Microbiology, part 41: Genetics - Biotechnology

Hi, I'm Cathy with Level Up RN. In this video, we will be discussing some terms and concepts related to biotechnology that you likely have to know for your microbiology class. We will primarily be focused on recombinant DNA technology. At the end of the video, I'm going to give you guys a little quiz to test your understanding of some of the key facts I'll be covering, so be sure to stay for that. And if you have our Level Up RN microbiology flashcards, go ahead and pull out your flashcards so you can follow along with me. And pay close attention to the bold red text on the back of the cards because those are the things that you are likely to get tested on.

Biotechnology is the use of biological systems such as organisms to create products or services that benefit humankind. This is often achieved through genetic engineering, which involves the modification of an organism's genome to introduce desirable traits or characteristics into the organism. Recombinant DNA technology utilizes various laboratory techniques to isolate and modify DNA sequences to create new DNA combinations. A transgenic organism, which is also referred to as a genetically modified organism, is created when DNA from a different species is introduced into the organism's genome. Biotechnology has many different applications. In terms of medical applications, biotechnology is used to make insulin, the hepatitis B vaccine, interferon, which is a lab-made protein that helps patients fight cancer and infections, as well as various gene therapies. Biotechnology is also used in agriculture to create pest-resistant and/or herbicide-resistant crops. In addition, biotechnology is used to make golden rice, which is rice that contains beta-carotene. This genetically modified rice is used to improve the health of individuals in developing countries who suffer from vitamin A deficiency. Industrial applications of biotechnology include craft brewing, textile manufacturing, and the production of biofuels. Biotechnology is also used in forensics to analyze evidence such as hair, skin, and blood samples. So these are just some of the examples of how biotechnology is used in our society.

Let's now talk about some of the tools used in genetic engineering, starting with molecular cloning. Molecular cloning is a key technique where recombinant DNA is introduced into an easily manipulated host organism, such as a non-pathogenic strain of E. coli. When the bacteria replicate, this produces a population of organisms that have an identical copy of the recombinant DNA. In order to manipulate DNA molecules, scientists make use of restriction enzymes, which are also called molecular scissors. Restriction enzymes are bacterial enzymes that cut DNA at specific recognition sites that are often palindromic. So palindromic means that we have a sequence of letters that reads the same going forward as it does going backwards, such as the word mom or race car. Restriction enzymes can make a staggered cut or a straight cut in the DNA molecule. A staggered cut produces sticky ends, which are molecules with complementary overhangs. Whereas a straight cut produces blunt ends, which do not have overhangs. DNA pieces can then be joined together by DNA ligase to form a seamless DNA strand. Of note, molecules with sticky ends are more easily joined together than molecules with blunt ends because hydrogen bonds can form between complementary bases on the overhangs.

Now that you understand how restriction enzymes work, let's take a look at how recombinant DNA technology is used to produce insulin using an illustration from our microbiology flashcard deck. The insulin gene is isolated from a human cell using restriction enzymes. And here you can see the sticky ends at each end of the gene. Separately, a plasmid is removed from a bacterial cell, and it is also cut using restriction enzymes producing sticky ends. The human insulin gene is then inserted into the plasmid, forming a recombinant plasmid. This recombinant plasmid is then inserted into a bacterial cell, creating a transgenic bacterium. The transgenic bacterium then goes through a fermentation process where it replicates and produces insulin. And that insulin is then harvested and purified for medical use. As you saw in that example, the human insulin gene was inserted into a plasmid, which served as a vector to transfer a specific DNA sequence into the host cell. So plasmids are frequently used as vectors, but there are other vectors as well, including bacteriophages. In order for a plasmid to be used as a vector, it must have a multiple cloning site, which is also called a polylinker site. This is a short sequence of DNA that contains restriction enzyme sites, which allows a piece of DNA to be inserted in that region. In addition, the plasmid also has to have a selectable marker, which are genes on the plasmid that allow researchers to determine if the host cell actually took up the vector. So antibiotic resistance genes are often used as a selectable marker. Cells that have incorporated the plasmid will be able to grow and survive in the presence of the antibiotic. However, cells that have not taken up the plasmid will be destroyed by the antibiotic.

All right. It's quiz time, and I have five questions for you. Question number one, a blank organism is an organism in which DNA from a different species has been introduced. The answer is, transgenic. Number two, which bacterial enzymes are used to cut DNA at specific recognition sites? The answer is, restriction enzymes. Number three, which enzyme joins two DNA pieces together? The answer is, DNA ligase. Number four, what do you call a DNA molecule that is used as a vehicle to transfer a specific DNA sequence into a host cell? The answer is, a vector. And number five, what do you call genes on a plasmid that allow researchers to determine if the host cell has taken up a vector? The answer is, a selectable marker. Okay. That's it for this video. Hope you did great with that quiz. Thank you so much for watching, and good luck with studying.

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To create pest-resistant or-- that allow researchers to determine this genetically, then molecules.