Biochem 2

Question 1

Methylation of DNA

Answer 1

-On A and C, contain C=O

Question 2

Amino Acids necessary for Sugar Production

Answer 2

-Glycine, Glutamate, Aspartate

Question 3

Pyrimidine Synthesis

Answer 3

• Ribose-5P from HMP shunt makes PRPP combines with orotic acid (Carbampyl phosphate in urea cycle) to form UMP -Requires Ribonucleotide reductase
• UMP goes into CMP
• UMP then goes into TMP but reaquires DHFR and Thymitidylate synthase
• DHFR inhibited by MTX and TMP
• TS inhibited by 5-FU

Question 4

Purine Synthesis

Answer 4

PRPP goes into IMP

• Blocked by 6-Mercaptopurine
• IMP goes into GMP and AMP

Question 5

Purine Salvage

Answer 5

• GMP recycled to hypoxanthine which is converted to inosine that can then be recycled to GTP and ATP
• AMP degraded to Inosine by ADA which can then be recycled
• If not recycled, goes to hypoxanthine then xanthine then uric acid

Question 6

ADA

Answer 6

-Loss of ADA prevents recycling of adenosine to inosine. Leads to an accumulation of ATP and negative feedback on Ribonucleotide Reductase and stops production.

Question 7

Lesch-Nyhan

Answer 7

• HGPRT normally recycles to Inosine, lack leads to no recycling and increased loss
• Leads to increased uric acid