1. DNA libraries contain cloned DNA fragments from an organism that can be used to isolate specific genes of interest. There are two main types: genomic libraries containing all DNA, and cDNA libraries containing expressed mRNA. 2. Bacterial transformation is a process where bacteria take up foreign DNA through horizontal gene transfer. It is used to clone and replicate plasmids in bacteria. 3. Chromosomal jumping and walking are techniques used in genome mapping and sequencing. Jumping allows bypassing repetitive sequences, while walking maps contiguous overlapping fragments to identify adjacent sequences.