UWORLD MICRO and Biochem

Question 1

Pt with target cells and a microcytic anemia that doesn’t respond to iron. Increase HbF. Mech of defect?

Answer 1

Beta-thalessemia minor. From defect in mRNA splicing of mRNA.

Question 2

Pt with abdominal pain and nausea confusion. Incidents usually occur after drinking alcohol. Urine turns dark upon standing. High dose glucose improves the condition - why?

Answer 2

Acute intermittant porphyria (urine turns port wine colored). Glucose inhibits ALA synthase.

Question 3

Pt inoculated with diphtheria but does not get sick. why?

Answer 3

Has IgG that bind and neutralize toxins

Question 4

Pt with high fever, cough with consolidation and diarrhea. Electrolyte imbalance?

Answer 4

Legionella - Hyponatremia.

Question 5

Pancreatic cells - what substrate makes them release insulin?

Answer 5

ATP (not glucose)

Question 6

Normal Newborns need what vitamins?

Answer 6

D and K

Question 7

Lac operon - repressor binds to?

What binds to promotor?

Answer 7

operator

RNA polymerase

Question 8

After glucose is added, lac operon switched off - mech?

Answer 8

Glucose inactivates AC - lowers cAMP. Need cAMP for lac operon to run

Question 9

Sequence of bases upstream of AUG codon - purpose?

Answer 9

initiator to translation

Question 10

HSV initial infection vs recurrance?

Answer 10

ulcers all over mouth vs only a small area of one side

Question 11

Collagen synthsis - last thing that happens inside cell and first thing that happens outside cell?

Answer 11

inside) assembly of pro-a-chains into triple helix

outside) N- and C-terminal propeptide removal

Question 12

Glycosylase vs endonuclease?

Answer 12

take out base vs take out sugar

Question 13

6 year old with vision problems and mental retardation dies of stroke.

Vitamin that should have been given?

Answer 13

Homocysteinuria. B6

Question 14

Ras/Raf - activated by?

Answer 14

GTP - G-proteins.

Question 15

Pt with S. epidermis endocarditis. Tx?

Answer 15

Vancomycin