Random LOs

Question 1

What is the feedback mechanisms in pyrimidine synthesis?

Answer 1

UDP/UTP inhibits Carbomoyl phosphate synthetase II
ATP/PRPP stimulate Carbomoyl phosphate synthetase II
dATP inhibits Ribonucleotide Reductase

Question 2

What are the steps in treating a tissue sample?

Answer 2

1.) Fixation with formalin 2.) Treatment with paraffin wax 3.) Process it by dissolving paraffin rehydrating staining and then dehydrating, fix it to a slide

Question 3

What type of tissues do not stain normally?

Answer 3

Adipose tissue and tissues with high levels of glycogen

Question 4

What stain can be used to show fats and glycogen?

Answer 4

Periodic Acid Schiff (enzyme histochemistry stain)

Question 5

What are two common tissue sample artifacts?

Answer 5

Tissue freezing mimicking lymphovascular invasion because retraction of the neoplastic cells from the surrounding stroma; Also Orphan Annie nuclei, neoplastic cells look to be cleared out of chromatin when it is pushed to the side of the cellular membrane.

Question 6

What undoes the phosphorylation done by PKA?

Answer 6

Phosphoprotein phosphatase