1. Case study: Why human insulin became the first widely-used genetically engineered product
Do you know anyone with Type 1 diabetes? This disease, also known as juvenile diabetes, usually first affects people during childhood, and then persists for life. It occurs when person’s immune system attacks and destroys certain cells in their pancreas. As a result, that person can no longer produce a hormone called insulin.
Insulin, in people without diabetes, enables your body to absorb sugar into your cells, and to control your blood sugar level. The diagram at left shows how insulin works. At “1” you can see insulin binding with an insulin receptor on a cell. These receptors are found throughout many cells in the body, especially fat cells, muscle cells and certain cell in the liver. In response, these cells open up a glucose transport channel (number 3, at left). This allows glucose to diffuse into these cells, which convert the glucose into long-term energy-storage molecules such as glycogen (a polysaccharide) or fat.
(Note that there’s another form of diabetes called Type 2 diabetes. In Type 2 diabetes, a person’s pancreas still makes insulin, but the target cells stop responding to it. If you want to learn more about that disease, click this link to learn about it in our AP/College Biology curriculum.)
1.6 million Americans have type 1 diabetes. About 200,000 of these are under 20 years old. What happens when a person can’t produce insulin? Without insulin, a person can’t control their blood sugar level. Elevated blood sugar, in turn, causes damage to organs throughout the body.
Insulin’s role in type 1 diabetes has been understood since 1921. Before that, type 1 diabetes was an untreatable childhood disease. Children who developed type 1 diabetes usually died within a year or two. Once insulin’s role was discovered, doctors quickly figured out that insulin could be extracted from the pancreas of cows and pigs, which produce their own version of insulin that’s almost identical in structure to human insulin. Once insulin was available, diabetics could monitor their blood sugar levels, and inject insulin as needed. Diabetes shifted from being a death sentence to a treatable condition. (If you want to learn more about the history of insulin’s discovery, you can do so at this article from the Science History Institute or this one from the American Diabetes Association.)
Insulin from cattle and pigs was a lifesaver. But it wasn’t perfect. The tiny differences between animal and human insulin sometimes led to allergic reactions. And that’s where genetic engineering comes in.
2. Using Genetic Engineering to Create Genetically Engineered Human Insulin
Genetic engineering is the process of altering the characteristics of an organism by manipulating its genetic material.
Some argue that humans have been genetically engineering plants and animals for thousands of years through plant and animal breeding. But the kind of genetic engineering we’ll be discussing below is different: it involves direct manipulation of DNA, often by introducing genes from one species into another.
Let’s start by looking at an example of how genetic engineering is used to create insulin to treat Type 1 Diabetes. Here’s the big idea. Using genetic engineering, you can get a bacterial cell to produce a human protein, such as insulin. That human insulin can then be used by diabetics to control their blood sugar levels. Here’s how it’s made.
In the diagram at right, letter “a” is a bacterial cell. In addition to the main chromosome (b), bacterial also have small circles of DNA that are called plasmids (shown at “c”). Note that this plasmid is not drawn to scale. In reality, plasmids have only a thousandth as much DNA as the main bacterial chromosome. In nature, plasmids are used used to transfer genes between bacterial cells. This gene exchange is called conjugation. It’s sometimes referred to as “bacterial sex, but it’s quite different from sex in animals or plants. If you’re interested, you can learn more about it here in our AP Bio course.
Using techniques of genetic engineering, a plasmid can be extracted from a bacterial cell. Then, using enzymes (e) that act as a kind of molecular scissors, the plasmid can be cut open (as shown at “d”). This plasmid DNA can then be combined with DNA from another species.
In this case, that DNA would be the human insulin gene, shown at “f”. Combining a human gene with bacterial DNA creates a piece of what’s called recombinant DNA (g). Recombinant DNA is DNA that has combined from two sources. In this case, it’s a bacterial plasmid 
that contains both bacterial DNA and the human insulin gene.
Next, through a technique called transformation, the genetically engineered plasmid is re-inserted into a bacterial cell (h). Now, every time that bacterial cell reproduces, it will copy the recombinant plasmid (i). The plasmid’s DNA will also be transcribed and translated, producing human insulin (j). This human insulin can then be extracted and packaged into vials for distribution. This packaged product, in the case of genetically engineered human insulin, is called Humulin. If you know someone with diabetes, they probably use it every day. When they inject diabetic injects this genetically engineered insulin, they’re injecting the human protein…even through it was produced by a bacterial cell.
That’s one example of genetic engineering. Got it? Try answering the questions below.
3. Checking Understanding: Genetic Engineering Overview
[qwiz qrecord_id=”sciencemusicvideosmeister1961-Genetic Engineering Overview (HS)”] [h]
Genetic Engineering Overview
[i]
[q] In the diagram below, which letter represents the main bacterial chromosome?
