Mutations!!!

1. Mutations!!!

2. Don’t forget……………… What nitrogen base pairs with Adenine? What nitrogen base pairs with Guanine? What is the name given for every set of three nitrogen bases on the DNA? What does one codon code for? When amino acids bond together, what do they form?

3. Gene Mutations • Mutations are changes in genetic material or DNA, and they can occur • during DNA replication • One in every billion base pairs is mutated • The average person has 6 mutations in each cell • Mutations are a major source of variation in a population and can help • organisms evolve (change over time) • Mutations in gametes are passed on to offspring • Mutations in body cells only affect the organism in which they • occur and are not passed on to offspring

4. ? If we have that many mutations and the some can be harmful, why don’t we look weird? Mutations are not always seen. Every part of your DNA doesn’t make a protein or trait. Remember this is called “junk DNA”.

5. Mutation: damage to genetic material A mutation to genetic material is usually not beneficial. Mutagens are things that cause mutations, they include: 1. High Temperatures 2. Toxic Chemicals (pesticides, etc) 3. Radiation (nuclear and solar) Many common place items are capable of causing mutations: microwave, fruit from the store, radar, cellular phones….

6. Somatic vs Germ Mutations • Some people may have mutations in their skin cells or hair. Such mutations are termed Somatic. • Germ mutations occur only in the sex cells. These mutations are more threatening because they can be passed to offspring (forever).

7. Meiosis is a prime time for mutations to occur. The germ mutations that occur during meiosis could be passed on during fertilization

8. Mutations affect protein synthesis Transcription: Mutated DNA will produce faulty mRNA leading to the production of a bad protein.

9. Types of mutations pages 307-308 Chromosomal: affecting whole or a part of a chromosome Gene: changes to the bases in the DNA of one gene

10. Gene Mutations • Change in the nucleotide sequence of a gene • May only involve a single nucleotide • May be due to copying errors, chemicals, viruses, etc.

11. } Also called Frameshift Mutations Types of Gene Mutations Point Mutation - involve changes in one or more nucleotides in DNA There are three types: • Substitution 2. Deletion 3. Insertion

12. Types of Point Mutations: Substitution Insertion Deletion

13. Substitution -one base is changed to another. • Usually affects a single amino acid in a protein or it may cause • no change in the amino acid • Has the least harmful affect An example of substitution mutations is sickle cell anemia. One amino acid changes in the hemoglobin, but the hemoglobin still functions in the RBC, just not as well.

14. Frameshift Mutations – changes that cause every codon that follows the mutation to shift position • A base is inserted or removed from DNA sequence • Insertion and deletion mutations have the most effect on an • organism because they affect many amino acids on the protein, • not just one. Huntington’s Disease is caused by an insertion mutation. People with this disorder have involuntary movement and loss of motor control. They eventually have memory loss. The disease is terminal and similar to Parkinson’s Disease, another motor loss syndrome.

15. “B” you’re out of here! Chromosomal Mutations • Mutations that change the number or structure of chromosomes Original Chromosome Deletion (B is deleted) Original Chromosome Duplication (Extra B is added) Inversion (D & C exchange positions) Original Chromosome Translocation

16. Chromosomal Mutations • Deletions – all or part of a chromosome is lost or removed • Duplications – produce extra copies of parts of the chromosome • Inversions – reverse direction of parts of the chromosomes • Translocations – occur when part of one chromosome breaks off and attaches to another chromosome • Nondisjunctions – occurs when chromosomes do not separate during meiosis

17. Chromosome Mutations Inversion

19. Are mutation important? How and why? • Most of the time mutations (neutral) go without ever being detected • Harmful mutations disrupt normal biological activities Examples: Diabetes. Cancer, and Trisomy 21 (Down Syndrome) Some statistics claim that as many as 1 in 700 embryos are Trisomy 21.  • Helpful mutations may produce proteins with new or altered activities that can be useful to organisms

20. Cancer – uncontrolled cell growth in multicellular organisms; cells divide continually and destroy healthy tissue – pages 252; 962; 1052-1054 Tumors – mass of tissue that grows and divides uncontrollably benign tumors (noncancerous) do not spread malignant tumors (cancerous) spread; invade and destroy surrounding tissue Liver CancerCancerous cells under attack www.cheerzhangover.com/horrors.htm www.zellerx.com/pages/nkcells.html

21. Causes of Cancer • Smoking • Defects in genes that regulate cell growth and cell division • Viruses can cause defect in genes or spontaneous mutations in DNA • Carcinogens- chemicals which can trigger DNA mutations (X-rays, forms of radiation, etc.)

22. Ways to Treat Cancer • Prevention is best treatment – healthy diet, avoid smoking, protect against sun and radiation, etc. • Early detection • Chemotherapy • Radiation treatment • Gene and molecular treatment