Embryonic induction, the influence of one group of cells on another group of cells, plays a critical role in embryonic development. In 1924, Hans Spemann and Hilde Mangold transplanted a piece of tissue that influences the formation of the notochord and neural tube, from the dorsal lip of an amphibian embryo to the ventral side of another amphibian embryo. If embryonic induction occurred, which of the following observations justifies the claim of embryonic induction?

#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