[textentry single_char=”true”]
[c]IG I=[Qq]
[f]IEV4Y2VsbGVudC4gVGhlIG1haW4gYmFjdGVyaWFsIGNocm9tb3NvbWUgaXMgYXQgJiM4MjIwO2IuJiM4MjIxOw==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBUaGUgbWFpbiBiYWN0ZXJpYWwgY2hyb21vc29tZSBpcyB0aGUgbGFyZ2VzdCBwaWVjZSBvZiBETkEgdGhhdCB5b3UgY291bGQgZmluZCBpbiB0aGUgY2VsbC7CoA==[Qq]
[q] In the diagram below, which letter represents an unmodified plasmid?
[textentry single_char=”true”]
[c]IG M=[Qq]
[f]IE5pY2Ugam9iLsKgIFRoZSBwbGFzbWlkIGlzIGEgc21hbGwgY2lyY2xlIG9mIEROQSBpbnNpZGUgdGhlIGJhY3RlcmlhbCBjZWxsLg==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IFNvcnJ5LCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLg==[Qq]
[q] In the diagram below, which letter represents the human insulin gene?
[textentry single_char=”true”]
[c]IG Y=[Qq]
[f]IFllcy4gQWRkZWQgRE5BIGlzIGF0ICYjODIyMDtmLiYjODIyMTs=[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3QuIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEluIHRoaXMgdHlwZSBvZiBnZW5ldGljIGVuZ2luZWVyaW5nLCB0aGUgaHVtYW4gaW5zdWxpbiBpcyBiZWluZyBhZGRlZCB0byB0aGUgYmFjdGVyaWFsIHBsYXNtaWQuIFdoYXQmIzgyMTc7cyB0aGUgb25seSB0aGluZyB0aGF0IGNvdWxkIHJlcHJlc2VudCBhZGRlZCBETkE/[Qq]
[q] In the diagram below, a plasmid with recombinant DNA is shown at letter
[textentry single_char=”true”]
[c]IG c=[Qq]
[f]IE5pY2Ugam9iISBMZXR0ZXIgJiM4MjIwO2cmIzgyMjE7IHJlcHJlc2VudHMgYSByZWNvbWJpbmFudCBwbGFzbWlkLg==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBJZiBEIHJlcHJlc2VudHMgdGhlIGJhY3RlcmlhbCBwbGFzbWlkLCBhbmQgRiByZXByZXNlbnRzIHRoZSBodW1hbiBpbnN1bGluIGdlbmUsIHdoYXQgaXMgdGhlIG9ubHkgbGV0dGVyIHRoYXQgY291bGQgcmVwcmVzZW50IGEgcmVjb21iaW5hbnQgcGxhc21pZD8=[Qq]
[q] In the diagram below, which letter indicates the reproduction of genetically engineered offspring?
[textentry single_char=”true”]
[c]IG k=[Qq]
[f]IFllcyEgTGV0dGVyICYjODIyMDtpJiM4MjIxOyBzaG93cyB0aGUgb2Zmc3ByaW5nIG9mIHRoZSBnZW5ldGljYWxseSBlbmdpbmVlcmVkIHBhcmVudCBjZWxsPw==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IFNvcnJ5LCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFdoaWNoIGxldHRlciBzaG93cyB0aGUgb2Zmc3ByaW5nIG9mIHRoZSBnZW5ldGljYWxseSBlbmdpbmVlcmVkIHBhcmVudCBjZWxsPw==[Qq]
[q] In the diagram below, which letter indicates the production of genetically engineered insulin?
[textentry single_char=”true”]
[c]IG o=[Qq]
[f]IFllcyEgTGV0dGVyICYjODIyMDtqJiM4MjIxOyBpbmRpY2F0ZXMgdGhlIHByb2R1Y3Rpb24gb2YgZ2VuZXRpY2FsbHkgZW5naW5lZXJlZCBpbnN1bGluLg==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEluc3VsaW4gd2lsbCBiZSBzZWNyZXRlZCBmcm9tIHRoZSBnZW5ldGljYWxseSBlbmdpbmVlcmVkIGNlbGxzLCBhZnRlciB3aGljaCBpdCBjYW4gYmUgaGFydmVzdGVkIGZvciBkaXN0cmlidXRpb24uIFdoaWNoIGxldHRlciBzaG93cyBzb21ldGhpbmcgdGhhdCYjODIxNztzIGJlZW4gc2VjcmV0ZWQgZnJvbSBhIGNlbGw/[Qq]
[q] In the diagram below, which letter represents glucose?
