almost always be better than a zoom lens at the same focal length.
So it depends on what kind of macros you want to shoot, big subjects like flowers which would allow you to stand far enough away to shoot with a zoom lens or small subjects like ants which require you to be very close to your subjects and what is your requirement or standard for image quality. All these only you can answer .