Question

14a. what is blast used for and how is it used to find the identity of a pathogen? b. how does elisa identify a pathogen? c. are elisa tests specific or can they be used to detect many different pathogens? explain.

Explanation:

a. BLAST (Basic Local Alignment Search Tool) is used for comparing nucleotide or protein sequences against a database of known sequences. To find the identity of a pathogen, the sequence of an unknown pathogen is inputted, and BLAST searches for similar sequences in its database. High - scoring matches can indicate the pathogen's identity.
b. ELISA (Enzyme - Linked Immunosorbent Assay) identifies a pathogen by detecting specific antibodies or antigens. Antibodies specific to the pathogen are immobilized on a surface. If the sample contains the pathogen (antigen), it binds to the antibodies. A secondary antibody with an enzyme attached is then added. The enzyme catalyzes a reaction that produces a detectable signal.
c. ELISA tests can be both specific and used to detect multiple pathogens. Some ELISA tests are highly specific for a single pathogen, targeting a unique antigen. However, multiplex ELISAs can be designed to detect multiple different pathogens simultaneously by using a panel of specific antibodies.

Answer:

a. BLAST is used for sequence comparison. To find pathogen identity, input unknown pathogen sequence and search database for matches.
b. ELISA detects specific antibodies/antigens. Antibodies bind pathogen (if present), and a secondary antibody - enzyme complex creates a detectable signal.
c. ELISA can be specific for single pathogen or detect multiple. Specific ones target unique antigen; multiplex ELISAs use antibody panels for multiple pathogens.