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Biology - Recombinant DNA and Biotechnology

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    Study Guide Biology – Recombinant DNA and Biotechnology 1. Recombinant DNA Recombinant DNA biotechnology is a way scientists use what we know about DNA to solve real - world problems. At its core, it involves changing an organism’s genes to give it new abilities or traits that are useful to humans. 1.1 Biotechnology and Genetic Engineering Biotechnology is often called genetic engineering because it involves changing an organism’s genes. When scientists add, remove, or modify genes, the organism’s DNA becomes recombined . This newly formed DNA is called recombinant DNA . In simple terms, recombinant DNA is DNA that has been altered by combining genetic material from different sources. 1.2 Why Recombinant DNA Is Important Recombinant DNA allows cells to make proteins they would not normally produce . These proteins can be used to: • Make medicines , such as insulin • Develop vaccines • Improve human health by treating or preventing diseases 1.3 Using Recombinant DNA in the Environment Bacteria containing recombinant DNA can also be used outside the laboratory, but only under carefully controlled conditions . These modified bacteria can: • Improve soil fertility • Act as insecticides to protect crops • Help clean up pollution in the environment

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    Study Guide 1.4 Transgenic Organisms An organism that carries extra genes from another organism is called transgenic . Scientists have created: • Transgenic bacteria • Transgenic plants • Transgenic animals These organisms are designed to perform useful tasks, such as growing faster, resisting pests, or producing helpful substances. 1.5 Gene Modification in Humans Human cells can also be genetically modified. By adding or correcting specific genes, cells can be made to produce proteins that help treat health - related deficiencies . This approach is especially important in modern medical research and therapy. 1.6 The Role of Genomics Scientists can modify genes because of advances in genomics . Genomics is the study of an organism’s entire set of chromosomes , including: • How genes function • How species have evolved over time 1.7 Genome Sequencing and Its Impact In 2003 , scientists completed the sequencing of the human genome . Since then, many other organisms have been sequenced, including: • Prokaryotes , such as E. coli • Eukaryotes , including both vertebrates and invertebrates

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    Study Guide By comparing genomes from different organisms, scientists gain a deeper understanding of: • Genetic similarities • Evolutionary relationships • How life on Earth is connected at the molecular level 2. Pharmaceutical Products Biotechnology plays a major role in making important medicines that help people with genetic disorders and serious diseases. Many health problems happen when the body cannot make certain proteins. Thanks to biotechnology, scientists can now produce these missing proteins in the laboratory and use them as treatments. 2.1 Treating Protein Deficiencies Some human gene defects prevent the body from producing essential proteins. For example: • Insulin deficiency leads to diabetes • Human growth hormone deficiency causes dwarfism • Factor VIII deficiency results in poor blood clotting Today, these proteins can be replaced using proteins made through biotechnology , instead of relying on natural sources. 2.2 How Insulin Is Made Using Biotechnology Insulin is made up of two protein chains . Scientists place the genes for these two chains into small DNA rings called plasmids , which are inserted into bacteria. The bacteria then produce the two protein chains separately. Afterward, scientists chemically join the chains together to form fully functional insulin that can be used as medicine.

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    Study Guide 2.3 Producing Human Growth Hormone Human growth hormone is also produced using bacteria. However, because bacteria do not normally make human proteins, scientists must use special techniques to help the bacteria correctly produce the hormone. This allows patients to receive safe and effective treatment. 2.4 Other Therapeutic Proteins Made by Biotechnology Biotechnology is also used to produce many other therapeutic proteins , including: • Tissue plasminogen activator (TPA) This protein helps dissolve blood clots. It is produced in genetically modified mammalian cells and is often used to treat heart attacks and strokes. • Interferon Interferon is an antiviral protein made in E. coli bacteria . It is used to treat certain cancers and some skin diseases. • Antisense molecules These are special RNA molecules that bind to mRNA , blocking protein production. By stopping the synthesis of harmful proteins, antisense molecules can help treat specific diseases. For example, they can prevent human cells from producing key components of the HIV virus after infection. 2.5 Biotechnology and Vaccines Vaccines are another important application of recombinant DNA technology. • The hepatitis B vaccine is made from viral proteins produced by yeast cells that carry recombinant DNA. This vaccine is very safe because it contains no actual virus particles . • Experimental AIDS vaccines are being developed using similar methods. One approach uses the vaccinia (cowpox) virus as a vector. This virus carries genes from several different viruses, with the goal of helping the immune system develop resistance to multiple diseases.

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    Study Guide 2.6 Creating Safer Vaccines Vaccines can also be made by removing disease - causing genes from a pathogen. The weakened organism cannot cause illness, but it still triggers the immune system to respond. This allows the body to build protection without the risk of serious infection. 3. Quiz Pharmaceutical Products 1. Question Which of the following statements about vaccines is FALSE ? Answer Choices • Some vaccines are produced by eliminating disease - inducing genes from a pathogen, rendering it harmless. • Vaccines are harmful, and the dangers outweigh the benefits. • Vaccines can be produced by using a virus as a vector. Correct Answer Vaccines are harmful, and the dangers outweigh the benefits. Why This Is Correct This statement is false because extensive scientific research shows that vaccines are safe and highly beneficial . They protect individuals and communities from serious, sometimes deadly diseases. While vaccines may have mild side effects, their benefits in preventing illness, disability, and death far outweigh any risks . The other statements are true : • Some vaccines are made by removing or disabling harmful genes in a pathogen so it cannot cause disease. • Some vaccines use harmless viruses as vectors to deliver genetic material that triggers an immune response.