[textentry single_char=”true”]
[c]IG E=[Qq]
[f]IFllcyEgTGV0dGVyICYjODIyMDthJiM4MjIxOyBpbmRpY2F0ZXMgZ2x1Y29zZQ==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEluc3VsaW4gZW5hYmxlcyBhIGdsdWNvc2UgbWVtYnJhbmUgY2hhbm5lbCB0byBvcGVuIHVwLCBhbGxvd2luZyBnbHVjb3NlIHRvIGVudGVyIHRoZSBjZWxsLiBXaGVyZSBkbyB5b3Ugc2VlIGEgbW9sZWN1bGUgZGlmZnVzaW5nIHRocm91Z2ggYSBtZW1icmFuZSBjaGFubmVsP8Kg[Qq]
[q] In the diagram below, which letter represents insulin?
[textentry single_char=”true”]
[c]IG I=[Qq]
[f]IE5pY2UhIExldHRlciAmIzgyMjA7YiYjODIyMTsgaW5kaWNhdGVzIGluc3VsaW4=[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIEluc3VsaW4gZW5hYmxlcyBhIGdsdWNvc2UgbWVtYnJhbmUgY2hhbm5lbCB0byBvcGVuIHVwLCBhbGxvd2luZyBnbHVjb3NlIHRvIGVudGVyIHRoZSBjZWxsLiBJbiBvcmRlciB0byBkbyB0aGF0LCBpbnN1bGluIGhhcyB0byBiaW5kIHdpdGggYSBtZW1icmFuZSByZWNlcHRvci4gV2hhdCBsZXR0ZXIgY291bGQgcmVwcmVzZW50IGEgbW9sZWN1bGUgdGhhdCYjODIxNztzIGJpbmRpbmcgd2l0aCBhIG1lbWJyYW5lIHJlY2VwdG9yPw==[Qq]
[q] In the diagram below, letter “a” represents the simple sugar glucose, and letter “b” represents [hangman].
[c]aW5zdWxpbg==[Qq]
[/qwiz]
4. Making Recombinant DNA
The techniques of genetic engineering were first developed in the early 1970s. The first breakthrough came about in 1971, when Paul Berg, working at Stanford University, created the first recombinant DNA molecules. As noted above, recombinant DNA is DNA that is combined from multiple sources.
To make recombinant DNA, you have to be able to cut apart DNA from at least two different sources, and then combine the DNA fragments together into a new DNA molecule. In the big picture view of genetic engineering above, I referred to enzymes that act as “molecular scissors.” These enzymes are called restriction endonucleases, or restriction enzymes. These enzymes evolved in bacteria as a defense against viral attack, and they work by snipping viral DNA into pieces. This keeps the viruses from taking over the bacterial cells that they’ve injected their DNA into. Because these enzymes restricted the ability of viruses to take over bacterial cells, they were given the name “restriction enzymes.”
Restriction enzymes can recognize specific short sequences of viral DNA (as short as a six nucleotides) and cut the DNA at a point within that sequence.
In the example at left, the restriction endonuclease HinDIII recognizes the nucleotide sequence AAGCTT, and cuts the DNA between the two As. Note that because there’s an AAGCTT on both DNA strands (running in opposite directions on the top and the bottom strand) the cut winds up being a double stranded cut, and completely severs the DNA.
Since the time of their initial discovery, over 4000 restriction enzymes have been identified. They’ve become an essential part of the genetic engineer’s toolkit. If you want to learn more about them, follow this link, which will open in a new tab.
Here’s how restriction enzymes are used to create recombinant DNA. Letter A shows a stretch of DNA, within which is the sequence GAATTC. That sequence is a restriction site (B). It’s recognized by a restriction enzyme (C), which cuts the sugar-phosphate bonds in the DNA between the nucleotide bases guanine and adenine. Just look for the red line between the G and A in the DNA.
The result is two DNA fragments (D), each with a “sticky end” (E). The ends are considered to be sticky because they contain exposed nucleotide bases that are ready to form hydrogen bonds with complementary nucleotides.
Letter “F” represents a second stretch of DNA from another species or organism that’s been cut with the same restriction enzyme. In our example of creating genetically engineered human insulin, that piece at “F” would be the human insulin gene. When that piece of DNA (F) is mixed with the DNA fragments at “D,” then the two will combine as is shown in “G.”
At this point, the DNA is held together just by the hydrogen bonds between the sticky ends of each fragment. “H” represents a gap: a missing sugar-phosphate bond that would connect the fragments into a single strand.
The last step involves a second enzyme, DNA ligase (i). DNA ligase creates sugar-phosphate bonds between adjacent nucleotides. Once ligase has done its work, you have recombinant DNA (J): DNA molecule with sequences from different species.
