why antibiotics are used in preparation of media for karyotyping using giemsa banding?

Answer 1

Antibiotics (mostly penicllins) are used as 'Nutrient' in preparation of media for Karyotyping. While preparing chromosomes for analysis cultured cells are placed in a nutrient solution containing amino acids and other nutrients such as antibiotics and a pH indicator, with or without mitogens, and then grown at the desired temperature (usually 37 Celsius) in CO2 atmosphere.