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    Study Guide 4. Diagnostic Testing Recombinant DNA technology and biotechnology have completely changed the way doctors and scientists detect diseases . Today, many genetic disorders and infections can be identified early and accurately by examining a person’s DNA. 4.1 DNA Probes: The Basic Tool The most important tool in DNA testing is the DNA probe . A DNA probe is a small, single - stranded piece of DNA designed to find a matching (complementary) DNA sequence in a much larger DNA sample. Here’s how it works: • The probe searches for a specific DNA sequence • When it finds and binds to its matching DNA, it gives off a signal • This signal, similar to that produced by a radioactive marker, shows that the target DNA is present This makes DNA probes very useful for detecting specific genes or genetic changes. 4.2 Why PCR Is Needed For DNA probes to work well, scientists need a large amount of the target DNA . Often, the sample contains only a tiny amount, which is not enough to detect easily. To solve this problem, scientists use the polymerase chain reaction (PCR) . 4.3 Polymerase Chain Reaction (PCR): Making Millions of Copies PCR is a powerful method used to make many copies of a specific DNA segment in a short time. In a highly automated machine: • The target DNA is mixed with enzymes, nucleotides, and primer DNA • The enzymes repeatedly copy the target DNA

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    Study Guide • Each cycle doubles the amount of DNA Because this process grows exponentially, billions of copies of DNA can be produced in just a few hours, starting from only a few original molecules. 4.4 Detecting Diseases Using DNA Probes and PCR By combining DNA probes with PCR, scientists can detect many serious diseases with great accuracy. These techniques are used to identify: • HIV , providing a direct test for the virus itself This test is often preferred over antibody tests because it detects the virus directly. • Lyme disease • Genetic disorders , including: ○ Cystic fibrosis – a respiratory disease where thick mucus blocks airways, making breathing difficult ○ Muscular dystrophy – a nervous system disorder that causes muscle weakness due to nerve damage ○ Huntington’s disease – a nervous system disease marked by uncontrolled movements and nerve degeneration ○ Fragile X syndrome – a disorder of the X chromosome associated with intellectual disability 4.5 RFLPs: Markers Linked to Disease Genes Scientists often look for specific DNA segments called restriction fragment length polymorphisms (RFLPs) . • RFLPs are sections of DNA that do not seem to have a direct function • They are located near genes associated with diseases • By finding these RFLPs, scientists can locate the nearby disease - causing gene In this way, RFLPs act like signposts , helping researchers track down harmful genes.

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    Study Guide 4.6 Detecting Microorganisms in the Environment DNA probes are not only used in human medicine. They are also valuable for: • Detecting microorganisms in the environment • Identifying viral and bacterial pathogens This helps in disease control, environmental monitoring, and public health protection. 5. Quiz Diagnostic Testing 1. Question What is the purpose of the polymerase chain reaction (PCR)? Answer Choices • gene amplification • gene expression • gene recombination Correct Answer gene amplification Why This Is Correct The polymerase chain reaction (PCR) is a laboratory technique used to make many copies of a specific DNA segment . This process is called gene amplification . PCR allows scientists to start with a very small amount of DNA and produce millions of copies in a short time. This is essential for tasks such as DNA analysis, medical testing, forensic science, and genetic research. The other options are incorrect because: • Gene expression refers to using DNA to make proteins, not copying DNA. • Gene recombination involves rearranging or combining DNA segments, not amplifying them.

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    Study Guide 2. Question Fill in the blank: Using ________ and PCR, scientists are now able to detect the DNA associated with HIV. Answer Choices • DNA probes • plasmids • vectors Correct Answer DNA probes Why This Is Correct DNA probes are short, labeled pieces of DNA that bind specifically to a complementary DNA sequence. When used together with PCR , which amplifies DNA, DNA probes make it possible to identify and detect specific DNA sequences , such as those associated with HIV. The other options are incorrect because: • Plasmids are circular DNA molecules used mainly to transfer genes in genetic engineering. • Vectors are carriers (like plasmids or viruses) used to deliver DNA into cells, not to detect DNA. 6. Gene Therapy: Fixing Problems at the Genetic Level Gene therapy is a medical technique that uses recombinant DNA technology to treat diseases caused by faulty genes. The basic idea is simple: cells are taken from a patient, new genes are added , and the corrected cells are put back into the patient’s body. These added genes contain instructions for making proteins the patient’s body cannot produce properly .

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    Study Guide 6.1 Why Gene Therapy Does Not Affect Future Generations Gene therapy uses nonreproductive (somatic) cells , not egg or sperm cells. Because of this, the inserted genes: • Help only the treated patient • Are not passed on to future generations This makes gene therapy safer and more controlled. 6.2 A Successful Early Example: ADA Deficiency One of the first successful uses of gene therapy occurred in the early 1990s . It treated children who lacked an important enzyme called adenosine deaminase (ADA) . Here’s how the treatment worked: 1. Lymphocytes , a type of blood cell, were removed from the children’s bone marrow. 2. Scientists used viruses as vectors to insert normal ADA genes into these cells. 3. The genetically altered cells were then reinfused into the children’s bodies . 4. Once inside the body, the modified cells began producing ADA normally. As a result, the enzyme deficiency was corrected, and the disease was successfully treated. 6.3 Who Can Benefit from Gene Therapy? Scientists have identified over 4,000 disorders caused by defects in a single gene . Patients with these conditions may be good candidates for gene therapy, especially when traditional treatments are limited or ineffective. 6. 4 Safety and Ethical Oversight Because gene therapy directly changes genetic material, it is carefully regulated. Today, a strict, multilayered review system is in place to protect patients. Before any gene therapy experiment is approved:

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