Suppose that a mutant organism is unable to make the amino acid arginine. Knowing that the metabolic pathway to production of arginine is ornithine ? citrulline ? arginosuccinate ? arginine, you test the ability of the mutant to grow in the presence of each one of these compounds, providing just one of the compounds in each of your tests. Also suppose that you find that the mutant can grow in the presence of arginosuccinate or arginine, but NOT in the presence of citrulline or ornithine. From this information, which step in the metabolic pathway do you think is blocked?
a. citrulline to arginosuccinate
b. arginosuccinate to arginine
c. ornithine to citrulline
d. ornithine to arginosuccinate
Ans: a. citrulline to arginosuccinate
You might also like to view...
Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration.
Answer the following statement true (T) or false (F)
Tracheophyte plants are characterized by all of the following except
A. specialized conducting systems. B. waxy cuticle. C. stomata. D. homospory or heterospory. E. seeds.
Companion cells load most of the carbohydrates into sieve tube members ____
a. through plasmodesmata b. by osmosis c. by antiport
d. through carrier proteins e. by symport
The ________ of liquid water is created through the property of cohesion.
a. adhesion b. surface tension c. heat capacity d. temperature regulation