Which of the following is a function of a signal peptide?
A. to bind RNA polymerase to DNA and initiate transcription
B. to signal the initiation of transcription
C. to terminate translation of the messenger RNA
D. to translocate polypeptides across the ER membrane
E. to direct an mRNA molecule into the cisternal space of the ER
Ans: D. to translocate polypeptides across the ER membrane
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Which of the following is not a type of bacterial DNA recombination?
A. Transformation B. Transduction C. Conjugation D. Mitosis
Which of the following statements are true regarding bacteria in the human body? Select all correct choices
A. Human bodies can contain pathogenic bacteria, but these are often kept in check by other (non-pathogenic) species. B. Human bodies can actually contain bacteria that are beneficial to certain processes (e.g., digestion). C. The TB-causing bacteria M. tuberculosis is present (but dormant) in many human bodies.
The osmotic potential of a plant refers to the
A) force exerted outward on a cell wall by the water contained in the cell. B) surfaces of larger molecules, such as those in the cell walls, exerting an attractive force on water. C) association between concentrations of solutes in cells and the rate of water loss. D) ratio of carbon fixed (photosynthesis) per unit of water lost (transpiration).
Coral reefs are
A) shells of Mollusca that have been converted to rock by geological processes. B) hard external skeletons secreted by coral animals (Cnidaria). C) marine rocks that often are used as attachment places by Cnidaria. D) hardened sugars that are secreted by algae.