Recombinant DNA is artificially created DNA by combining genetic material from multiple sources using molecular cloning techniques. Gene therapy aims to cure inherited diseases by providing a correct copy of a defective gene. Vectors, such as plasmids or virus chromosomes, are used to transfer genes into host cells where they can replicate. Restriction enzymes cut DNA at specific sites for molecular cloning. PCR amplifies a DNA sequence to produce thousands of copies.

1. • Define: recombinant DNA
• What is gene therapy?
• What is the function of a vector in genetic engineering techniques?
• Define “reverse transcription”
• What exactly is cDNA (not DNA - c stands for complementary)?
• What is the difference between introns and exons in the DNA (their function)?
• What is the function of a restriction enzyme?
• Give 2 examples of vectors used in biotechnology
• What exactly is a DNA library?
• What the function of Polymerase Chain Reaction (PCR)?
Solution
1. DNA that has been created artificially are Recombinat DNA. this is done by using molecular
cloning where we bring bring together genetic material from multiple sources.the created
sequences that would not be found in the genome.
2. Gene Therapy is the name originally given to methods that aim to cure an inherited disease by
providing the patient with a correct copy of the defective gene. Gene therapy has now been
extended to include attempts to cure any disease by introduction of a cloned gene into the
patient..
3. DNA molecules, capable of entering a host cell and, once inside, replicating to produce
multiple copies of itself.Two naturally occuring types of DNA molecules satisfy these
requirements
1.Plasmids
2.Virus Chromosomes
4. the DNA which is synthesized from an RNA template via reverse transcription.
5. Introns are nucleotide sequences seen within the genes which are removed through RNA
splicing for to form mature RNA molecule and exons can be termed as DNA bases which are
translated into mRNA.
6. restriction enzyme are the enzymes that cuts the DNA at specific site as restriction sites used
mainly in molecular cloning.
7. The cloning vectors
pBRR322 : the copy number is 15 to 20
pUC vectors: the copy number is 500 to 700
8. DNA library- Libraries can conveniently be divided into two categories: genomic libraries,

2. which are made from the total genomic DNA of an organism, and cDNA libraries, which are
made from DNA copies of its RNA sequences.
9.PCR used to amplify a single copy or a few copies of a piece of DNA into thousands to
millions of copies of a particular DNA sequence.