Consider a mutant organism that is unable to make the amino acid arginine. Knowing that the metabolic pathway for
arginine production is ornithine ® citrulline ® arginine, you test the ability of the mutant to grow in the presence of just
one of these compounds. You find that the mutant can grow in the presence of arginine, but not in the presence of
citrulline or ornithine. From this, you can conclude that the product of the mutant gene is most directly involved in the
production of ____.
a. arginine from ornithine
b. arginine from citrulline
c. citrulline from ornithine
d. ornithine from arginine
e. citrulline from arginine
ANSWER: b
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What term describes an exotic species that thrives in a new habitat and quickly threatens the existing environment?
a. a pest species b. a keystone species c. an advanced predator species d. an invasive species
These two homologous chromosomes have ___ alleles in common and differ by ___ alleles
1.1, 3
2.2, 2
3.3, 1
4.4, 0
Some general evolutionary change trends in animals include:
a. lower surface area to volume ratio, radial symmetry, mutualism with photosynthetic organisms. b. larger body size, bilateral symmetry, and growth by continuous addition to skeletal elements. c. bilateral symmetry, chitinous cell walls, ability to digest cellulose. d. radial symmetry, motility, filter feeding. e. greater surface area to volume ratio, radial symmetry, diffusion to move nutrients in the body.
Twenty-three years separated Darwin's return from his voyage on the HMS Beagle and his publication of On the Origin of Species. What is the reason(s) for this gap?
a. Darwin knew his ideas were revolutionary and he wanted a strong case before unveiling them. b. Darwin worked to amass a great body of both observational and experimental evidence in support of his theory. c. Competition pressured Darwin into publishing. d. B and C, but not A.