5. Getting the DNA for Human Insulin
Shortly after Paul Berg created the first engineered recombinant DNA, Herbert Boyer and Stanley Cohen introduced a recombinant plasmid into a bacterial cell. They took a gene for resistance to kanamycin (an antibiotic the prevents bacteria from growing), and inserted it into a plasmid. When they then inserted this modified plasmid into bacterial cells, the resulting bacteria were kanamycin resistant. In 1973, they introduced a gene from a toad into bacteria, proving that genes could be moved from animals into bacteria.
Once these techniques were developed, scientists and investors began to think about how they could profit from this technology. The huge market for insulin — millions of potential customers in the U.S. alone — made the genetic engineering of human insulin an early target of those efforts. That target was pursued by two pioneering biotechnology firms in the early 1980s: Biogen and Genentech. The goal became successful insertion of the genes for human insulin into a bacterial plasmid. But how was that human DNA to be acquired? Two techniques were used.
The first technique, pursued by Genentech, involved creating an artificial copy of the insulin gene. To do this, they started with the the primary structure of the human insulin protein (click this link to review primary structure). Knowing that structure, the scientists could work backwards to construct DNA that would code for human insulin.
The second way the insulin gene was isolated was used by Biogen. Biogen deployed a biochemical trick that evolved in a class of viruses called retroviruses. Retroviruses store their genetic information in the nucleic acid RNA, and then use an enzyme called reverse transcriptase to convert their RNA into DNA. Taking a page from this viral playbook, Biogen did the following:
- Cells that produced insulin were isolated from pancreatic tissue and grown in tissue culture.
- The messenger RNA from these cells was isolated. Then, reverse transcriptase was used to create DNA that complemented the insulin-coding RNA. In the diagram to the right, “a” is mRNA, and “b” is reverse transcriptase.
- As reverse transcriptase moves along the RNA, it lays down new DNA monomers (deoxyribonucleotides). This creates a strand that’s half RNA and half DNA (shown at “d”).
- Subsequent manipulation with additional enzymes removes the RNA, replacing it with DNA. The result is shown at “e.”
DNA made this way is called cDNA, for complementary DNA.
Both Biogen and Genentech successfully created the DNA for human insulin. But Genentech got there first. Genentech sold the licensing rights to genetically engineered insulin to the drug manufacturer Eli Lilly, the U.S.’s biggest producer of insulin.
Though Genentech won that first race, in the following years both companies developed into biotechnology powerhouses. In 2009, Genentech was acquired by an even larger biotechnology firm for $47 billion. Biogen is valued at $37 billion. The biotechnology industry, which didn’t exist 50 years ago, now directly employs over 800,000 people in the U.S, and indirectly supports about 4.7 million jobs.
6. Genetic Engineering and Recombinant DNA: Interactive Diagrams
[qwiz qrecord_id=”sciencemusicvideosmeister1961-Genetic Engineering and Recomb. DNA Diagrams (HS)”]
[h]Genetic Engineering and Recombinant DNA
[i]
[q labels = “top”]
[l]human DNA
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]unmodified plasmid
[fx] No. Please try again.
[f*] Great!
[l]recombinant DNA
[fx] No, that’s not correct. Please try again.
[f*] Correct!
[l]genetically modified bacterium
[fx] No, that’s not correct. Please try again.
[f*] Correct!
[q labels = “top”]
[l]Ligase
[fx] No. Please try again.
[f*] Good!
[l]recombinant DNA
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]restriction enzyme
[fx] No, that’s not correct. Please try again.
[f*] Excellent!
[l]sticky ends
[fx] No. Please try again.
[f*] Excellent!
[q labels = “top”]
[l]complementary DNA
[fx] No, that’s not correct. Please try again.
[f*] Good!
[l]hybrid RNA/DNA
[fx] No, that’s not correct. Please try again.
[f*] Great!
[l]reverse transcriptase
[fx] No. Please try again.
[f*] Good!
[/qwiz]
7. The Genie’s out of the Bottle
Watson and Crick described the structure of DNA in 1953. By 1973, DNA was being engineered to suit human ends. Now, using techniques very similar to those used to develop genetically engineered insulin, recombinant DNA is everywhere. It’s being deployed to create drugs to treat many diseases, including AIDS, a variety of cancers, cystic fibrosis, hemophilia, genital warts, hepatitis, and human growth hormone deficiency.
The 1980s also saw the development of the first transgenic animals: animals whose genomes were altered through insertion of genes from other species. These transgenic animals include
- Mice with human genes. These mice are widely used for research purposes.
- Goats which produce milk that contains substances that prevent formation of harmful blood clots during surgery (the drugs are extracted from the milk);
- Pigs modified with the goal that their organs can be transplanted into humans;
Transgenic plants, also referred to as genetically modified crops, have been widely in use since the 1990s. It’s estimated that in 2016, 12% of the world’s cropland was planted with genetically modified plants. (wikipedia). These include crops such as soybeans, maize (corn), and cotton, which have been modified for increased resistance to pests, and reduction of spoilage.
