Molecular Diagnostics

Question 1

Direct ELISA

Answer 1

Ag-coated plate
Ab mixture

OR vise versa

Question 2

Indirect ELISA

Answer 2

measures ANTIBODY in sample
Ag-coated well
Ab mixture
2Ab-enzyme added -> fluorescence

HIV - diagnose if Abs are present, confirm w/ Western blot

Question 3

Sandwich ELISA

Answer 3

measure ANTIGEN in sample
Ab-coated well
Ag mixture
2Ab-enzyme added -> fluorescence

MI detection - troponin as Ag
Pregnancy - hCG as Ag

Question 4

Modified Insulin

Answer 4

Normal insulin - Pro (P28), Lys (P29) on C-term of Bchain

Lispro - reversed Pro, Lys
Insulin Aspart - Pro replaced by Asp

faster acting forms of insulin
-> pair w/ normal insulin for longer range of glycocemic control

Question 5

techniques to detect infectious agents

Answer 5

hybridization

PCR, qPCR

Question 6

techniques to detect inherited disorders

Answer 6

hybridization

PCR, qPCR

Question 7

techniques to detect variations in DNA sequence

Answer 7

restriction fragment length polymorphisms (RFLPs)

variable # of tandem repeats (VNTRs)

Question 8

Sickle cell detection

Answer 8

• characterized by 2 restriction sites vs. 3 in healthy cells
  –> use RFLPs
  normal B-globulin allele has 3 restriction sites

expose sample to endonuclease 
compare number of cuts 
Southern blotting (DNA)

Question 9

Huntington’s detection

Answer 9

• characterized by CAG repeats
  –> use VNTRs
  use probe to detect how many of these repeats are present, compare to healthy

Question 10

blotting techniques

Answer 10

Southern - DNA probe, DNA target -> gene abnormalities/disease

Northern - DNA probe, RNA target -> gene expression

Western - ptn/Ab target

Eastern - post-translational modification target