The tac promoter, an artificial promoter made from portions of the trp and lacUV5 promoters, has been introduced into a plasmid. It is a hybrid of the lac and trp (tryptophan) promoters, containing the −35 region of one and the −10 region of the other. This promoter directs transcription initiation more efficiently than either the trp or lac promoters. Why? Match the words in the left column to the appropriate blanks in the sentences on the right.

reason is that it uses the -35 region of the trp promoter and -10 region of the lacUV5 promotor, the tac promotor more closely resembles the consensus -35 and -10 sequences than either trp or lac. Tac has 12 out of 12 identiies with the consensus sequences, whereas lac and trp have 9.

Tac promotor is a synthetic, 2hybrid promoter widely used in E.coli for protein production in E.coli using the same induction and repression systems of lac promotor.

Explanation:

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.