F plasmid

An F’ plasmid is an F plasmid that picked up a piece of bacterial chromosomal DNA. In Microbiology, it matters because it can move those genes into another cell during conjugation.

What is F plasmid?

An F’ plasmid is a bacterial plasmid that started as an F plasmid, then accidentally picked up extra chromosomal DNA from the host cell. In Microbiology, that makes it a special kind of donor DNA carrier, not just a fertility factor. The prime symbol in F’ tells you the plasmid is the F factor plus added bacterial genes.

The F factor normally contains genes for conjugation, including the machinery needed to build a pilus and transfer DNA to another bacterium. When the F plasmid integrates into the chromosome, it becomes an Hfr cell, which can transfer chromosomal genes. If the integrated F factor later excises incorrectly, it can take nearby host genes with it. That mixed plasmid is the F’ plasmid.

Because it still carries the F genes, a cell with an F’ plasmid can act as a donor cell during conjugation. The big difference is that the plasmid now delivers both its own transfer genes and the bacterial genes it picked up from the chromosome. After transfer, the recipient may become F’ as well, which means the added genes can spread through a bacterial population.

This is one reason F’ plasmids show up in lessons on horizontal gene transfer and genetic diversity in asexual prokaryotes. Bacteria do not need sexual reproduction to exchange DNA. They can move genes by conjugation, transformation, or transduction, and F’ plasmids are a clear example of how DNA can jump from one cell to another in a way that changes traits fast.

A common class example is antibiotic resistance. If the extra DNA on an F’ plasmid includes a resistance gene, the recipient cell may survive an antibiotic that would normally kill it. That can make a small DNA transfer matter a lot in a lab culture or in a real infection.

Why F plasmid matters in MICROBIO

F’ plasmids show how bacteria gain new traits without making offspring through sex. That makes them a clean example of horizontal gene transfer, one of the main ways prokaryotes build genetic diversity even though they reproduce asexually.

This term also connects the structure of a plasmid to the trait it carries. You are not just memorizing that a plasmid exists. You are tracing how an F plasmid can pick up chromosomal DNA, move that DNA into another cell, and change what that cell can do. That sequence matters when you explain why traits like antibiotic resistance spread so quickly in bacterial populations.

F’ plasmids also help you separate three related ideas that often get mixed up: F+ cells, Hfr cells, and donor cells carrying extra chromosomal genes. If you can tell which DNA is being transferred and whether the recipient becomes F+, F’, or recombined, you understand the mechanism instead of just the vocabulary.

In lab or class discussions, this term shows up any time you are asked to predict what a transfer event does to genotype and phenotype. It is a good checkpoint for whether you can connect gene movement to real outcomes like survival, adaptation, and variation.

How F plasmid connects across the course

Conjugation

F’ plasmids move through conjugation, the direct cell-to-cell transfer of DNA in bacteria. If you understand conjugation, you can track how the donor forms a physical connection, copies DNA, and passes genetic material to a recipient. F’ plasmids are one specific type of DNA cargo that can be moved this way.

Horizontal Gene Transfer

F’ plasmids are a classic example of horizontal gene transfer because DNA moves between cells, not from parent to offspring. That is the big idea behind how bacteria pick up new traits quickly. When you see horizontal gene transfer in a question, an F’ plasmid is one possible mechanism to consider.

F+ cell

A cell with an ordinary F plasmid is F+, meaning it can donate DNA for conjugation. An F’ cell is also a donor, but it carries extra chromosomal genes attached to the F factor. That extra DNA is what makes F’ more interesting than a basic F+ cell in genetics problems.

Antibiotic Resistance Genes

If an F’ plasmid carries antibiotic resistance genes, those genes can spread from one bacterium to another. That connection is why plasmids matter in medicine and public health. In a problem or case study, a transfer event can explain why a bacterial strain suddenly survives a drug treatment.

Is F plasmid on the MICROBIO exam?

A quiz question might show a donor bacterium with an F’ plasmid and ask what happens after conjugation. Your job is to trace the DNA transfer, identify the donor and recipient, and predict whether the recipient gains the extra genes on the plasmid. If the prompt includes antibiotic resistance, connect the genotype change to survival in the presence of the drug.

In a lab write-up or data table, you might compare colony growth before and after plasmid transfer, then explain the phenotype shift using conjugation and horizontal gene transfer. A diagram question may ask you to spot the pilus, the donor cell, or the plasmid carrying chromosomal DNA. The best answers name the mechanism and the outcome, not just the term.

F plasmid vs F+ cell

An F+ cell has the fertility factor, but it does not carry extra chromosomal DNA attached to it. An F’ plasmid is different because it includes the F factor plus host genes that were accidentally picked up from the chromosome. If a question asks which one can move additional bacterial genes during conjugation, the answer is F’.

Key things to remember about F plasmid

• An F’ plasmid is an F plasmid that carries extra bacterial chromosomal DNA.

• It forms when the integrated F factor excises incorrectly and takes nearby host genes with it.

• Because it still has the F genes, an F’ plasmid can act as a donor during conjugation.

• F’ plasmids are a simple way to see how bacteria gain new traits through horizontal gene transfer.

• If the extra DNA includes antibiotic resistance genes, the transfer can change bacterial survival fast.

Frequently asked questions about F plasmid

What is F’ plasmid in Microbiology?

An F’ plasmid is a bacterial plasmid made when the F factor picks up extra chromosomal DNA from its host. It can still transfer DNA during conjugation, so it acts as a donor that moves both fertility genes and the extra bacterial genes.

How does an F’ plasmid form?

It usually forms after the F factor integrates into the bacterial chromosome and later excises incorrectly. If the cut is sloppy, the plasmid carries nearby chromosomal DNA with it. That mistake creates the F’ plasmid.

Is an F’ plasmid the same as an F+ cell?

No. An F+ cell has the fertility plasmid, but an F’ plasmid also contains extra bacterial DNA from the chromosome. That extra DNA is what makes F’ different and what can be transferred to another cell.

Why does an F’ plasmid matter in bacteria?

It gives bacteria another way to spread useful genes, including antibiotic resistance genes. In Microbiology, it is a good example of horizontal gene transfer and a reason bacterial populations can change traits quickly.