Question

what is the purpose of the phosphate buffered saline (pbs) in the dna extraction protocol?

a. it is used as the main buffer in the pcr reaction.

b. it is used to denature proteins that were released from the cell.

c. it is used to breakdown the cell membrane to release the dna.

d. the swab containing cheek cells is swirled around in this buffer to collect the cells.

clear my choice

Explanation:

• Option a: PBS is not the main buffer in PCR. PCR has its own specific buffers.
• Option b: PBS does not denature proteins. Denaturing agents like heat or certain chemicals are used for that.
• Option c: PBS does not break - down cell membranes. Detergents are used for cell - membrane lysis.
• Option d: In DNA extraction from cheek cells, the swab with cheek cells is swirled in PBS to collect the cells as PBS provides a suitable environment (isotonic) to keep the cells intact during collection.

Answer:

d. The swab containing cheek cells is swirled around in this buffer to collect the cells.