Answer:
*Thymidine
*THF to DHF
*THF
Step-by-step explanation:
Normal cells die in a nutrient medium containing thymidine and methotrexate, whereas mutant cells defective in thymidylate synthase survive and grow. The mutant cells grow because the medium contains the_____Thymidine______ they are unable to make normal cells, however, continue to synthesize their own and thereby convert their limited supply of to__THF to DHF______ . The methotrexate inhibits , so cannot be regenerated. Without a supply of______THF_____ for the synthesis of nucleotides and amino acids, the cells die.
NOTE:
THF means Tetrahydrofolate
DHF means Dihydrofolate
Thymidine which is also reffered to as deoxythymidine, is described as a deoxynucleoside that is composed of the pyrimidine base thymine that is attached to the sugar deoxyribose. Thymidine is a nucleoside made up of pentose sugar, pyrimidine base tymine and deoxyribose, it is one of the the four nucleoside found in exclusively DNA as well as T-loop of tRNA.
Tetrahydrofolate also known as tetrahydrofolic acid can be described as part of folic acid that function as a coenzyme which aid metabolic reactions that includes nucleic acid and amino acids. It is also reffered to as one-carbon metabolism, and it's oone-carbon mechanism is associated to the histidine, serine of amino acid.