Micro Bio Exam 3 Homeworks

What is the advantage of cDNA over genomic DNA?

cDNA lacks introns because it is made from processed mRNA. It contains exons and can be expressed in bacteria. cDNA is synthesized from mRNA through reverse transcription, allowing researchers to analyze gene expression levels without the interference of non-coding sequences.

What are three applications of biotechnology?

Microorganisms produce useful products; animal cells produce vaccines; genetic engineering produces disease-resistant crops.

What do blue and white colonies mean on ampicillin + X-gal agar?

White + resistant: recombinant plasmid with inserted DNA.

Blue + resistant: plasmid present, but lacZ intact.

Ampicillin-sensitive: no growth.

What is a vector, and how is it different from PCR and a Southern blot?

• Vector: Carries DNA into another cell.

• PCR: Makes copies of DNA.

• Southern blot: Detects specific DNA sequences.