Transgenic crops can also have improved nutrient profiles. An example of the later is Golden Rice (wikipedia): rice that’s been genetically modified to produce beta carotene. Beta carotene is a precursor to vitamin A. Vitamin A deficiency causes hundreds of thousands of childhood deaths in regions where people consume inadequate amounts of that vitamin in their diets. In late 2019, the government of the Philippines approved Golden Rice for human consumption, making it the first Asian country to approve Golden Rice for direct use.
8. Checking Understanding: Genetically Engineered Insulin
The following quiz will help you master everything you’ve read above.
[qwiz qrecord_id=”sciencemusicvideosmeister1961-Gene Eng. Insulin, Checkin Understanding (HS)”] [h]
Genetic Engineering Quiz
[i]
[q] In the diagram below, a eukaryotic gene of interest is indicated by which number?
[textentry single_char=”true”]
[c]ID E=[Qq]
[f]IFllcy4gMSBpcyB0aGUgZ2VuZSBvZiBpbnRlcmVzdC4=[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IFNvcnJ5LCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQuIFRoZSBETkEgaXMgZ29pbmcgdG8gYmUgY3V0IHdpdGggYSByZXN0cmljdGlvbiBlbnp5bWUgdG8gaXNvbGF0ZSB0aGUgZ2VuZS4gSWYgcmVzdHJpY3Rpb24gZW56eW1lcyBhcmUgYXQgJiM4MjIwOzIsJiM4MjIxOyB0aGVuIHdoaWNoIG51bWJlciBoYXMgdG8gYmUgdGhlIGV1a2FyeW90aWMgZ2VuZSBvZiBpbnRlcmVzdD8=[Qq]
[q] In the diagram below, restriction enzymes are at which number?
[textentry single_char=”true”]
[c]ID I=[Qq]
[f]TmljZSBqb2IhIFJlc3RyaWN0aW9uIGVuenltZXMgYXJlIHJlcHJlc2VudGVkIGJ5IG51bWJlciAyLg==[Qq]
[c]ZW50ZXIgd29yZA==[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIFJlc3RyaWN0aW9uIGVuenltZXMgYXJlIHVzZWQgdG8gY3V0IEROQS4gV2hhdCYjODIxNztzIHRoZSBvbmx5IHRoaW5nIGluIHRoaXMgZGlhZ3JhbSB0aGF0IGNvdWxkIGluZGljYXRlIHNvbWV0aGluZyB0aGF0IGN1dHMgc29tZXRoaW5nIGVsc2Ugb3Blbj8=[Qq]
[q] In the diagram below, a non-recombinant plasmid (one that hasn’t yet been genetically engineered) is indicated by number
[textentry single_char=”true”]
[c]ID M=[Qq]
[f]V2F5IHRvIGdvLiBUaGUgdW5tb2RpZmllZCBwbGFzbWlkIGlzIGluZGljYXRlZCBieSBudW1iZXIgJiM4MjIwOzMuJiM4MjIxOw==[Qq]
[c]ZW50ZXIgd29yZA==[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]Tm8uIEhlcmUmIzgyMTc7cyBhIGhpbnQ6IGEgcGxhc21pZCBpcyBhIGNpcmNsZSBvZiBleHRyYS1jaHJvbW9zb21hbCBiYWN0ZXJpYWwgRE5BLiBGaW5kIHRoZSBjaXJjbGUmIzgyMzA7[Qq]
[q] In the diagram below, DNA ligase is indicated by number
[textentry single_char=”true”]
[c]ID Q=[Qq]
[f]IFllcyEgTGlnYXNlIGlzIGF0IG51bWJlciA0Lg==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBMaWdhc2UmIzgyMTc7cyBmdW5jdGlvbiBpcyB0byBjcmVhdGUgc3VnYXIgcGhvc3BoYXRlIGJvbmRzIGJldHdlZW4gRE5BIGZyYWdtZW50cy4gV2hhdCYjODIxNztzIG9uIHRoaXMgZGlhZ3JhbSB0aGF0IGNvdWxkIHJlcHJlc2VudCB0aGF0P8Kg[Qq]
[q] In the diagram below, fragments of DNA with “sticky ends” are represented by
[textentry single_char=”true”]
[c]ID U=[Qq]
[f]IEF3ZXNvbWUhIFRoZSBzdGlja3kgZW5kcyBhcmUgcmVwcmVzZW50ZWQgYnkgJiM4MjIwOzUuJiM4MjIxOw==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50OiBTdGlja3kgZW5kcyBhcmUgZXhwb3NlZCBiYXNlcyB0aGF0IHdpbGwgZm9ybSBoeWRyb2dlbiBib25kcyB3aXRoIG9uZSBhbm90aGVyLiBXaGVuIHRoZSBzYW1lIHJlc3RyaWN0aW9uIGVuenltZSBpcyB1c2VkIHRvIGN1dCBETkEsIHRoZSByZXN1bHRzIHdpbGwgYmUgZnJhZ21lbnRzIHdpdGggdGhlc2Ugc3RpY2t5IGVuZHMu[Qq]
[q] In the diagram below, a recombinant plasmid is shown at
[textentry single_char=”true”]
[c]ID Y=[Qq]
[f]IEV4Y2VsbGVudC4gVGhlIHJlY29tYmluYW50IHBsYXNtaWQgaXMgYXQgJiM4MjIwOzYuJiM4MjIxOw==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50OiBUaGUgcmVjb21iaW5hbnQgcGxhc21pZCB3aWxsIGNvbnNpc3Qgb2YgYSBodW1hbiBnZW5lICgxKSwgYW5kIHRoZSBvcmlnaW5hbCBwbGFzbWlkLg==[Qq]
[q] Organisms that have been modified to contain DNA from more than one species are called[hangman] . Often, these organisms are referred to as genetically [hangman] organisms, or GMOs.
