National 5 Biology Unit 1 Cell Biology Section

National 5 Biology Unit 1 – Cell Biology Section 3 Therapeutic use of Cells

Think, pair and share Start Timer 2 • What different kinds of cells are there? (hint there are 4) 1 • What does the word therapeutic mean? • Do you know any uses of cells outside of the body? 0

We will be learning… • State what genetic engineering is • Explain how genes can be altered by genetic engineering • Give examples of products by genetic engineering and their advantage to mankind • Investigate uses of genetic engineering e. g. • insulin production • factor VIII • human growth hormone • Explain that there are different types of stem cells and explain why they are important in the body • Discuss why and how stem cells are used by scientists • Research some medical uses of stem cells

Structure of a Typical Bacteria cell membrane cell wall plasmid (additional DNA) cytoplasm main DNA ring (single chromosome) • • flagellum for movement (not always present) The DNA in bacteria is not in a proper nucleus. Instead it consists of a main ring or coil of DNA. In addition to this, there are other smaller rings of DNA called plasmids. Plasmids are involved in bacterial reproduction.

What is Genetic Engineering? Genetic engineering is the process of altering the genetic code of a cell or organism. Using this process, it is possible to take a gene from one organism and put it into a different organism. https: //www. youtube. com/watch? v=j. Ahj. Pd 4 u. NFY

Why Would we Want to do this? So far, this technology has been used for a variety of purposes. • Making insulin to treat diabetes • Making human growth hormone • To make plants resistant to disease • Spider-goats • Glow-in-the-dark organisms

Genetic engineering is when pieces of chromosome (DNA/genes) are transferred from one organism to another Material is often transferred to bacteria as their DNA is loose in the cytoplasm, making it easy to modify. They also grow and replicate quickly. loose strand of main DNA plasmid – small ring of additional DNA A new gene can be inserted into the plasmid and the bacteria then produce the protein for which the gene codes.

The Steps Involved. . . 1. The required gene is located on the donor chromosome. 2. The gene is removed from the chromosome. 3. A plasmid is removed from a bacterium. 4. The plasmid is cut open. 5. The gene is inserted into the plasmid. 6. The genetically altered plasmid is inserted into a bacterium. The altered bacterium is propagated in optimum growing conditions to produce many identical cells that can be used as biochemical “factories”.

Human DNA with desired gene is located Cut out the gene with endonuclease enzyme Bacterial plasmid Cut open the plasmid with endonuclease Gene inserted into plasmid using ligase

Put the plasmid into a bacterial cell The bacterial cell will make (synthesis) the protein that the new gene codes for. Bacteria cell with desired gene in it

DNA Human DNA with desired gene is located Cut out the gene g n i r nee i g n E c i t e n Ge loose strand of main DNA Bacterial plasmid Cut open the plasmid Gene inserted into plasmid Put the plasmid into a bacterial cell plasmid – small ring of additional DNA

Steps in Genetic Engineering • Label the diagram in your notes • Write the steps below your diagram in your notes on page 3: • The desired gene is identified and removed from the chromosome by endonuclease. • The bacterial plasmid is cut open using endonuclease. • The desired gene is inserted into the plasmid using ligase. • The plasmid is inserted into the bacterial cell • The bacterial cell synthesises (makes) the protein coded for by the forgien gene.

Advantage of using Micro-Organisms e. g. Bacteria • Bacteria are commonly used because they can be grown quickly and easily, often at low cost. • Given suitable conditions, genetically modified (GM) bacteria multiply at a rapid rate and manufacture large quantitites of a useful product than can then be extracted, concentrated, purified and put to use.

Uses Genetic engineering has been used for a number of reasons by scientists including: • • • making medicines making plants resistant to disease glow-in-the-dark organisms and cells an enviropig the spider-goat. This website lists 12 examples of genetic engineering from around the world.

Insulin • What is insulin? It is a protein (hormone) that keeps the glucose levels in our bodies steady. It is produced in the pancreas • Some people need to take insulin every day of their lives. • What are these people suffering from? Diabetes • Diabetes is a condition where the person’s body is unable to control their blood sugar levels properly. • This is caused by their body failing to produce enough insulin.

Taking insulin • Most diabetics need to take insulin daily. • This is usually done by injection. • Some diabetics have an insulin pump fitted which automatically injects the right amount of insulin when their blood sugar level is too high. • As the human population is increasing, there are more and more people who are diabetic, so more and more insulin is needed. • It is possible to genetically engineer bacteria to get them to make insulin.

