Which of the following is NOT a valid distinction between a blastocoel, an archenteron, and a coelom?
A. During development these cavities appear in the sequence blastocoel, archenteron, coelom.
B. The blastocoel forms the cavity of the digestive tract, the archenteron forms the chest cavity, and the coelom forms the cavity of the digestive tract.
C. The blastocoel is bounded only by an external germ layer, the archenteron is bounded by inner and outer layers of germ cells, and the coelom is a cavity within the mesoderm.
D. The archenteron has a direct opening to the outside of the embryo whereas the other two cavities do not.
E. None of the other choices are correct.
B. The blastocoel forms the cavity of the digestive tract, the archenteron forms the chest cavity, and the coelom forms the cavity of the digestive tract.
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H. V. Wilson worked with sponges to gain some insight into exactly what was responsible for holding adjacent cells together. He exposed two species of differently pigmented sponges to a chemical that disrupted the cell-cell interaction (cell junctions)
, and the cells of the sponges dissociated. Wilson then mixed the cells of the two species and removed the chemical that caused the cells to dissociate. Wilson found that the sponges reassembled into two separate species. The cells from one species did not interact or form associations with the cells of the other species. How do you explain the results of Wilson's experiments? A) The two species of sponge had different enzymes that functioned in the reassembly process. B) The molecules responsible for cell-cell adhesion (cell junctions) were irreversibly destroyed during the experiment. C) The molecules responsible for cell-cell adhesion (cell junctions) differed between the two species of sponge. D) One cell functioned as the nucleus for each organism, thereby attracting only cells of the same pigment.
Imagine that you have isolated a yeast mutant that contains a constitutively (constantly) active histone deacetylase. What phenotype do you predict for this mutant?
A) The mutant will grow rapidly. B) The mutant will require galactose for growth. C) The mutant will show low levels of gene expression. D) The mutant will show high levels of gene expression.
An evil genius wants to stop all vascular plants from photosynthesizing. He decides to send his minions out to cut off the structures in plants where most photosynthesis takes place. Which structures should his minions remove?
A. roots B. flowers C. leaves D. stems
It is estimated that 4.6% of SNPs and about 17% of all genes can be defined as pleiotropic. Based on this finding, which of the following should a consumer of genetic information keep in mind?
A) A test identifying a gene for a disease might actually be a test for a different disorder instead. B) Any variant that we gain information about might in the future be found to associate with a more stigmatizing condition. C) A physician might be treating the major condition but not notice even more deleterious outcomes. D) The classification of my genetic disorder might be incorrect. E) Sequencing of the candidate gene might find the wrong expected functional significance.