[c]IHRyYW5zZ2VuaWM=[Qq]
[f]IEdvb2Qh[Qq]
[c]IG1vZGlmaWVk[Qq]
[f]IEV4Y2VsbGVudCE=[Qq]
[q] Enzymes used to cut DNA are called[hangman] enzymes.
[c]IHJlc3RyaWN0aW9u[Qq]
[f]IEdyZWF0IQ==[Qq]
[q] DNA [hangman]is the enzyme that connects DNA fragments by creating sugar-phosphate bonds.
[c]IGxpZ2FzZQ==[Qq]
[f]IEdyZWF0IQ==[Qq]
[q] [hangman] DNA is DNA that has been pieced together from multiple sources.
[c]IFJlY29tYmluYW50[Qq]
[f]IENvcnJlY3Qh[Qq]
[q] In the diagram below, a restriction site is shown at letter
[textentry single_char=”true”]
[c]IE I=[Qq]
[f]IEdyZWF0ISAmIzgyMjA7QiYjODIyMTsgc2hvd3MgYSByZXN0cmljdGlvbiBzaXRlLsKg[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IFNvcnJ5LCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBUaGUgcmVzdHJpY3Rpb24gc2l0ZSBpcyB3aGVyZSB0aGUgcmVzdHJpY3Rpb24gZW56eW1lcyB3aWxsIGN1dCBhcGFydCB0aGUgRE5BLg==[Qq]
[q] In the diagram below, a restriction enzyme is shown at letter
[textentry single_char=”true”]
[c]IG M=[Qq]
[f]IEV4Y2VsbGVudCEgJiM4MjIwO0MmIzgyMjE7IHNob3dzIGEgcmVzdHJpY3Rpb24gZW56eW1lLsKg[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBUaGUgcmVzdHJpY3Rpb24gZW56eW1lIGlzIHdoYXQgY3V0cyB0aGUgRE5BIGludG8gZnJhZ21lbnRzLg==[Qq]
[q] In the diagram below, “sticky ends” are shown at
[textentry single_char=”true”]
[c]IE U=[Qq]
[f]IENvcnJlY3QhIFN0aWNreSBlbmRzIGFyZSBzaG93biBhdCAmIzgyMjA7RS4mIzgyMjE7[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgJiM4MjIwO3N0aWNreSBlbmRzJiM4MjIxOyBhcmUgZXhwb3NlZCBiYXNlcywgcmVhZHkgdG8gZm9ybSBoeWRyb2dlbiBib25kcyB3aXRoIGZyYWdtZW50cyB0aGF0IGhhdmUgY29tcGxlbWVudGFyeSBzZXF1ZW5jZXMu[Qq]
[q] In the diagram below, gaps that need to be sealed together by DNA ligase are shown at letter
[textentry single_char=”true”]
[c]IE g=[Qq]
[f]IENvcnJlY3QhICYjODIyMDtIJiM4MjIxOyByZXByZXNlbnQgdGhlIGdhcHMgKGEgc3VnYXItcGhvc3BoYXRlIGJvbmQgdGhhdCBuZWVkcyB0byBiZSBjYXRhbHl6ZWQpLsKg[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBUaGUgZ2FwcyBhcmUgd2hhdCBnZXQgc2VhbGVkIGJ5IEROQSBsaWdhc2UgKHNob3duIGF0ICYjODIyMDtJJiM4MjIxOyku[Qq]
[q] In the diagram below, DNA ligase is shown at
[textentry single_char=”true”]
[c]IE k=[Qq]
[f]IENvcnJlY3QhICYjODIyMDtJJiM4MjIxOyByZXByZXNlbnRzIGxpZ2FzZS7CoA==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBMaWdhc2Ugc2VhbHMgdGhlIGdhcHMgdGhhdCBhcmUgc2hvd24gYXQgbGV0dGVyICYjODIyMDtILiYjODIyMTs=[Qq]
[q] In the diagram below, completed recombinant DNA is shown at
