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In biofilm-forming bacteria, intracellular signaling molecules serve as messengers to coordinate a shift from ________ to ________ growth.

Given these 16S rRNA sequences, which two bacteria are most closely related? Escherichia coli AUUCGCGAUC Proteus vulgaris AUGCGGGAAC Salmonella enterica AAUCGCGAUC Citrobacter freundii AUUGGCCAUC

Photosynthetic organisms were present when Earth was primarily anoxic. Why was the appearance of cyanobacteria critical for the oxidation of the atmosphere?

You want to conduct a series of experiments involving the Hawaiian bobtail squid, so you acquired a number of eggs to incubate them under controlled laboratory conditions. However, two days after the juveniles hatched from the eggs, you find that none of them is producing bioluminescence. Why?

Metagenomics is a more sensitive analysis of community diversity than rRNA-based analyses because __________.

During an Escherichia coli-related outbreak of food poisoning on campus, 16S rRNA sequences were obtained from the stools of several infected students. Phylogenetic comparison of the sequences to those on file at the local health department and at the CDC can be used to do the following:

Why would it be an advantage for a primitive eukaryotic cell to form a mutualistic relationship with a prokaryote capable of aerobic cellular respiration?

Syntrophy is best described as…

A mutant of Rhizobium leguminosarum (a bacterium) is able to survive and reproduce in the laboratory outside of plant roots, but can no longer initiate root nodule formation. What type of genes are most likely mutated in this mutant?

Two tubes are inoculated from the same tube containing a bacterial culture. The cultures are then transferred every day for 2 months. All of the media and growth conditions are the same in every tube. After 2 months of cultivation, the fitness and genotype frequencies of the populations in the two tubes are compared. The fitness of the two cultures is the same, but the genotype frequencies are very different in the two cultures. How is this possible?