Making Insulin GM insulin has some advantages over insulin taken from pigs or cattle: 1. It is easier to create high quantities of insulin 2. It is less likely to cause an adverse reaction e. g. allergies 3. It overcomes ethical concerns from vegetarians and others Traditionally, in the days before genetic engineering, people with diabetes were treated with pig or beef insulin

GE in Medicine – Human Growth Hormone Human growth hormone is a protein made by the pituitary gland in the brain and is essential for normal growth and development. Human growth hormone can be made via genetic engineering and can be given to children who are not growing properly. Scientists have known about growth hormones since the 1920 s but only began using HGH to treat kids who were unusually short because of pituitary disorders in 1963. Use of the drug was fairly conservative, however, because it was in short supply, due to the fact that there was only one source of HGH—humans. Gathering the drug meant isolating it from the pituitary glands of animal cadavers,

Problems with HGH pre- GM Production • Production of the drug in this way continued for more than 20 years. That all came to a halt, however, with the horrifying discovery that some of the drug was contaminated, having been extracted from a cadaver infected with Creutzfeldt-Jakob disease (CJD). CJD is similar in effects to mad cow disease or accelerated Alzheimer's, causing rapid brain degeneration leading to death within a year of the first symptoms. There is no treatment and no test for CJD, which can lie dormant for decades after exposure before signs of infection appear. • Eventually, 26 people would die of CJD from contaminated HGH. The fact that there was no way to test for infection turned the lives of all of those who had been treated in the 1960 s and 1970 s into a terrifying waiting game.

Advantages to Genetically Engineered Human Growth Hormone 1. Bacteria can be grown in large fermenters e. g. large quantities can be made 2. No risk of CJD infections 3. Cheaper to make/unlimited supply

Too little Growth Hormone! Human growth hormone can be made via genetic engineering and can be given to children who are not growing properly

Too much Growth Hormone! • Before being banned in 1989, HGH was used by some sports-people to increase muscle size. • In adults, excessive growth hormone for a long period of time produces a condition known as acromegaly, in which patients have swelling of the hands and feet and altered facial features.

What is Haemophilia? • Haemophilia is an inherited condition that affects the blood's ability to clot. • Normally, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky. This makes the bleeding stop eventually. • However, in haemophilia, there aren't as many clotting factors as there should be in the blood. This means that someone with the condition bleeds for longer than usual. • The condition is passed to a child by one or both of their parents.

Factor VIII to treat Haemophilia GM blood clotting factor

Advantages and Disadvantages of Genetic Engineering Advantages Disadvantages Can transplant genes from one Inserted genes may have species to another e. g. organs as unexpected harmful effects replacements for human hearts and kidneys Produce food and crops that are bigger and grow faster, resistant to disease, can thrive in different environments, or can be customized based on the soil composition and availability of water in a location, world hunger could be minimized Herbicide resistant crops, can lead to the growth of weeds that are resistant to herbicide and the loss of weed species that are essential to animal food and shelter Potential to identify and replace Blending animal and human DNA mutant genes can have uncertain effects

Stem Cells • Involved in growth and repair of organisms • Stem cells are found in all multicellular animals • Stem cells are undifferentiated i. e they have no specific structure or function. • Produce specialised cells in animals. • Have the ability to become any type of cells.

Stem cells • They have the ability to renew themselves through mitotic division. • They are found throughout the organism. • There are two main types of mammalian stem cells • 1. embryonic stem cells 2. Adult stem cells

Types of Stem Cells • Embryonic stem cells • - derived from embryos that develop from eggs fertilised in a laboratory. • • Adult stem cells Found in body along side other differentiated cells Examples - bone marrow - blood vessels - skin - liver - heart • They are body’s built-in repair kits • Replace cells damaged by disease, injury and every day wear and tear

Adult Stem Cells • In adult tissue there are stem cells present also. They are found throughout the body. • In adults these cells act as a repair system i. e. this allows the replenishment of cells such as, blood, skin or intestinal tissues which are in constant need of replacement. • Used to replace any damaged tissue.

