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Understanding DNA Mutations and Their Effects

Learn about the different types of DNA mutations, their causes, and their effects on genes. Explore point mutations, frame-shift mutations, and chromosomal mutations, and understand the advantages and disadvantages of these changes.

garyschiller
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Understanding DNA Mutations and Their Effects

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  1. DNA Mutations

  2. Often times, parts of DNA will have a base (or more) missing, added, or incorrect Can be caused by: errors in replication, transcription, cell division, or by external agents (like radiation) What is a gene mutation?

  3. A mutation is any change in the Nucleic Acid (DNA/RNA) sequence. Any agent that can cause a mutation is a mutagen. Any mutagen that causes cancer is a carcinogen Any mutagen that causes birth defects is a teratogen What is a gene mutation?

  4. Mutagens • Any agent that can cause a mutation • These are caused by factors in the environment such as: • Radiation (x-rays, UV, nuclear) • Chemicals • Extremely high temperatures • Biological agents such as HPV

  5. Mutations occurs at a frequency of about 1 in every 1 billion base pairs Everybody has about 6 mutations in each cell in their body! How common are mutations?

  6. Point Mutations Substitution Insertion w/ frameshift Deletion w/ frameshift Chromosomal Mutations Deletion (a piece missing) Duplication (a piece copied) Inversion (a piece flipped) Translocation (a piece moved to another location) The most common types of mutations are:

  7. 1. Substitution – a different base is substituted for the original Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC DNA (Gene) Mutation What has happened in this mutation?

  8. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC DNA (Gene) Mutation *Adenine was accidentally replaced with thymine *What is this mutation called?

  9. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TGC - TTC Substitution What will happen to the amino acids?

  10. Original DNA- ATC would code for : STOP • Mutated DNA of TTC would code for: Lysine

  11. 2. Insertion with Frameshift - produce extra copies of parts of a chromosome. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C DNA (Gene) Mutation What has happened in this mutation?

  12. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C DNA (Gene) Mutations *Adenine was inserted, causing the remaining DNA to shift to the right. *What is this mutation called?

  13. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TAG – CAT - C Insertion with Frameshift What will happen to the amino acids?

  14. DNA (Gene) Mutation 3. Deletion - loss of all or part of a chromosome. Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC What has happened in this mutation?

  15. DNA (Gene) Mutation Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC *Guanine was removed,causing the remaining DNA to shift to the left *What is this mutation called?

  16. Deletion w/ Frameshift Normal DNA: CGA – TGC – ATC Mutated DNA: CGA – TCA- TC What will happen to the amino acids?

  17. What happens if you accidently skip an answer on a scantron sheet?

  18. Substitution or Point Mutation • THE DOG BIT THE CAR • THE LOG BIT THE CAR • THE DOG BIT THE CAT • THE DOG HIT THE CAR • THE HOG BIT THE CAR • THE FOG BIT THE CAR

  19. Insertion Mutation • THE DOG BIT THE CAR • THH EDO GBI TTH ECA R

  20. Deletion Mutation • THE DOG BIT THE CAR • THE OGB ITT HEC AR

  21. Gene mutations • 4. Point mutations • Change one nucleotide or just a few nucleotides in a gene • Examples: sickle cell anemia & cystic fibrosis • Cancer, color blindness • 5. Frame-shift mutations • The reading pattern is displaced and “shifts” into new positions • Examples: duchenne Muscular Dystrophy

  22. Frame shift mutations • The cat and the rat ran far. • The ca and the rat ran far. • The caa ndt her atr anf ar. t

  23. Chromosomal mutations • 6. Inversion = reverse the direction of parts of a chromosome. • 7. Translocation = occurs when part of one chromosome breaks off and attaches to another different chromosome.

  24. Mutations: Changes in DNA Advantages: Disadvantages: New, stronger genes can be passed on to offspring • Abnormal, even lethal genes can be passed on to offspring

  25. Are they harmful? • b. Silent mutations – changes the nucleotide sequence by has no effect on the synthesized protein • c. Non-sense mutations – creates a protein that is not usable. HARMFUL

  26. Construct the Chart: • Cut out chromosomes to compete the chart on Chromosomal Mutations

  27. Chromosomal Mutations

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