In a bacterial cell, the three genes of the lactose operon are
A) expressed continuously.
B) expressed when lactose synthesis is required.
C) expressed only in the presence of lactose.
D) never expressed, because they are pseudogenes.
C) expressed only in the presence of lactose.
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Which of the following best describes the anatomy of a coenocytic organism?
A. The body is made of a large cell with many nuclei. B. The body cells are organized into welldefined tissue layers. C. The body cells are organized into branching filaments. D. The body is made up of several different types of highly specialized cells. E. The body is a hollow ball of flagellated cells.
The zone of soil that surrounds the roots and contains a variety of organic exudates is called the
A. mycorrhizae. B. rootsphere. C. rhizosphere. D. geosmin.
The flow volume and temperature of a stream are unaffected by ____
a. oxygen content b. rainfall c. snowmelt d. shade cast by plants e. altitude
Galactose is absent, but you find active transcription of the GAL genes. Which protein is likely mutated or absent to allow for constitutive transcription of the GAL genes?
A) Gal2 B) Mig1 C) Gal4 D) Gal10 E) Gal80