Freshwater flatworms have a _______ system that is primarily important in osmoregulation, so you would expect the urine in these tubules to have an osmolarity ____ the osmolarity of the body fluids.
A. protonephridial, lower than
B. protonephridial, higher than
C. metanephridial, lower than
D. metanephridial, higher than
E. protonephridial, similar to
A. protonephridial, lower than
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Marine teleost fishes deal with the osmotic stress of living in seawater mainly by ____
a. active transport of ions into the body through the gills b. excreting nitrogenous wastes through their kidneys as urea c. active transport of ions out of the body by chloride cells d. excreting excess salt through the actions of specialized salt glands in their heads e. maintaining high levels of urea and trimethylamine oxide in body fluids
You want to study divergence of populations, and you need to maximize the rate of divergence to see results within the period of your grant funding
You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed. What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2. Choose individuals from one extreme to form the new population. 3. Choose a species to study that produces many offspring. 4. Choose a species to study that produces a few, large offspring. 5. Place the new population in the same type of environment as the source population. 6. Place the new population in a novel environment compared to that of the source population. A) 1, 3, and 6 B) 1, 4, and 6 C) 2, 3, and 5 D) 2, 3, and 6
A substance was added to a cell culture that inactivated the tRNA in the cell. Which is the best prediction of what will occur in this cell culture?
A) Amino acids will not form proteins. B) Ribosomes will not form. C) DNA will not be copied. D) Transcription will not occur.
In general, termination of transcription
a. occurs at a specific site that is stable to changes in temperature. b. requires transcription of the sequences signaling termination. c. is unaffected by sequences that are not in proximity to the termination site. d. is triggered by RNA polymerase's interaction with DNA sequences. e. requires accessory proteins.