The sixth amino acid in normal hemoglobin is
glutamate, but it is replaced by __________ in
sickle-cell anemia.
a. histidine
b. proline
c. leucine
d. valine
e. threonine
Answer: d
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True or false: Decline of a predator population in an area affects only the prey population on which it feeds
A. true B. false
Which of the following statements regarding the loss of biodiversity is false?
A. Earth is losing 2.5% of its species annually. B. There will be fewer species at the end of the 21st century than there are now. C. Loss of biodiversity results in the loss of novel compounds with potential medical applications. D. Loss of biodiversity may result in less productive and resilient communities. E. Habitat degradation is one of the most important threats to biodiversity.
The first plant to colonize the plains of Mt St
Helens after this volcano erupted in 1980 was a prairie lupine. The prairie lupine is an example of
a. a secondary successor. b. a pioneer species. c. a keystone species. d. an exotic species. e. more than one of these.
Vials of microorganisms that undergo the freeze-drying process, called ________, will remain preserved and viable for years.
A. sterilization B. pasteurization C. desiccation D. lyophilization E. flash freeze