Simulation · Biology · Class 12
Catch it before the symptoms
From the lesson Molecular diagnosis in Biotechnology and its Applications. Change the values and watch what happens.
Catch it before the symptomsBiology · Class 12
The idea behind it
NCERT §10.2.3
- Effective treatment needs early diagnosis and an understanding of the disease's pathophysiology. Conventional methods such as serum and urine analysis cannot detect disease early.
- Early diagnosis is possible with three techniques: recombinant DNA technology, PCR (Polymerase Chain Reaction) and ELISA (Enzyme Linked Immuno-sorbent Assay).
- A pathogen is usually suspected only after it causes symptoms, by which time its concentration in the body is already very high.
- PCR amplifies the nucleic acid of a bacterium or virus, so it can be detected at a very low concentration, before symptoms appear.
- PCR is now a routine test for HIV when AIDS is suspected, and it finds gene mutations when cancer is suspected. It also identifies many other genetic disorders.
- A probe is single-stranded DNA or RNA carrying a radioactive tag. The probe is left to pair (hybridise) with complementary DNA in a clone of cells and is then located by autoradiography.
- A clone carrying a mutated gene does not show on the photographic film, because the probe is not complementary to the mutated gene.
- ELISA works on antigen-antibody interaction. Infection is detected either from the pathogen's antigens (proteins, glycoproteins and so on) or from the antibodies made against the pathogen.