Binary Fission - Online Tutor, Practice Problems & Exam Prep

Binary fission is a prokaryotic asexual reproduction process where a single parental cell divides into two genetically identical daughter cells. The process involves four key steps: elongation of the cell envelope and DNA replication, separation of replicated DNA and septum formation, complete septum formation, and final separation into two daughter cells. The time taken for binary fission is known as generation time, which varies among organisms. Understanding this process is crucial for grasping microbial growth and reproduction.

Binary Fission

In this video, we're going to begin our lesson on binary fission. Recall from our previous lesson videos that prokaryotes or prokaryotic organisms replicate by the process of binary fission. But eukaryotes do not divide by binary fission. Recall that eukaryotes divide by mitosis. Now, binary fission can be defined as prokaryotic asexual reproduction, meaning that there's only one single parental cell that will divide to form 2 new daughter cells. And the term daughter cells refers to either of the 2 final cells that form after a cell divides.

If we take a look at our image down below, notice on the left-hand side, we're showing you our parental prokaryotic cell. Notice that its chromosome, which is here in blue, is not within a nucleus. It is a circular chromosome. This is a prokaryotic cell. This single parental prokaryotic cell, when it's ready to divide, will divide by the process of binary fission. The process of binary fission allows this single parental cell to divide into 2 daughter cells. We can label these here the daughter cells.

Once again, the daughter cells are the final cells that result from binary fission. This process of binary fission actually contains a few critical steps that include replicating the chromosome so that each of the daughter cells is able to get a copy of the chromosome. We'll be able to talk about some of the steps of binary fission in our next lesson video. But for now, this concludes our brief introduction to binary fission, and I'll see you guys in our next video.

Steps of Binary Fission

In this video, we're going to focus on the steps of binary fission. Binary fission actually occurs in a series of steps that can be consolidated down to just 4 steps, and notice that we have each of those 4 steps numbered down below in the text, and each of these numbers for each of the steps corresponds with the numbers for the steps that are down below in the image. Now, in the very first step of binary fission, the cell is going to elongate its cell envelope. So the cell wall and its cell membrane are all going to elongate. And the cell is going to be increasing in its overall size. And all of this is going to happen as the DNA within the cell is going to get replicated, which means that the DNA is going to end up getting copied so that there are 2 identical copies of the DNA. If we take a look at our image down below at step number 1, notice that on the far left we have our prokaryotic parental cell, and it only has one copy of the chromosome. However, in the first step of binary fission, the cell is going to elongate its cell envelope. And so the cell wall and cell membrane are all elongated in comparison to the original parental cell. And as the cell is elongating, the DNA within the cell is also going to be replicated so that there are 2 identical copies of the DNA. Notice here, in this part of the image, we have the replicating chromosomes. So you can see this is the original chromosome and branching off of the original chromosome over here is going to be the other chromosome that is being formed.

Now in step number 2, after the replication of the DNA, the replicated DNA is going to end up moving towards opposite ends of the cell as a structure known as the septum begins to form. The septum is really just this structural partition, basically a divider that forms within the cell. It forms at the center of a dividing cell to end up separating the two resulting cells. If we take a look at step number 2, notice that the chromosomes are going to separate after replication. So this is the original one and this is the copied one over here. And notice that they are separating into their separate cells. You can see here that there's a structure that's beginning to form that's known as the septum. So here we can say that the septum is beginning to form. Once again, the septum is this structure that is going to end up forming and dividing the cell.

So in step number 3, the septum is going to completely form and create 2 separate cells that are still connected. Taking a look at step number 3, notice that the septum is completely formed. The septum, once again, is this structural partition, this divider that forms to separate the 2 cells. This cell is separating from this cell over here.

Now in step number 4, the cells are going to completely separate from each other into 2 identical daughter cells. Identical means that these two cells are genetically identical. They have exactly the same DNA. If we take a look at step number 4 here in our image, notice that we're saying that the identical daughter cells are going to separate from one another. You can see here that this daughter cell is completely separate from this daughter cell over here, and they are identical to each other genetically because they have exactly the same DNA, one that has been copied from the other. Really, this is the process of binary fission, starting with a single prokaryotic parent cell and ending with 2 identical prokaryotic daughter cells. The actual amount of time that it takes for a cell to undergo binary fission is going to vary. And that specific amount of time that it takes for a cell to undergo binary fission is referred to as the generation time. How long does it take to create a new generation of cells? We'll be able to talk a lot more about this generation time later in a different video. But for now, this here concludes our steps of binary fission, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

The cellular process by which two bacterial daughter cells arise from one bacterial parent cell is known as:

• A. Conjugation
• B. Meiosis
• C. Binary fission
• D. Mitosis

The partition between daughter cells that is a result of the inward growth of the bacterial cell wall from opposite directions is known as the:

• A. Z-ring
• B. Septum
• C. Fission wall
• D. Dividing factor

The time required for a cell to undergo binary fission is called the:

• A. Growth phase
• B. Duplication time
• C. Fission time
• D. Generation time

Here’s what students ask on this topic:

What is binary fission and how does it differ from mitosis?

Binary fission is a form of asexual reproduction in prokaryotes where a single parental cell divides into two genetically identical daughter cells. The process involves four key steps: elongation of the cell envelope and DNA replication, separation of replicated DNA and septum formation, complete septum formation, and final separation into two daughter cells. In contrast, mitosis is a process of cell division in eukaryotes that results in two genetically identical daughter cells. Mitosis involves more complex steps, including prophase, metaphase, anaphase, and telophase, and requires the formation of a mitotic spindle. Unlike binary fission, mitosis occurs in cells with a nucleus and involves linear chromosomes.

What are the steps involved in binary fission?

Binary fission involves four key steps: 1) Elongation of the cell envelope and DNA replication: The cell wall and membrane elongate, and the DNA is replicated to form two identical copies. 2) Separation of replicated DNA and septum formation: The replicated DNA moves to opposite ends of the cell, and a septum begins to form. 3) Complete septum formation: The septum fully forms, creating two separate but connected cells. 4) Final separation: The two daughter cells completely separate, each being genetically identical to the original parental cell. This process ensures that each daughter cell receives an identical copy of the DNA.

How long does binary fission take and what factors influence its duration?

The time taken for binary fission, known as generation time, varies among organisms and is influenced by several factors, including nutrient availability, environmental conditions, and the specific type of prokaryote. For example, under optimal conditions, Escherichia coli can divide every 20 minutes, while other bacteria may take several hours. Temperature, pH, and the presence of inhibitory substances can also affect the generation time. Understanding these factors is crucial for studying microbial growth and reproduction in different environments.

Why is binary fission important for prokaryotic organisms?

Binary fission is crucial for prokaryotic organisms because it allows for rapid and efficient reproduction, enabling them to quickly colonize environments and adapt to changing conditions. This process ensures genetic consistency, as the daughter cells are genetically identical to the parental cell, which is essential for maintaining the species' characteristics. Additionally, binary fission contributes to the genetic stability of prokaryotic populations, allowing them to thrive in diverse and often harsh environments.

What is the role of the septum in binary fission?

The septum plays a critical role in binary fission by acting as a structural partition that divides the parental cell into two daughter cells. During the process, the septum begins to form at the center of the cell after the DNA has been replicated and moved to opposite ends. It continues to develop until it completely separates the two cells. The formation of the septum ensures that each daughter cell receives an identical copy of the DNA and is essential for the successful completion of binary fission.