Barchu

Question

I was learning the laws of "barchu" (Orach Chayim 57) and did not see anything written regarding the sheliach tzibbur bowing when saying aloud "barchu", nor is anything mentioned about the congregation bowing when ansering "baruch H. hamevorach etc". 1. Is it obligatory to bow for this? Or is it optional? 2. If the tzibbur bows for barchu, is it then considered Poresh min hatzibbur (separating oneself from the community)? Please advise the proper practice. Thank you.