Which of the following is an example of positive gene regulation?
(A) the tryptophan gene, in which the presence of tryptophan functions as a corepressor to prevent its own transcription
(B) The lac gene in which the repress or preventing the synthesis of the enzymes that degrade lactose is deactivated by the presence of lactose
(C) CAP, which acts as a required transcription factor for the enzymes that degrade lactose
(D) inducible operons in which the inducer is a substrate
Ans: (C) CAP, which acts as a required transcription factor for the enzymes that degrade lactose
You might also like to view...
Put the following steps in the procedure for producing a karyotype in the correct order.
I. Cells are visualized under the microscope. II. Cells are stimulated to divide. III. Homologues are organized into sets by matching size and banding patterns. IV. The cells are exposed to a hypotonic solution. V. Cells are stained and placed on a microscope slide. A. I, II, IV, V, III B. II, IV, V, I, III C. IV, II, V, I, III D. IV, V, II, I, III E. II, IV, I, V, III
The presence of secretions is more comparable to endocytosis than exocytosis?
a. true b. false
Two closely related species that fail to recognize the courtship behavior of each other are said to be ________ isolated.
Fill in the blank(s) with the appropriate word(s).
The centromere
A. is a group of proteins that attach to the mitotic spindle. B. is a group of proteins that attach to the kinetochore. C. is a region of DNA where sister chromatids associate. D. is not present on the chromosomes of the daughter cells until anaphase. E. is only present when chromosomes are highly compacted.