‘Family planning’ is a broad term that includes any measures taken to responsibly prevent pregnancy (birth control, contraception, planning, abortions, permanent infertility procedures, etc.). Birth control, however, is specifically designed to intervene in a woman’s natural hormones to drastically reduce the possibility of pregnancy (much like contraception)
Purines: Heterocyclic rings are synthesized one atom at a time, first atom attached to ribose phosphate (source is PRPP) and then all the other atoms are added .
Pyrimidines: Common intermediate, orotate, synthesized first, then orotate is attached to ribose phosphate (source is PRPP or 5-Phosphoribosyl-1-pyrophosphate).