[textentry single_char=”true”]
[c]IE o=[Qq]
[f]IENvcnJlY3QhICYjODIyMDtKJiM4MjIxOyBpcyB0aGUgZmluaXNoZWQgcmVjb21iaW5hbnQgRE5BLg==[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLCB0aGF0JiM4MjE3O3Mgbm90IGNvcnJlY3Qu[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBSZWNvbWJpbmFudCBETkEgaXMgY29tYmluZXMgdGhlIGZyYWdtZW50cyBhdCAmIzgyMjA7RCYjODIyMTsgYW5kICYjODIyMDtGLiYjODIyMTs=[Qq]
[q multiple_choice=”true”] The enzyme responsible for creating sugar phosphate bonds between DNA fragments is / are
[c]IEROQSBwb2x5bWVyYXNl[Qq]
[f]IE5vLiBETkEgcG9seW1lcmFzZSBpcyBhIGtleSBlbnp5bWUgcmVzcG9uc2libGUgZm9yIHN5bnRoZXNpemluZyBuZXcgRE5BLiBIZXJlJiM4MjE3O3MgYSBoaW50OiBjcmVhdGluZyB0aGVzZSBzdWdhciBwaG9zcGhhdGUgYm9uZHMgaXMgY2FsbGVkICYjODIyMDtsaWdhdGlvbi4mIzgyMjE7[Qq]
[c]IFJldmVyc2UgdHJhbnNjcmlwdGFzZQ==[Qq]
[f]IE5vLiBSZXZlcnNlIHRyYW5zY3JpcHRhc2UgdGFrZXMgUk5BIGFuZCByZXZlcnNlIHRyYW5zY3JpYmVzIGl0IGludG8gRE5BLsKgSGVyZSYjODIxNztzIGEgaGludDogY3JlYXRpbmcgdGhlc2Ugc3VnYXIgcGhvc3BoYXRlIGJvbmRzIGlzIGNhbGxlZCAmIzgyMjA7bGlnYXRpb24uJiM4MjIxOw==[Qq]
[c]IFJlc3RyaWN0aW9uIGVuenltZXM=[Qq]
[f]IE5vLiBSZXN0cmljdGlvbiBlbnp5bWVzIGFyZSByZXNwb25zaWJsZSBmb3IgY3V0dGluZyBETkEgaW50byBmcmFnbWVudHMuwqBIZXJlJiM4MjE3O3MgYSBoaW50OiBjcmVhdGluZyB0aGVzZSBzdWdhciBwaG9zcGhhdGUgYm9uZHMgaXMgY2FsbGVkICYjODIyMDtsaWdhdGlvbi4mIzgyMjE7[Qq]
[c]IEROQSBs aWdhc2U=[Qq]
[f]IENvcnJlY3QhIEROQSBMaWdhc2UgY3JlYXRlcyBzdWdhci1waG9zcGhhdGUgYm9uZHMgYmV0d2VlbiBhZGphY2VudCBmcmFnbWVudHMgb2YgRE5BLg==[Qq]
[q multiple_choice=”true”] The enzyme that can synthesize DNA from an RNA template is
[c]IEROQSBwb2x5bWVyYXNl[Qq]
[f]IE5vLiBETkEgcG9seW1lcmFzZSBpcyBhIGtleSBlbnp5bWUgcmVzcG9uc2libGUgZm9yIHN5bnRoZXNpemluZyBuZXcgRE5BLg==[Qq]
[c]IFJldmVyc2UgdHJh bnNjcmlwdGFzZQ==[Qq]
[f]IE5pY2Ugam9iLiBSZXZlcnNlIHRyYW5zY3JpcHRhc2UgdGFrZXMgUk5BIGFuZCByZXZlcnNlIHRyYW5zY3JpYmVzIGl0IGludG8gRE5BLg==[Qq]
[c]IFJlc3RyaWN0aW9uIGVuenltZXM=[Qq]
[f]IE5vLiBSZXN0cmljdGlvbiBlbnp5bWVzIGFyZSByZXNwb25zaWJsZSBmb3IgY3V0dGluZyBETkEgaW50byBmcmFnbWVudHM=[Qq]
[c]IEROQSBsaWdhc2U=[Qq]
[f]IE5vLiBETkEgTGlnYXNlIGNyZWF0ZXMgc3VnYXItcGhvc3BoYXRlIGJvbmRzIGJldHdlZW4gYWRqYWNlbnQgZnJhZ21lbnRzIG9mIEROQS4=[Qq]
[q multiple_choice=”true”] The enzyme that can cut DNA into fragments is
[c]IEROQSBwb2x5bWVyYXNl[Qq]
[f]IE5vLiBETkEgcG9seW1lcmFzZSBpcyBhIGtleSBlbnp5bWUgcmVzcG9uc2libGUgZm9yIHN5bnRoZXNpemluZyBuZXcgRE5BLg==[Qq]
