Molecular Diagnosis MCQ - Practice Questions with Answers

Molecular Probes: 

• Molecular probes are small DNA or RNA fragments.
• They are used to detect complementary sequences in nucleic acid samples.
• There are antibodies probes as well that are used to detect the proteins in the samples.
• The probes are labelled with radioisotopes such as 32P.
• Molecular probes are available for many genetic disorders like Duchenne muscular dystrophy, cystic fibrosis, Tay-Sachs disease, etc.

Blotting:

• The analytical techniques used for identification of a specific DNA, an RNA or a protein from thousands of each is called the blotting technique.
• Southern blotting is used for detection of DNA.
• Northern blotting is used for detection of RNA
• Western blotting is used for detection of proteins

(These techniques have been explained in the video lecture of this concept)

PCR:

• Presence of a pathogen (bacteria, viruses, etc.) is normally suspected only when the pathogen has produced a disease symptom. 
• By this time the concentration of pathogens is already very high in the body. 
• However, very low concentration of a bacteria or virus (at a time when the symptoms of the disease are not yet visible) can be detected by amplification of their nucleic acid by PCR. 
• PCR is now routinely used to detect HIV in suspected AIDS patients. 
• It is being used to detect mutations in genes in suspected cancer patients too. 
• It is a powerful technique to identify many other genetic disorders.

ELISA:

• ELISA is based on the principle of antigen-antibody interaction.
• Infection by a pathogen can be detected by the presence of antigens (proteins, glycoproteins, etc.) or by detecting the antibodies synthesised against the pathogen.