The catabolite repression system in E. coli essentially represses the lac operon when glucose is present. What evolutionary advantage would favor evolution of such a system?
What will be an ideal response?
Glucose can enter glycolysis "as is," whereas lactose must first be split into glucose and galactose. To do so, the energy-requiring synthesis of ?-galactosidase is required. It is more energy efficient to burn glucose than lactose.
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Which phylum is most closely related
developmentally to the first vertebrates? a. Echinodermata b. Arthropoda c. Mollusca d. Annelida e. none of these
Which type of tissue is able to contract?
A) epithelial B) loose connective C) dense connective D) muscle E) nervous
How many of these species probably have a cell wall that consists partly of an outer membrane of lipopolysaccharide?
A) only one species B) two species C) three species D) four species
Volvox and Paramecium share which characteristic?
A) photosynthetic ability B) true multicellularity C) anaerobic respiration D) movement