AOA,

It is necessary to say bismillah arrahman arraheem in every rakat of prayer before surah fatiha and after surah fatiha when we read verses from quran in first two rakats of prayer?
In congregational prayer if I join in 3rd rakat and after 3rd and 4th rakat with imam. I have to read verses from quran after surah fatiha in the rakats that i missed or not?