#Question id: 14808
#Unit 4. Cell Communication and Cell Signaling
#Question id: 8296
#Unit 9. Diversity of Life Forms
Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species.
According to the phylogenetic tree in the figure above, G. intestinalis constitutes a ________ group.
#Question id: 28393
#Unit 5. Developmental Biology
The mechanism for this “bottom-up” specification of the frog embryo resides in a set of mRNAs that are tethered to the vegetal cortex. This includes the mRNA such as___
#Question id: 3827
#Unit 3. Fundamental Processes
It takes about the same amount of time for eukaryotic chromosomes to be replicated in vivo as it does for E. coli. Why is this true?
#Question id: 24285
#Unit 4. Cell Communication and Cell Signaling
Adherens junctions: