Chemical reactions involving ________ have been proposed as energy-yielding reactions for primitive organisms
A) Fe, O2, and H2
B) S, O2, and H2
C) S, and O2
D) S, and H2
Answer: D
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Define these terms:
(a) negative pressure inhalation: (b) positive pressure exhalation:
A microbe is discovered growing near a deep sea thermal vent. When researchers bring a sample up to the surface and try to grow it in a lab at room temperature in a normal incubator, they are unsuccessful. Why?
A. The pressure isn't the same at sea level as it is on the ocean floor. B. Oxygen concentrations are very different between the two environments-it's possible the microbe is a strict anaerobe and is poisoned by the air (oxygen) in the lab. C. Salt concentrations might be different in the media the researchers are attempting to use and the salt water the microbe is used to living in. This might be causing osmotic pressure differences that the microbe can't tolerate. D. The temperature is probably different-the thermal vent would be very hot, while these researchers are trying to grow this microbe at room temperature. The enzymes in the cells are probably outside of their normal operating range at room temperature, and therefore nonfunctional. E. All of the above.
The development of a blood substitute would be welcomed for all of the following reasons EXCEPT which one?
A) Human blood may carry and transmit infectious agents. B) Human blood storage requires refrigeration, which might not be available in developing countries. C) The supply of donated human blood generally cannot keep up with the demand. D) Transfused blood rarely persists for more than a few days in the recipient. E) Typing and cross-matching are necessary with human blood, and the right type may not be available.
A hypothetical community on a barren mid-Atlantic island consists of two fish-eating seabirds (the booby and the noddy), the fungi and microorganisms that live on the birds' dung, a tick that feeds on these two birds, a cactus, a moth that feeds on
cast-off feathers, a beetle that lives on dung organisms, and spiders that eat the other arthropods. There are no other plants and no lichens. Which pair of organism and trophic structure is incorrect? A) fungi—detritivores B) booby—primary consumer C) moth—detritivore D) cactus—producer