Fish can control buoyancy by:
a. holding air in their lungs.
b. expelling air from their lungs.
c. swift movements of their opercula.
d. adjusting the amount of gas in their swim bladders.
e. inflating the chambers of their tracheae.
D
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You and a friend are student assistants in a research laboratory that investigates the anti-cancer properties of proteins isolated from marine organisms. Your friend mentions that she is using a BAC vector to insert shark DNA into Escherichia coli, but after repeated attempts, has found that the bacterial cells fail to synthesize the encoded protein. What is your advice?
A. Since shark DNA is eukaryotic, the cloning vector should be a YAC derived from yeast rather than a BAC derived from bacteria. B. If the shark DNA is unmodified, it contains introns that are not recognized by bacteria, therefore protein synthesis will not occur. C. It is impossible to clone eukaryotic DNA into a bacterial host, since eukaryotic DNA has introns and prokaryotic DNA does not. D. Because Escherichia coli is not naturally competent, it cannot serve as the cloning host for foreign DNA.
Which of the following is not a part of the general viral reproductive cycle?
A. Viral recognition of host surface proteins. B. Genome entry into the cell and immediate expression of some viral genes. C. Viral proteins are synthesized. D. Reverse transcriptase converts RNA to DNA. E. Fully assembled viruses are released.
What do sea squirts and mussels have in common?
a. both are in the same phylum. b. both have incurrent and excurrent siphons. c. both are covered in a tunic. d. both reproduce asexually. e. both attach to the substrate using the same materials.
The attempt of two organisms trying to utilize the same resource is called
A. synergy. B. parasitism. C. competition. D. interference.