Bacterial Reproduction

Contributor: Felicia Sabur. Lesson ID: 11648

Where do all those bacteria come from? They reproduce, just like everything else. Well, not quite like everything else. Learn and just be grateful that they don't always have the right conditions!

categories

Life Science

subject
Science
learning style
Kinesthetic, Visual
personality style
Lion
Grade Level
High School (9-12)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

Audio:

If bacteria were able to reproduce at their maximum rate, they would cover the entire world in a week! In order to do this, they would need constant ideal conditions, and that rarely happens. How long does it take for bacteria to reproduce?

Bacteria can reproduce as quickly as every 20 minutes, which allows for exponential growth because of how they reproduce.

They can reproduce by both asexual reproduction and sexual reproduction by conjugation.

You may be wondering what the difference is between a bacterium and bacteria. If there's only one, you call it a bacterium, and if there are more than one, you call them bacteria. The word "bacteria" is the plural form of "bacterium."

Before you continue, if you missed, or need to review, the previous seven lessons in this Viruses and Bacteria series, find them under Related Lessons in the right-hand sidebar.

Asexual reproduction is when there is only one parent involved and the offspring is identical to the parent. The bacterium makes an exact copy of itself. Bacteria reproduce asexually by binary fission, which is the process of one cell dividing in half to form two identical cells. There are five stages that the bacterium goes through during this process:

binary fission

Image by CNX OpenStax, via Wikimedia Commons, is licensed under the CC BY 4.0 license.

  • In Stage One, the bacterium makes an exact copy of its DNA.
  • During Sage Two, the bacterium cell grows longer and allows for the two molecules of DNA to separate.
  • Next, in Stage Three, a cross wall (also called a septum) begins to form in the middle and the membrane invaginates, or turns inward, and encloses the new cell in Stage Four.
  • Finally, after the septum has fully formed, the two cells separate into two new daughter cells for Stage Five.

Sexual reproduction is when there are two parents involved and they combine their genetic material to form an offspring that differs from both parents. However, sexual reproduction in bacteria does not actually result in additional offspring. Instead of more offspring, it results in more genetic diversity that is then passed on to new bacteria when they divide by binary fission. Genetic material diversity can be achieved by the three ways listed below:

Bacterial conjugation When a plasmid is shared from one bacterium to another, this creates no new bacteria, but it introduces some genetic diversity into the population.

Bacterial transformation When bacteria pick up a plasmid from the environment, this creates no new bacteria, but it introduces some genetic diversity into the population.

Bacterial transduction When a virus moves bacterial DNA from bacterium to another via viral replication cycles, this creates no new bacteria, but it introduces some genetic diversity into the population.

Feel free to pause or replay the video while filling out Lesson Eight, Bacterial Reproduction, in your Viruses and Bacteria Unit Workbook that you downloaded in Lesson One from Downloadable Resources in the right-hand sidebar. Write all of your vocabulary words down in the vocabulary section of the workbook.

Bacterial Reproduction & Exchanges of Genetic Material, from Jaya Gupta:

 

Binary fission results in a higher quantity of bacteria, but conjugation, translation, and transduction result in greater genetic diversity among the bacterial cells. Discuss with your teacher or parent how one bacterium can turn into many bacteria in a short period of time and why you think it is beneficial for the bacteria to be able to pass on new genetic material to other bacteria.

In the Got It? section, you will become the teacher!

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