Experiment 5 The Importance of Cell Cycle Control Some environmental factors can cause genetic mutations which result in a lack of proper cell cycle control When this happens the possibility for uncontrolled cell growth occurs In some instances uncontrolled growth can lead to tumors which are often associated with cancer or other biological diseases In this experiment you will review some of the karyotypic differences which can be observed when comparing normal controlled cell growth and abnormal uncontrolled cell growth A karyotype is an image of the complete set of diploid chromosomes in a single cell Materials Internet Access Computer Access You must provide Procedure 1 Begin by constructing a hypothesis to explain what differences you might observe when comparing the karyotypes of human cells which experience normal cell cycle control versus cancerous cells which experience abnormal or a lack of cell cycle control Record your hypothesis in Post Lab Question 1 Note Be sure to include what you expect to observe and why you think you will observe these features Think about what you know about cancerous cell growth to help construct this information 2 Go online to find some images of abnormal karyotypes and normal karyotypes The best results will come from search terms such as abnormal karyotype HeLa cells normal karyotype abnormal chromosomes etc Be sure to use dependable resources which have been peer reviewed 2013 eScience Labs LLC All Rights Reserved 3 Identify at least five abnormalities in the abnormal images and list them in the Data section at the end of this experiment Do these abnormalities agree with your original hypothesis Hint It may be helpful to count the number of chromosomes count the number of pairs compare the sizes of homologous chromosomes look for any missing or additional genetic markers flags etc Data 1 Extra Sets of Chromosomes 2 Circles and Rings form 3 Entire chromosomes moved to another chromosome 4 Chromosome pairs are missing 5 Chromosomes turned upside down Post Lab Questions 1 Record your hypothesis from Step 1 in the Procedure section here The abnormal karyotypes will have more cells than those of normal karyotypes 2 What do your results indicate about cell cycle control My results show that it can create more chromosomes or not enough It can also cause the chromosomes to stick to each other It does not always cause more chromosomes It could also cause other abnormalities 2013 eScience Labs LLC All Rights Reserved 3 Suppose a person developed a mutation in a somatic cell which diminishes the performance of the body s natural cell cycle control proteins This mutation resulted in cancer yet but was effectively treated with a cocktail of cancer fighting techniques Is it possible for this person s future children to inherit this cancer causing mutation Be specific when you explain why or why not There would be a 50 possibility that the child would inherit this mutation It would also be possible in future generations but the odds of getting it will be higher This will also depend on the mutation The mutation can be a recessive trait or dominant trait depending on the genetic code 4 Why do cells which lack cell cycle control exhibit karyotypes which look physically different than cells with normal cell cycle This is caused by the crossing over of chromosomes 5 What are HeLa cells Why are HeLa cells appropriate for this experiment It s a line or population of cells taken from a person and used in research They are used here for studying the effects of diseases or developing medication 6 Research the function of the protein called p53 What does this function do Explain how it can affect cell cycle control This p53 protein is a protein that regulates the cell cycle and functions as a tumor suppressor It can help regulate the cell cycle and can help suppress cancer 7 What is the Philadelphia chromosome How is this chromosome related to cancer Identify how this chromosome appears physically different on a karyotype than it appears on a karyotype of normal chromosomes It is a chromosome that causes leukemia It is a short chromosome 22 that is involved in translocation with chromosome 9 It takes place in a bone marrow cell and through the process of clonal expansion it produces many cells from this mutant cell which causes leukemia It appears shorter on an abnormal karyotype 2013 eScience Labs LLC All Rights Reserved