The active site, which is made up of RPB1 and RPB2, from both these subunits, is found at the base of the pincers within a region called the “active center cleft” . The active site works according to the two-metal ion catalytic mechanism for nucleotide addition proposed for all types of polymerase;

#Question id: 5754

#Unit 8. Inheritance Biology

A cell is exposed to EMS (a mutagen that causes guanine to mispair with thymine) and allowed to undergo a few rounds of DNA replication.  The mutational event caused by this mutagen will be

#Question id: 5755

#Unit 8. Inheritance Biology

A researcher studying bacterial toxin predicts that a lysine within the toxin is important for binding it’s target cell.  She used site-directed mutagenesis to change a codon for lysine (AAA) to one for asparagine (AAU).  However, the mutant toxin still binds to its target cell just as well as the wild-type toxin bound and appears to have no other changes. This type of mutation is probably

#Question id: 5756

#Unit 8. Inheritance Biology

Type of mutation caused by an addition or deletion of a base in a polypeptide-encoding part of a gene

#Question id: 5757

#Unit 8. Inheritance Biology

A new E. coli mutant was tested for auxotrophy. The mutant grows on:

minimal medium (M) + arginine (A) + proline (P)

M + P + histidine (H)

M + A + H + P

but not on M or on M + A + H. The mutant requires

#Question id: 5758

#Unit 8. Inheritance Biology

#Question id: 5760

#Unit 8. Inheritance Biology

The fluctuation test of Luria and Delbruck (studying resistance to bacteriophge T1 infection) established that