Biochem TA Session 2

What kind of base structure is this?

• purine

• pyrimidine

Which base is this?

• adenine

• guanine

• cytosine

• thymine

• uracil

Which base is this?

• adenine

• guanine

• cytosine

• thymine

• uracil

Which enzyme is involved in the committed step of pyrimidine synthesis?

• carbamoyl phosphate synthetase II

• aspartate transcarbamoylase

• UMP synthase

• CTP synthestase

What molecule is this?

• orotidine triphosphate

• uridine triphosphate

• carbamoyl aspartate

• 5-phosphoribosyl 1-pyrophosphate

Which of the following inhibits production of carbamoyl aspartate?

• PRPP

• ATP

• CTP

• CMP

What kind of enzyme is responsible for phosphorylation of nucleosides in the purine synthesis pathway?

• phosphatase

• kinase

• synthetase

• lyase

(T/F) Excess CTP inhibits CTP synthetase through a negative feedback loop.

• true

• false

In which of the following pathways is PRPP involved? Select all that apply.

• salvage pathway

• purine synthesis

• de novo pathway

• purine degradation

What are the TWO pathways that diverge during purine synthesis?

• GMP

• IMP

• AMP

• UMP