Explanation: The lambda P L is a very strong promoter and is one of the promoters responsible for transcription of the lambda DNA molecule.

Explanation: Lambda is a very strong promoter recognized by RNA polymerase which is subverted by lambda into transcribing phage DNA.

Explanation: The lambda promoter is repressed by cI gene. Expression vectors that carry the lambda P L promoter are used with mutant E.coli strain.

Explanation: Expression vectors that carry the lambda P L promoter are used with a mutant E.coli host that synthesizes a temperature-sensitive form of the cI protein.

Explanation: At a low temperature that is less than 30 degrees, the mutant cI protein is able to repress the lambda pL promoter.

Explanation: At a low temperature that is less than 30 degrees, the mutant cI protein is able to repress the lambda pL promoter, but at higher temperatures, the protein is inactivated.

Explanation: The T7 promoter is specific for the RNA polymerase coded by the T7 bacteriophage. The phage RNA polymerase is much more active.

Explanation: The phage RNA polymerase is much more active than the E.coli promoter which means that the gene inserted downstream of the promoter is expressed at a high level.

Explanation: A lysogen contains an inserted copy of the phage DNA in its genome. The phage DNA has been altered by placing a lac promoter.

Explanation: Addition of IPTG to the growth medium switches on the synthesis of the T7 RNA polymerase, which in turn leads to gene activation.

Explanation: An efficient expression vector, in addition to a strong and regulatable promoter also contains a cassette containing terminator and binding site.

Explanation: Insertion of the foreign gene into the restriction site fuses two reading frames that start with the E.coli segment and progress without a break.

Explanation: The product of gene expression is a fusion protein, consisting of short peptide coded by the E.Coli reading frame fused to foreign protein.

Explanation: The product of gene expression is a fusion protein, consisting of short peptide coded by the E.Coli reading frame fused to amino terminus.

Explanation: Efficient translation of mRNA produced from cloned gene depends on ribosomal binding site and starting nucleotide sequence.