ENKEL Biologi - Genetik PDF

# ENKEL Biologi 7-9 ~ del 3 ## Genetik - Genetik is another word for heredity and deals with how our genes are passed down. - With the help of genetics, we can understand better how characteristics are passed down from parents to children. ## Chromosomes - A human being is made up of billions of c...

# ENKEL Biologi 7-9 ~ del 3 ## Genetik - Genetik is another word for heredity and deals with how our genes are passed down. - With the help of genetics, we can understand better how characteristics are passed down from parents to children. ## Chromosomes - A human being is made up of billions of cells. - In every cell, there is a nucleus. - It is in the cell nucleus where genes exist. - They are contained within chromosomes. - Chromosomes were discovered in the 19th century with the help of a microscope after dyeing the cell nucleus. - Chromosomes means colored body. - It took a long time before scientists understood that genes are located within chromosomes. ## DNA - Each chromosome contains a giant molecule, called DNA. - The DNA molecule itself contains genes. - DNA stands for Deoxyribo-Nucleic-Acid. ## Generating a new cell - When a cell is about to divide, chromosomes bunch up and are visible via a microscope - After this, each chromosome copies itself and splits up, resulting in two copies. - The copies end up in separate cells when the cell divides. - This way, the genetic information is copied and lives on. - There are 46 chromosomes in a cell. - They exist in 23 pairs. - You get 23 chromosomes from your mother and 23 from your father. ## The genetic Code - A gene is a specific part of the DNA molecule - Each gene contains instructions on how a cell should build a specific protein. - Some genes are short and only contain a few hundred base pairs. - Other genes are longer and can contain hundreds of thousands of base pairs. - A human being has around 22,000 different genes - It is the genes that give us our characteristics, but not all genes are active in all cells. ## The genes are passed down from parents to children - Parents give their offspring genes through sperm cells (male) and egg cells (female) - This process is called sexual reproduction. - A human being has 46 chromosomes. - Half of these come from your mother and half from your father. - Sex cells only carry 23 chromosomes. - When they merge, a fertilized egg cell is created which has 46 chromosomes. ## Sex Cells - To create sex cells, a special kind of cell division is needed. - It's called reduction division or meiosis. - Sex cells have half the amount of chromosomes (23) - Reduction happens in the testes (male) and ovaries (female), where sperm cells and egg cells are produced - When a sperm cell fertilizes, an egg cell becomes either a boy or a girl. - One chromosome pair defines the sex of a person. - One chromosome is called X-chromosome and the other Y-chromosome. - A female always has two X-chromosomes (XX), while a male has one X-chromosome and one Y-chromosome (XY). - All female egg cells contain an X-chromosome - Male sperm cells contain either X-chromosome or Y-chromosome, depending on the sperm cell - If an egg cell is fertilized by an X-chromosome, it will become a girl. - If an egg cell is fertilized by a Y-chromosome, it will become a boy. ## Natural cloning and artificial cloning - Many animals and plants can reproduce without sex cells. - Single-cell organisms can clone themselves. - Plants can grow roots, which results in clones. - This method is called cloning. - Clones are multiple living beings that have the same DNA as the mother cell. - Humans can also clone themselves in the form of twins. - Identical twins have exactly the same DNA - Scientists have also successfully cloned individual animals, such as cows and pigs for better milk production and quality meat, - Scientists use different methods for cloning. - You can clone a fertilized egg cell by separating it. - This way, you will get multiple eggs (4) that you can implant in different mother mammals. - These mother mammals will then birth four new animals with the same DNA as the initial cloned egg cell. ## Intermediate inheritance - When you cross two different flowers that have different colours, the resulting flower might have a colour that is a mix of two original colours. - For example, if you mix two flowers that have red and white colours, the resulting flower will be pink. - This is called intermediate inheritance. ## Gregor Mendel - Gregor Mendel was a monk and scientist who lived in the 19th century - In his garden, he studied peas until he discovered, that factors influence certain traits - These factors determine the traits in children. - Mendel did not know the name of the factors, but he was familiar with their dominant and recessive traits. - He is considered the father of genetics. ## Mutations - Sometimes, a gene can be modified. - This usually happens when a cell divides. - Usually, the cell fixes itself. - But sometimes the modification persists. - This modification is called a mutation. - Most mutations do not influence things. - Some mutations are good for the evolution of a species. - Some mutations are bad for the species and can lead to diseases. ## Inherited illness - Sometimes, a gene is damaged, which can result in illnesses. - Usually, the second gene in the chromosome is not damaged. - Therefore, these illnesses might not be visible. - But there are cases where both parents have the recessive trait for the illness, then the child might inherit the illness ## Chromosomal changes - Changes in chromosomes during cell division, can cause diseases. - Sometimes, a cell does not divide as it should. - This causes 47 chromosomes in a cell instead of 46. - This situation is called Downs syndrome. - People with this syndrome learn slower, have vision and hearing problems, and require more support than others. ## Gene engineering - Gene engineering helps us change genes and use genes in different ways. - We can extract DNA from one species and insert it into another. ### Genetically modified organisms (GMOs) - GMO refers to organisms whose DNA has been modified using gene engineering. - Gene engineering can be used to make agricultural products better, such as soybeans and maize. - For example, we can implant genes in maize that produce its own anti-insect poison, which means the products last longer ## Gene therapy - Gene therapy can help with genetic diseases - A malfunctioning gene is replaced with a healthy one. - This procedure is best for people who lack certain white blood cells. ## DNA analysis - With a blood sample or hair sample, scientists can identify a person. - It can also be helpful for tracing back family histories, and determining if a person is predisposed to a specific disease. ## Potential risks of gene engineering - It can be dangerous to modify genes, in particular when it comes to agriculture. - For example, plants and animals that have been modified genetically could be more resistant to insects or diseases. - This resistance could make genetically modified organisms more competitive in nature and potentially cause problems for naturally growing organisms and ecosystems in a broader sense. - For instance, if a genetically modified plant has a resistant gene to a common disease, it may outgrow and outcompete natural plants in that area. ## Biotechnology - This involves the use of cells and organisms to develop and produce products. - Biotechnology has been around for a long time. - Ancient farmers already used biotechnology for various purposes including brewing, making wine and bread. ## Gene engineering - Gene engineering is a modern form of biotechnology, - It involves changing an organism's genes. - Gene engineering can be used for various purposes, for example, changing a gene in a bacterium to produce insulin, which is used to treat diabetes. - In gene engineering, DNA can be cut and transferred. - This procedure requires certain enzymes, which act like scissors. - They cut the DNA fragment that we need. - This DNA fragment can be inserted into the DNA of another organism, such as a bacterium. - This is called a DNA hybrid. - Genetically modified bacteria can produce insulin. - This insulin can be given to people with diabetes. - You can also produce growth hormones for children who lack these hormones. ## Summary - Understanding genetics can help us understand how traits are passed down from parents to children. - It can also help us understand the potential risks of gene engineering and its enormous potential for improving human health and agriculture. - We need to use this technology responsibly, while being aware of its potential impact on the environment, and ensure that all people have a benefit, not only a small group of people.