Use of double mutants has been invaluable in studying developmental pathways. In C. elegans, sex is determined by the ratio of sets of autosomes to X chromosomes. A diploid male has one X, and diploid hermaphrodites have two X's
The loss-of-function gene her-1 produces XO worms that are hermaphrodites, but XX worms are unaffected. Mutation of a second gene, tra, causes the XX to develop as male. Given this information, what would be the phenotype of a tra, her-1 double mutant? A) a male nematode
B) a female nematode
C) a hermaphrodite
D) an intersex variant
E) lethality
A
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Substances are often packaged into small ________ for transport, either through the membrane or throughout the interior of the cell.
A. vesicles B. corpuscles C. organelles D. vacuoles
Answer the question using the accompanying figure. All of the orbitals shown in the neon atom are completely filled
with electrons. How many electrons does this neon atom have?
a. 5 b. 6 c. 8 d. 10 e. 16
When dissolved in water, a(n) _____ donates H+; a(n) _____accepts H+
a. acid; base c. buffer; solute b. base; acid d. base; buffer
A plant physiologist treats a leaf with abscisic acid and observes that the stomata close. What happened inside the guard cells during the experiment?
A. Abscisic acid influences the movement of sodium ions out of the guard cells. B. Abscisic acid binds with auxins and induces water molecules to exit the guard cells. C. Abscisic acid binds carbon dioxide and causes carbonate crystals to block the stomatal opening. D. Abscisic acid influences the movement of potassium ions out of the guard cells. E. Abscisic acid causes the guard cells to become more turgid.