#Question id: 11127
#Unit 7. System Physiology – Animal
As the receptor potential rises higher above threshold, which of the following best characterizes the new frequency of action potentials?
#Question id: 4725
#Unit 8. Inheritance Biology
Ptosis (droopy eyelid) may be inherited as a dominant human trait. Among 30 people who are heterozygous for the ptosis allele, 10 have ptosis and 20 have normal eyelids. What is the penetrance for ptosis?
#Question id: 3655
#Unit 3. Fundamental Processes
The mismatched base is removed from the daughter strand of DNA by:
#Question id: 10486
#Unit 6. System Physiology – Plant
A patch clamp study shows a guard cell protoplast treated in the dark with the fungal toxin fusicoccin which is a well-characterized,
#Question id: 12958
#Unit 10. Ecological Principles
The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years
Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.
Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
The strong dependence of RR individuals on large quantities of vitamin K probably is responsible for