Use the development of a floral structure in plants to demonstrate the role of sequential gene expression during development
What will be an ideal response?
Sequential expression of A, B, and C floral identity genes gives rise to four whorls of tissue in a floral shoot. Each whorl produces one floral structure: sepals, petals, stamens, or carpels. Expression of the A gene triggers development of the outer whorl, which produces sepals. Then, the overlapping expression of genes A and B trigger petals to form in the second whorl. Again, the overlapping expression of gene B and C together trigger stamens to form in the third whorl, and then the remaining C gene expression alone triggers carpel development in the inner whorl. It is the sequential and overlapping expression of these three genes that triggers the development of four floral structures.
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Use the following study to answer the following question(s): A researcher applies varying amounts of fertilizer (0, 2, 4, 8, 10 units) to 50 potted tomato plants. All other variables that may affect the outcome (watering, temperature, sunlight, plant size, etc.) are kept the same from pot to pot. At the end of the growing season, the tomatoes grown on each plant are weighed to determine which fertilizer level produced the largest tomato yield.Is the study presented above a controlled experiment?
A. Yes, because many pots were used. B. No, because the experiment was done only once. C. No, because several different amounts of fertilizers were used, not just one amount. D. Yes, because only the amount of fertilizer was changed, everything else was kept the same.
In G2, there are typically high levels of the mitotic cyclin. Why is cdc2 not active during G2 if the mitotic cyclin is present?
A. Cdc2 is also regulated by phosphorylation. B. Cdc2 does not bind to the mitotic cyclin. C. Cdc2 requires ubiquitination to be activated. D. Cdc2 also has to bind to cohesin to be activated.
In prokaryotes, the form of RNA polymerase that can accurately initiate synthesis of RNA is called
A. the holoenzyme. B. the core polymerase. C. RNA polymerase II. D. RNA polymerase III. E. the sigma subunit.
Which of the following is NOT characteristic of a coliform?
A) facultatively aerobic B) gram-negative C) rod shaped D) resistant to chlorination