Presentation on theme: "Cancer & Mutations Powerpoint SB2. Students will analyze how biological traits are passed on to successive generations. d. Describe the relationships between."— Presentation transcript:
Cancer & Mutations Powerpoint SB2. Students will analyze how biological traits are passed on to successive generations. d. Describe the relationships between changes in DNA and potential appearance of new traits including Alterations during replication. Insertions Deletions Substitutions Mutagenic factors that can alter DNA. High energy radiation (x-rays and ultraviolet) Chemical
Kinds of cancer Carcinomas – grow in the skin and he tissues that line the organs of the body –Ex. lung and breast cancer Sarcomas – grow in bone and muscle tissue Lymphomas – solid tumors that grow in the tissues that form blood cells –Ex. leukemia, the uncontrolled production of white blood cells Cancer - Uncontrolled cell growth *Cells only grow during the correct conditions *Limited by space, nutrients, chemicals, etc. What is Cancer?
Tumor Tumor - mass of cell due to uncontrolled cell growth –Benign - an abnormal, non-threatening cell mass –Malignant - uncontrolled cell mass that continually divides and multiplies –Metastasis - spread of cancer cells beyond original site
Cancer Cancer cells, unlike normal cells, continually grow even when the region is over crowded. –The cell does not recognize the message to stop dividing. Normal cells will not go through cell division unless they are attached to neighboring cells. –The cancer cells continue to grow and this leads to the spread of the problem throughout the body, also called metastasis.
What causes cancer? Growth factors - proteins that ensure the events of the cell cycle progress in proper order. Ex Cyclins and CDKs Mutations in these proteins result in uncontrolled cell growth.
Cancer causes Carcinogens - any substance that increases the risk of cancer –Ex. Tobacco, asbestos, and radiation such as X-ray, and UV light from sun.
Genes related to cancer Oncogenes – gene that causes cancer or other uncontrolled cell proliferation Proto-Oncogenes – gene that codes for proteins involved in the cell cycle Tumor-suppressor genes – code for proteins that prevent the uncontrolled rate of cell division
Discussion Can Cancer Occur Organisms other than humans? A.Yes B.No
What is a mutation? Mutation – a change in the DNA of an organism Germ-line mutation – occur in gametes of organism –Passed on to offspring, do not affect the organism Somatic mutation – mutations in the organisms body –Affect the organism, but not passed on to offspring –Ex. Skin cancer, leukemia, any cancer
What causes mutations? Mutagens – agent that causes mutations to occur within a cell. –Ex. Ionizing radiation, Base analogs, Intercalating agents, and Bromine
Types of mutations Chromosome mutations – changes in the structure of a chromosome or loss of an entire chromosome. –Deletion – loss of piece of DNA due to chromosomal breakage –Duplication – Chromosomes steal part of homologs and have both alleles for each gene involved –Inversion – piece of DNA breaks off and reattaches itself in opposite direction –Translocation – chromosome breaks off and reattaches to a non-homologous chromosome –Nondisjunction – chromosome does not properly separate from its homolog during meiosis
Nondisjunction Results in gametes receiving to many or too few chromosomes Ex. Down Syndrome = trisomy of chromosome 21
What kind of chromosomal mutation is this? Original chromosome A.Duplication B.Translocation C.Inversion D.Deletion
What kind of chromosomal mutation is this? Original chromosome A.Duplication B.Translocation C.Inversion D. Deletion
Gene Mutations May involve a large section of DNA or a single nucleotide within a codon Point mutation – the substitution or change of a single nucleotide Insertion or Deletion – one nucleotide is removed from or added to a sequence Frame shift mutation – occurs when codons are incorrectly grouped
Point Mutation Can result in –No effect - the protein structure is not changed –Missense – one amino acid is replaced by another –Nonsense – prematurely stop codon in amino acid sequence
Point mutation Ex. Sickle cell anemia –mutation in a single nucleotide that causes the malformation of the hemoglobin molecule which carries oxygen to our cells
Insertion and Deletion The removal or addition of a nucleotide base to a sequence usually results in a frameshift mutation.
Using the genetic code provided, which chain of amino acids corresponds to this mRNA sequence? UCAAUGGUCUGA A.Glu, Tyr, Met, Arg B.Ser, Val, Arg, Stop C.Ser, Met, Val, Stop D.Val, Iso, Asp, Stop
What if the first G was changed to a C, what would the new amino acid chain be? UCAAUGGUCUGA A.Glu, Tyr, Met, Arg B.Ser, Leu, Arg, Stop C.Val, Ile, Ser, Stop D.Ser, Iso, Val, Stop
What affect does this mutation have on the function of the protein? Proteins are folded in a specific fashion according to the amino acid sequence it contains. This would cause the function of the protein to be severely reduced or not functional at all.
Mutations lead to Evolution Mutations are not always bad, they often provide variations on proteins and sometimes these are advantageous to us. Survival of the fittest and Natural selection.
How can one tell the history of hereditary traits in his or her family? Pedigree – diagram of genetic history of an individual showing how traits are inherited over several generations
Pedigrees Genetic disorders – diseases or debilitating conditions that have a genetic basis –Carriers – individuals with one copy of a recessive autosomal allele; do not usually express the disorder but can pass on to offspring Dominant disordersRecessive disorders
Polydactyly Dominant trait that results in offspring with extra fingers or toes.
Hemophilia A sex-linked, recessive genetic disorder that affects the individuals ability to clot blood.