Two different mutations are identified in a haploid strain of yeast. The first prevents the synthesis of adenine by a nonsense mutation of the ade-1 gene. In this mutation, a base-pair substitution changes a tryptophan codon (UGG) to a stop codon (UGA). The second affects one of several duplicate tRNA genes. This base-pair substitution mutation changes the anticodon sequence of a tRNATrp from 3'-ACC - 5' to 3'-ACU - 5'

1. Do you consider the second mutation to be a forward mutation or a reversion?
Do you consider the second mutation to be a forward mutation or a reversion?

a. second-site reversion (suppressor)
b. forward mutation
c. true reversion
d. intragenic reversion

2. Assuming there are no other mutations in the genome, will this double-mutant yeast strain be able to grow on minimal medium?

a. yes
b. no

Which of the following claims does the author support the least

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.

The energy available as a result of the motion of a body is called energy. -potential -gravitational -kinetic -chemical