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What would happen if a target cell’s receptor for a signal was missing or defective?

Phylum porifera (sponges) feed by:

The adaptive advantage of the thin, filamentous structure of fungal mycelia is that it…

Which of the following does not occur during the light dependent reactions of photosynthesis?

What do cartilaginous (ex. skarks) and bony fishes have in common?

Which of the following groups is most closely related to vertebrates?

How does aerobic cellular respiration compare to fermentation in eukaryotes?

What protist is most closely related to animals?  

Consider the cyanobacteria Nostoc. Individual cells grow attached to each other in long chains produced from binary fission with cells remaining attached (e.g., streptococcus). Most perform photosynthesis, using photosystems I and II to generate ATP and NADPH that they use to power the fixation of carbon dioxide via the Calvin cycle. However, a small number form heterocysts, cells that instead of performing photosynthesis, fix nitrogen into ammonium. Heterocysts share their nitrogen compounds with their photosynthetic neighbors, who in turn share sugars with the heterocysts. If you extracted and analyzed all the mRNA from a single heterocyst and all the mRNA from a single photosynthetic cell and compared both sets of mRNA, would you find mRNA that is different between these two cell types, photosynthetic and nitrogen fixing heterocyst? If so, what would it represent?

Consider the following binary tree.   a)  Give the results of traversing the tree in post-order fashions (3 points). b)  Give the results of traversing the tree in pre-order fashions (3 points).