Unformatted text preview: 17. 18. I9. 20'. /: Which of the following statements concerning Hypoxanthine
Phosphoribosylnansferasc (HPR'I‘). is TRUE? ,A< HPRT IS involved in the salvage pathway of pyrimidines.
‘3.) HPRT has binding sites for both hypoxanthine and PPRP/
Partial deﬁciency in HPRT results tn LeschsNyhan Syndrome. »
. All Lesch-Nyhan patients have the same mutation in the HPRT gene.
E. HPRT is involved in the m pathway of purines. ' The synthesis of PRPP (phospho-nbosyl pytophosphate) Is: (99:00 03L (No
Q), Inhibited by ADP ./
B. V Stimulated by GDP g
c. Stimulated by CDP
D Inhibited by or? 29 E... None of the above. All ofthe following smancnts concerning most eukaryotic mRNAs are true
EXCEPT which one? A. Itismadeasalargeprccursor.‘// /
B. Ithasapolyadenylic acid scquenceatthe3' end.
-C. ItisprodueedinlItltenucletmw (EN Itlaeksthe' csp" structureofprolraryotiesnRNA.>< my E. ItissyndtesincdS'-3'. / Each of the following Statements is true about mRNA in most cells EXCEPT which
one? . . A. Itisheterogenousinsize. u/
Itcodesforproteins. / B.
'56; Containssevemlmodiﬁcdbasesﬁ D. It is synthesized on DNA.‘/
‘5. It contains untranslated nucleotides. / 21 In which of the following ways does DNA diﬁ‘er from RNA? Q Item inDNAare linkedby 3'. 5' phosphodiesterbridges while. thebases in RNA are usually linbd by 2', 3’ phosphodiester bridges. DNA contains ribothymidine whereas RNA contains dihydrouraciL In the duplex DNA molecule the number of purine bases equal the number of \/
pyrimidinebaseswhilethisisusuallynottrueforRNA. DNA contains only purine bases while RNA contains only pyrimidine bases.
None of the above. ' g _ W or 152 7 ...
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- Spring '08