USMLE STEP 1 BIOCHEMISTRY Questions and Answers with Complete Solutions 2024

USMLE STEP 1 BIOCHEMISTRY Questions and Answers with Complete Solutions 2024 Achondroplasia involves what defect? - ANSCell-signlaling defect of fibroblast growth factor (FGF) receptor 3 Marfan's syndrome involves a mutation in what? - ANSFibrillin gene Nucleoside + phosphate= ? - ANSNucleotide Adenine and Guanine are in what type of nucleic acid? - ANSPurines Cytosine, Uracil and Thyamine arein what kind of nucleic acid? - ANSPyrimidines Xanthine, hypoxanthine and uric acid are all what type of base? - ANSPurine How many hydrogen bonds are found between Guanine and Cytosine? - ANS3 Chargaff's ruledictates that the percent of adenine in a DNA molecule is = to the % of _____ in a DNA molecule. - ANSthyamine What is the rate limiting step in Purine de novo synthesis? - ANSPRPP step via glutamin PRPP amidotranferase PRPP amidotransferase inhibited by what downstream products in purine synthesis? - ANSIMP, GMP, AMP and puring analogs Allopurinola and 6- mercaptopurine What are the required cofactors for purine de novo synthesis? - ANSTHF, glutamine, glycine, aspartate, CO2 Name two crucial enzymes involved in purine salvage pathways - ANShypoxanthine Phosoribosyltransferaase