Question

A bacterial cell can donate DNA during conjugation when it a. produces competence factors. b. contains an \(F\) factor. c. is virulent. d. has been infected by a bacteriophage. c. All of the above allow a bacterial cell to donate DNA during conjugation.

Short answer

Option (b) is the correct answer, because the \(F\) factor allows a bacterial cell to donate DNA during bacterial conjugation.

Step-by-step solution

Analyzing the Options

Option (a) refers to competence factors, which are mostly about taking up DNA from surroundings, so this is unrelated to donating DNA in the context of conjugation. Option (b) refers to the \(F\) factor- a type of plasmid that contains genes necessary for the process of sex pilus formation and DNA transfer during bacterial conjugation. Option (c) is about virulence, the ability of a microorganism to cause disease. This is more related to infectivity rather than donating DNA. Option (d) being infected by a bacteriophage can lead to transduction, not conjugation.

Selecting the Correct Option

Based on the analysis, it is clear that option (b) is the correct answer, because only the \(F\) factor is directly linked with the process of DNA donation during bacterial conjugation.

Discard the Options which are incorrect

Options (a), (c) and (d) can be discarded because they are not directly related to DNA donation in bacterial conjugation. While competence factors, virulence and infection by bacteriophage have significant roles in bacterial gene transfer and other processes, they are not concerned with DNA donation during bacterial conjugation.

Key concepts

F factor

At the heart of bacterial conjugation is the 'F factor', also known as the fertility factor. This fascinating genetic element resides within certain bacteria, giving them the status of 'F+' cells. These special cells can donate genetic material to 'F-' cells during conjugation, a unique bacterial dating dance.

What makes the F factor tick are genes that encode the machinery for conjugation – specifically, the sex pilus. This cellular appendage reaches out from an 'F+' bacterial cell to connect with an 'F-' recipient. Once the two cells are cozily connected, the F factor or parts of it can be transferred. The recipient cell, once merely 'F-', becomes 'F+' and gains the ability to initiate its own acts of conjugation.

But why does this matter? The implications are enormous in the bacterial world. With the transfer of the F factor, a recipient bacterium not only gains the potential to share genes but also can acquire new abilities, such as resistance to antibiotics. This underscores the importance of the F factor in both microbial evolution and the spread of antibiotic resistance.

Plasmids

Imagine tiny circles of DNA harboring extra goodies not found in the main bacterial genetic manual – these are plasmids. Found in many bacteria, these DNA molecules are like the optional side quests in a video game, offering unique genes for various powers and abilities.

Plasmids come in different flavors, and the F factor is a prime example. Not all plasmids carry genes for conjugation; some might have genes for resistance to antibiotics or the ability to digest rare nutrients. What's interesting is that plasmids replicate independently of the bacterial chromosome and can be passed on during cell division, ensuring their genetic message lives on.

Plasmids are pivotal for synthetic biology and biotechnology, too. Scientists often use them as tools to introduce new genes into bacteria, brewing up medical products like insulin or even vaccines. Understanding plasmids is crucial for biomedicine and for grasping bacteria's survival strategies.

Gene Transfer in Bacteria

Bacteria have a knack for survival, partly due to their gene-swapping prowess. Gene transfer in bacteria is not just a bonus—it's a key feature of their evolutionary success. Aside from conjugation facilitated by factors like the F plasmid, bacteria exchange DNA through other methods, too.

Transformation is one method where bacteria pick up stray DNA fragments from the environment, a bit like beachcombers finding treasures on the shore. Another method is transduction, where viruses – the Trojan horses of the microbial world – smuggle in DNA from other bacteria they've infected.

Why all this gene transferring hustle and bustle? It's simple: adapt or die. Bacteria gain new abilities, from metabolizing exotic foods to dodging antibiotics like tiny Houdinis. This gene transferring business, while advantageous for bacteria, can pose challenges for us, particularly when it leads to the rise of antibiotic-resistant superbugs. Hence, understanding bacterial gene transfer is not just academic—it's a pressing issue for human health.