[c]IFJldmVyc2UgdHJhbnNjcmlwdGFzZQ==[Qq]
[f]IE5vLiBSZXZlcnNlIHRyYW5zY3JpcHRhc2UgdGFrZXMgUk5BIGFuZCByZXZlcnNlIHRyYW5zY3JpYmVzIGl0IGludG8gRE5BLg==[Qq]
[c]IFJlc3RyaWN0aW 9uIGVuenltZXM=[Qq]
[f]IEV4Y2VsbGVudC4gUmVzdHJpY3Rpb24gZW56eW1lcyBhcmUgcmVzcG9uc2libGUgZm9yIGN1dHRpbmcgRE5BIGludG8gZnJhZ21lbnRz[Qq]
[c]IEROQSBsaWdhc2U=[Qq]
[f]IE5vLiBETkEgTGlnYXNlIGNyZWF0ZXMgc3VnYXItcGhvc3BoYXRlIGJvbmRzIGJldHdlZW4gYWRqYWNlbnQgZnJhZ21lbnRzIG9mIEROQS4=[Qq]
[q] In the diagram below, a restriction enzyme is represented by letter
[textentry single_char=”true”]
[c]IG U=[Qq]
[f]IENvcnJlY3QhIExldHRlciAmIzgyMjA7ZSYjODIyMTsgaXMgYSByZXN0cmljdGlvbiBlbnp5bWUu[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[f]IE5vLg==[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBSZXN0cmljdGlvbiBlbnp5bWVzIGN1dCBvcGVuIEROQS4=[Qq]
[q] In the diagram below, HINDIII must be a [hangman] enzyme.
[c]IHJlc3RyaWN0aW9u[Qq]
[f]IEV4Y2VsbGVudCE=[Qq]
[q] In the diagram below, the DNA bases with green arrows represent[hangman] ends.
[c]IHN0aWNreQ==[Qq]
[f]IEV4Y2VsbGVudCE=[Qq]
[q] In the diagram below, a plasmid that’s been treated with a restriction enzyme is shown at
[textentry single_char=”true”]
[c]IG U=[Qq]
[c]WWVzISBMZXR0ZXIgJiM4MjIwO2UmIzgyMjE7IHNob3dzIGEgcGxhc21pZCB0aGF0JiM4MjE3O3MgYmVlbiBjdXQgb3BlbiBieSBhIHJlc3RyaWN0aW9uIGVuenltZS4=[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBBIHBsYXNtaWQgdGhhdCA=aGFzbiYjODIxNzt0IGJlZW4gdHJlYXRlZCB3aXRoIGEgcmVzdHJpY3Rpb24gZW56eW1lIGlzIHNob3duIGF0ICYjODIyMDthLiYjODIyMTs=[Qq]
[q] In the diagram below, recombinant DNA first appears at
[textentry single_char=”true”]
[c]IG Y=[Qq]
[f]IFllcyEgJiM4MjIwO0YmIzgyMjE7IGlzIGEgcmVjb21iaW5hbnQgcGxhc21pZC4=[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBMb29rIGZvciB0aGUgZmlyc3Qgb2NjdXJyZW5jZSBvZiBodW1hbiBETkEgY29tYmluZWQgd2l0aCBwbGFzbWlkIEROQS4=[Qq]
[q] In the diagram below, the first occurrence of a transgenic organism is at letter
[textentry single_char=”true”]
[c]IG c=[Qq]
[f]WWVzISBMZXR0ZXIgJiM4MjIwO2cmIzgyMjE7IHNob3dzIGEgcmVjb21iaW5hbnQgb3JnYW5pc20u[Qq]
[c]IEVudGVyIHdvcmQ=[Qq]
[c]ICo=[Qq]
[f]IE5vLiBIZXJlJiM4MjE3O3MgYSBoaW50LiBMb29rIGZvciBhIGNlbGwgdGhhdCBoYXMgYm90aCBiYWN0ZXJpYWwgRE5BIGFuZCBodW1hbiBETkEu[Qq]
[x]
[restart]
[/qwiz]
Links
- PCR – the polymerase chain reaction (the next tutorial in this module)
- Genetic Engineering (HS Level) Main Menu