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Biology Producing New Cells Learning Intentions 1. Why do cells need to make new copies of themselves? 2. What is found inside the nucleus? 3. What are the stages in the process of cell division? 1. Why do cells divide? Cells have to divide so organisms can:- 1. Grow 2. Repair cells (e.g.broken bones, wounds) 2. Cells Dividing 1. 2. 3. 4. Parent Cell Nucleus (containing genetic information) divides into 2 Cytoplasm divides into 2 Two new cells (identical to the parent cell) are formed Why do you think it is so important that the nucleus divides properly? 3. What is inside the nucleus? The nucleus contains thread-like structures called chromosomes Chromosomes are made up of 2 chromatids joined together. Chromosomes contain important genetic information. 4. Chromosome Complement The characteristic number of chromosomes that certain organisms should have is called the “Chromosome Complement” Human Dog 5. Diploid and Haploid Cells Human body cells have 46 chromosomes (2 sets of chromosomes) and are called Diploid Cells Human gametes (sperm/eggs) have 23 chromsomes (1 set of chromosomes) and are called Haploid Cells Human Body Cells 46 chromosomes 2 sets of chromosomes in each cell Diploid (2 sets) Human Gametes (sex cells) 23 chromosomes 1 set of chromosomes Haploid (1 set) 6. Mitosis Mitosis is the process of Cell Division The stages in Mitosis are:Stage 1 Parent Cell chromosomes are copied Stage 2 Chromosomes become visible Stage 3 Chromosomes line up at equator Stage 4 Chromatids are pulled apart to either pole by spindle fibres Stage 5 Parent cell divides to produce 2 new cells identical to parent cell Mitosis ensures that the new cells contain the same number and type of chromosomes (the chromosome complement) so the new cells can develop and function properly mitosis glow video You Tube Mitosis animation Bitesize animation Its Playdoh Time!! 7. Uncontrolled Cell Division Normal cell division (mitosis) is carefully controlled so new cells develop properly. Abnormal uncontrolled cell division (mitosis) can lead to different types of cancers what is cancer -glow video Stem Cells Learning Intentions 4. State the role of stem cells 5. State the role of meristems 8a) Stem Cells Stem cells are cells that have the potential to develop into any type of cell Video Clip - “A Stem Cell Story” at www.eurostemcell.org/films 8 b) Stem Cells have 2 roles Stem cells are different from other cells of the body because stem cells can: 1. SELF-RENEW (Make copies of themselves) AND 2. Differentiate (Make other types of cells) 2c) Stem Cell Facts 1. Stem cells are found in all plants and animals 2. Stem cells are produced by cell division 3. Stem cells have the potential to develop into any type of cell 4. Stem Cells are involved in growth and repair and can be used to grow many different types of cells, tissues, organs 5. In animals cell division occurs all over the body 6. In plants cell division only occurs in structures called meristems Stem Cell video clip (3:13) 8d) Stem Cells & Medical Treatments Activity Cards - EuroStem 8e) Different Types of Stem Cells There are 2 different types of STEM CELLS:1. Tissue Stem Cells (also called Adult Stem Cells) 2. Embryonic Stem Cells 8f) Where do we find Embryonic Stem Cells? 8g) Where do we find Tissue Stem Cells? Therapeutic Cells Clip 3:26 8h) Stem Cells: A controversial topic A controversial topic, is a topic that people will disagree about. Embryonic Stem Cells cause the most arguments and disagreements. Arguments FOR the use of Embryonic Stem Cells • Embryonic Stem Cells can develop into ANY type of cell so they are the most useful type of stem cell • Stem cells can be used to make cells you need, test drugs, understand diseases, develop new medicines, • Embryonic Stem Cells can be used to save the lives • The embryos used for Stem Cell Research are from embryos that are no longer needed for IVF Treatments for couples trying to have babies. Once fertilisation is successful, there are spare embryos, and the couple have 3 choices:1) Destroy the embryos 2) Donate embryos to another couple 3) Donate embryos to scientific research on STEM CELLS Arguments AGAINST the use of Embryonic Stem Cells • Embryos could eventually become babies, so some people believe that scientists are destroying a human life when they use these embryos for research. • Needs much more research before we understand full implications of this procedure. 9a) Mitosis & Biotechnology CELL CULTURES Cell Production by Cell Cultures In Biotechnology, humans can artificially produce new cells by creating cell cultures. Cell cultures are when cells are taken out of a living organism and grown in a Lab using aseptic techniques. The cells can be used for research, Drugs and Tissue therapy to help patients (e.g. Growing new skin cells for burns sufferers or growing new strains of carrots that can survive in areas of drought) Cells that can develop into other types of cells are called STEM CELLS 9b) Mitosis & Biotechnology CELL CULTURES Aseptic Techniques Aseptic techniques are techniques used to help avoid contamination 9c) Mitosis & Biotechnology CELL CULTURES Cell Production by Cell Cultures In order to produce new cells by cell culture, there must be:- Aseptic techniques used An appropriate growth medium Control of factors e.g. temperature, pH Cell cultures are used for many applications e.g. skin grafts, medical research, disease resistant plants Practical – Cauliflower Cloning 10. Meristems 1. Cell division in plants only occurs in meristems 2. Stem cells found in the meristems have the potential to develop into any type of plant cell e.g. xylem, phloem, palisade mesophyll cells 3. Apical meristems are found at the root and shoot tips. Apical meristems increase the length of a plant. 4. Lateral meristems are made of cambium which is found in the vascular bundles between the xylem and phloem Lateral meristems increase in the girth (thickness) of the plant; this process leads to the formation of annual rings.