Describe how DNA is transferred from a donor F-positive to a recipient F-negative cell
What will be an ideal response?
Ans: The TraY protein binds to an origin of transfer site, oriT, on the F plasmid. This causes the protein TraI to bind. TraI is a relaxase that nicks the DNA, attaches to the 5′ end, and unwinds the nicked strand from its complement. This strand passes to the recipient cell, leaving a single circular strand in the donor cell. Both strands are duplexed by DNA replication, and the recipient cell's DNA recircularizes to result in one complete F plasmid in each of the two cells.
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The degree of turbidity in a broth culture correlates to the amount of cell growth.
Answer the following statement true (T) or false (F)
The medical term for a collapsed lung is
a. hemothorax. b. hydrothorax. c. planothorax. d. pneumothorax. e. brachiothorax.
Refer to Figure 46-2. Which of these lungs would be best for an animal that is fairly active?
a. 1 b. 2 c. 3 d. 4 e. All of the lungs would offer the same amount of gas exchange.
Which of the following statements regarding lateral gene transfer is INCORRECT?
a) Lateral gene transfer increases the genetic variability of species. b) Lateral transfer makes it difficult to identify the boundaries of different bacterial species. c) With the exception of the endosymbiosis events that gave rise to mitochondria and chloroplasts, lateral gene transfer does not occur in eukaryotes. d) Lateral transfer can occur through the ability of some species to absorb naked DNA fragments from the environment. e) Lateral gene transfer is rarely mediated by viral infections.