0610 · 21.1Biotechnology and genetic modification

Why bacteria are useful

0:00Imagine you need to produce a useful molecule, such as an enzyme, in large quantities. You could think of a factory full of machinery, but another possibility is a population of living bacterial cells. These tiny organisms can reproduce quickly and make complex molecules. By the end of this video, you will understand why those abilities, together with plasmids and relatively few ethical concerns, make bacteria useful. Biotechnology involves using living organisms, or substances they produce, to make useful products.

0:30Genetic modification means changing the genetic material of an organism by removing, changing or inserting individual genes. These ideas are connected, but they are not identical. Using bacteria to make a useful product does not necessarily mean that the bacteria have been genetically modified. First, remember that a bacterium is a single cell. Inside it, genetic material carries instructions that influence what the cell makes and does. A gene is a length of genetic material that codes for a protein.

0:59This gives us the connection we need. A bacterial cell contains both instructions and the cellular machinery needed to make molecules. Start with rapid reproduction. Under suitable conditions, a bacterium divides to produce two bacterial cells. Those cells can divide again, so a small starting population can become a large population relatively quickly. For biotechnology, that means we can quickly obtain many cells capable of making a useful product. Think of each bacterium as a tiny working factory.

1:29Reproduction increases the number of factories, rather than simply making one factory larger. If the cells are producing a useful molecule, having more producing cells can increase the total amount made. The important link is rapid reproduction leading to a large population of producers in a short time. That only helps because bacteria can also make complex molecules. Despite being small, bacterial cells carry out many chemical reactions and manufacture molecules such as proteins, including enzymes.

1:57An enzyme is not something that becomes easy to manufacture simply because the organism making it is tiny. The bacterium already has cellular machinery capable of assembling it. These first two advantages therefore work together. The ability to make complex molecules gives each cell a useful production role. Rapid reproduction provides many cells carrying out that role. Rapid reproduction alone would not help much if the cells could not make the product we wanted.

Reproduction and ethical concerns

2:24Let us work through a simple example. Suppose a bacterial population makes an enzyme that a manufacturer wants to collect. Start with one bacterium and assume, just for this example, that every cell divides once in each round and none dies. After the first round there are two cells, and after the second there are four. After the third round there are eight cells, and after the fourth there are sixteen.

2:46We double the population each time because every existing cell produces two daughter cells. If all sixteen cells can make the enzyme, we now have sixteen potential producers instead of one. This illustrates the advantage of rapid reproduction, not a required calculation or a fixed reproduction time for bacteria. The conditions matter, too. Bacteria do not reproduce rapidly regardless of their surroundings. They need suitable conditions and a supply of nutrients.

3:13Our example assumes those requirements are met. You will see how useful microorganisms are grown and used in the video on biotechnology. Now consider ethical concerns. An ethical concern is a question about whether an action is morally acceptable, such as concern about causing suffering. Manipulating and growing bacteria generally raises fewer ethical concerns than manipulating and growing animals. Bacteria do not have a nervous system, and their use does not raise the same animal welfare concerns.

3:42However, few ethical concerns does not mean no concerns or no need for precautions. Researchers still need to consider possible harm to people and the environment. The syllabus point is specifically that there are few ethical concerns over the manipulation and growth of bacteria. It is not a claim that every use of bacteria is automatically harmless.

Plasmids and exam answers

4:01The final advantage is the presence of plasmids. A plasmid is a small, circular piece of genetic material, separate from the bacterium’s main genetic material. Plasmids can carry genes, so they can carry instructions for making particular proteins. This makes them useful tools in genetic modification. Imagine the cell’s genetic instructions as a main instruction book, with a plasmid acting like a separate instruction sheet. A useful gene can be inserted into a plasmid, which can then carry that gene into a bacterial cell.

4:31The bacterium may then use the gene’s instructions to make the desired protein. You will see the detailed process in the video on genetic modification. Keep the roles separate. The plasmid carries genetic instructions, while the bacterial cell makes the protein. A plasmid is not a tiny organ that manufactures the product by itself. Also, plasmids are separate from the main genetic material, not simply another name for it. Those distinctions explain why plasmids are useful rather than merely giving you another word to memorise.

5:01Let us connect this to an exam question. Discuss why bacteria are useful in biotechnology and genetic modification. First identify the four relevant features, then connect each feature to its usefulness. Avoid vague statements such as bacteria are small or easy to use. A strong answer names the biological feature and explains the advantage. Bacteria have a rapid reproduction rate, so large populations of producing cells can be obtained quickly.

5:28Bacteria can make complex molecules, such as proteins, that can be useful products. There are few ethical concerns over their manipulation and growth compared with those associated with animals. Bacteria have plasmids, which can carry genes into bacterial cells during genetic modification. Let us finish by bringing the ideas together. Bacteria can make complex molecules, and rapid reproduction provides many cells to make them. Their manipulation and growth raise relatively few ethical concerns, while plasmids provide a useful way to carry genetic instructions.

5:59Bacteria are useful because they combine production ability, rapid population growth and practical advantages for genetic modification.