You grow a culture of bacteria and split it into two culture tubes. One sample of bacteria you treat with calcium and the other is not treated. When you transform both samples with a plasmid, only the samples treated with calcium take up the plasmid. Which of the following best explains your results?
A. DNA is degraded in the absence of calcium.
B. Calcium precipitates DNA, preventing it from being taken up by cells.
C. The bacteria require calcium to grow.
D. The calcium makes the bacterial membrane more porous to DNA.
E. The bacteria use calcium as a source of energy to take up the DNA.
D. The calcium makes the bacterial membrane more porous to DNA.
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The structure labeled "C" in this figure of a replication fork represents ____
a. single-stranded binding protein b. primase c. DNA ligase d. helicase e. DNA polymerase
Abscission of fruits and leaves is controlled by
a. abscisic acid. b. ethylene. c. gibberellin. d. auxin. e. cytokinin
A water-vascular system is characteristic of the
phylum a. Arthropoda. b. Annelida. c. Chordata. d. Mollusca. e. Echinodermata.
Imagine that a very unusual animal species had the ability to make its own aromatic amino acids using a 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase enzyme similar to that of plants. What would happen if this animal foraged in a field of glyphosate-resistant plants?
A. They would also become glyphosate-resistant B. They would no longer need to make their own aromatic amino acids C. No effect D. They would become sick from the glyphosate that was sprayed on the plants