Source of stem cell Marrow in bones Skin Heart muscle Bladder Medical Use Treating leukaemia, a type of cancer caused by abnormal blood cells. Growing new layers of skin that can be used to treat burn victims. Repairing damaged heart muscle after a heart attack (still being tested at the moment) Building a new bladder in the laboratory for a patient whose bladder has been damaged by injury or disease.

Complete the following table • Unlimited supply • Can differentiate into any cell • Doesn’t mean that embryos are destroyed • Embryos have to be destroyed – ethical issue e. g. pro-life campaign • Limited supply • Can only differentiate into

Using stem cells in the treatment of leukemia (a form of cancer)

Dilemma! Vote with your feet! The following slides contain dilemmas associated with genetic engineering and stem cell research. Watch the video clip and then think about the dilemma shown on the slide. If you agree with the dilemma – go to the left side of the class. If you disagree with the dilemma – go to the right side of the class. If you don’t know stand in the middle.

Dilemma 1 Scientists believe they can come up with a cure for cancer. However their research requires using stem cells from human embryos. Should scientists be allowed to take an unborn child's life for research purposes? Dilemma 1 Therapeutic stem cells

Dilemma 2 Scientists have discovered the gene that cause a hereditary disease which leaves victims in pain throughout their short life. Genetic engineering means that parents can choose the genetic make up of their child before they are conceived. Should parents be allowed to have designer babies, so they can choose their genetic make up? Dilemma 2 Designer babies 1 Designer babies 2

Dilemma 3 Cloning intelligent scientists (like Einstein!) might lead to improved scientific research and make the other scientists work better (two heads are better than one? ). A cure for cancer may come sooner if this were the case. Should human cloning be allowed? Dilemma 3 Cloning The first human clone?

Dilemma 4 Carrie is 5 and has a medical condition which means that she cannot walk very well, is in pain and is so tired all the time that it is hard for her to attend school or lead a normal life. Carrie’s Mum and Dad know that a donation of bone marrow from a close relative could help her. Nobody in the family is a close enough match. They have decided to have another child by selecting an embryo which is a match for Carrie. Should ‘saviour siblings’ be allowed? Dilemma 4 Saviour siblings

Meet Maggie and Jean…. Who are you most likely to support? Jean can’t have children. She believes that some peoples fate is to adopt the children who are unwanted them withyears a loving home because deserves a loving. IVF. home. Maggie can’t and haveprovide children. After of no success she everyone is finally about undertake Jean hasn’t is a campaigner, devotes her life to believes campaigning abortion. Maggie consideredshe adoption because she thatagainst the bond with your child comes from the She believes children areand unwanted right tobaby. live so people who want children can adopt development in the womb, who birth bondinghave withthe a newborn them. Why? Jean is also against IVF as she believes that since it has become more advanced and more common, more people choose IVF over adoption because they prefer to have their “own” child, leading to a greater number of children needing adopted.

Success Criteria By ofwhat this genetic sectionengineering you should isbe able to: • Ithe canend state • I can explain how genes can be altered by genetic engineering • I can give examples of products by genetic engineering and their advantage to mankind • I can investigate uses of genetic engineering e. g. • insulin production • factor VIII • human growth hormone • I can explain that there are different types of stem cells and explain why they are important in the body • I can discuss why and how stem cells are used by scientists • I can research some medical uses of stem cells

Word Definition Plasmid A circular piece of DNA found inside a bacterial cell Bacteria A single celled organism which can be used in genetic engineering to make a product e. g. insulin Gene A long section of DNA which codes for a particular characteristic Insulin Protein made by the pancreas which controls blood sugar Genetic Engineering The process of altering an organisms genetic code. Human Growth Hormone A chemical made by the pituitary gland which controls growth and development particularly in children Clotting Factor VIII A blood clotting factor made through genetic engineering given to patients with haemophilia Haemophillia A blood disorder where patients lack factr VIII which is needed to clot blood Enzyme A biological catalyst which speeds up chemical reactions Stem Cell A cell that can give rise to more of the same cells and/or can differentiate into other cell types

Word Definition Diabetes A disease in which the body can’t produce or respond to the hormone insulin Cancer A disease caused by uncontrolled cell division Embryonic Stem cells from the inner mass of cells of a human embryo that can differentiate into any cells in the body Adult Tissue Stem Cells found throughout the body that can only differentiate into a limited number of cells.

Jobs slide • Research Scientist • Business development Manager • Geneticist • Genetic engineer