Which statement best describes an Escherichia coli (E. coli) cell that is F+?

• A. It is incapable of forming pili for genetic exchange.
• B. It lacks the F plasmid and can only receive DNA during conjugation.
• C. It is resistant to all antibiotics due to the F factor.
• D. It possesses the F plasmid and can act as a donor during conjugation.

Answer: (D)

Verified step by step guidance

1. Understand the role of the F factor (fertility factor) in Escherichia coli. The F factor is a plasmid that carries genes responsible for the formation of pili and the ability to transfer genetic material during conjugation.
2. Recall that an E. coli cell that is F+ contains the F plasmid, which enables it to produce sex pili. These pili are essential for establishing contact with an F- cell to initiate conjugation.
3. Recognize that an F+ cell acts as a donor in conjugation, transferring a copy of the F plasmid to an F- recipient cell, which lacks the F plasmid.
4. Note that the presence of the F plasmid does not inherently confer antibiotic resistance; antibiotic resistance depends on other genes that may or may not be present on the plasmid.
5. Conclude that the best description of an F+ E. coli cell is that it possesses the F plasmid and can act as a donor during conjugation.