Biochemistry Exam 2 - Lectures 19 and 20

Match the structure to the proper name

• Uracil

• 
• PRPP

• 
• Cytosine

• 
• Thymine

• 

Salvage and de novo synthesis pathways require PRPP to make nucleoside 5 monophosphates. Which of the following statements is false in regards to the reaction needed to synthesize PRPP

• Ribose - 5 - phosphate gets phosphorylated to form PRPP

• ATP is hydrolyzed to AMP to form PRPP

• The PRPP must have the pyrophosphoryl group in the alpha position to be considered active

• PRPP reacts with ATP to form ribose 5 phosphate

Reorder the following steps within the pathway for pyrimidine biosynthesis

• Orotate combines with PRPP to form OMP

• Formation of Carbamoyl-Aspartate from Carbamoylation

• CPSII forms Carbamoyl P

• OMP is decarboxylated to form UMP (Uridine mono phosphate)

• Carbamoyl aspartate loses H2O to form dihydroorotate which is reduced to form orotate

Which of the following molecules are NOT directly involved in pyrinidine synthesis?

• Aspartate

• Glutamine

• NAD+

• NADP+

(a)   is most responsible for the cyclization of carbamoyl aspertate into dihydroorotate

• Removal of a water
• NAD+ to NADH
• Decarboxylation

​ (a)   is involved in the creation of one of the first molecules needed for pyrimidine synthesis to take place.

• CPSII
• CPSI

This molecules is formed directly from UTP, and the enzyme that catalyzes the reaction to form it shows cooperativity in v verses (UTP) plots.

• CTP

• ATP

• TTP

• UTP

The reaction:

UTP + Gln + ATP ↔ CTP + Glu + ADP + Pi

Is catalyzed by which enzyme?

• CTP Synthase

• ATP Synthase

• UTP Synthase

• TTP Synthase

CTP Synthase is activated by ​ (a)   , which is a ​ (b)   , thereby acting to balance the amounts of puring and pyrimidine nucleotides in the body.

• GTP
• Purine
• ATP
• Pyrimidine

Match the abbreviations to the full names

• Cytidine Tri phosphate

• UMP

• Uridine Tri Phosphate

• DTMP

• deoxyuritidine monophosphate

• dUMP

• Deoxythymine monomohsphate

• CTP

• Uridine MonoPhosphate

• UTP