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To demonstrate understanding, after this lesson, you should be able to  define mutations  explain how mutations occur when – DNA Replication or Meiosis.

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Presentation on theme: "To demonstrate understanding, after this lesson, you should be able to  define mutations  explain how mutations occur when – DNA Replication or Meiosis."— Presentation transcript:

1 To demonstrate understanding, after this lesson, you should be able to  define mutations  explain how mutations occur when – DNA Replication or Meiosis how – radiation &mutagenic chemicals  recognize point (N-base) mutations (insertions, deletions and substitutions)  recognize chromosomal mutations (deletion, duplication, inversion, insertion, translocation)

2 I. Mutations  …are any change in the DNA of an organism.  May not have any affect or may cause a major deformation, illness.

3 I. Mutations  …are any change in the DNA of an organism.  May not have any affect or may cause a major deformation, illness.

4 I. Mutations I. Mutations Any change in DNA is a mutation. caused by mistakes during…  DNA replication of mitosis  Transcription  meiosis Also can be caused by environmental factors like… Also can be caused by environmental factors like…  Radiation  Carcinogens

5 Mutations in Reproductive (Sex) Cells VS. Body cells Mutations in Reproductive (Sex) Cells VS. Body cells -Mutations in sex cells a.k.a. gametes (sperm and egg cells) can be passed down to a person’s children, but might not affect the parent -Mutations in body cells cannot be passed on to your children, however, they can cause cancer or other problems

6 II. Cancer as a result of mutations in body cells: II. Cancer as a result of mutations in body cells:

7 II. Cancer as a result of mutations in body cells: Tongue cancer and lung cancer are often caused by changes in body cells as a result of smoking, so don’t smoke!!! Carcinogens- environmental/chemical factors that cause cancer

8 III. Gene Mutations  Point Mutation only 1 codon is affected only 1 codon is affected example: “substitution mutation” example: “substitution mutation” AUC GGA UCC  AUC CGA UCC THE FAT CAT WAS MAD THE FUT CAT WAS MAD

9 III. Point mutation Normal Point mutation mRNA Protein Stop mRNA Protein Replace G with A

10 Point mutations in our lives! -Sickle cell anemia is a blood disease caused by a SUBSTITUTION point mutation. -A single nucleotide is changed from “A” to “T” which causes the amino acid to change from glutamic acid to valine: Amino acids: Thr – Pro – Glu – Glu Normal: ACT CCT GAG GAG Normal: ACT CCT GAG GAG Sickle cell: ACT CCT GTG GAG Sickle cell: ACT CCT GTG GAG Amino acids: Thr – Pro – Val – Glu

11 Point mutations in our lives! -People with sickle cell anemia often experience a lot of pain and swelling and have trouble exercising.

12 IV. More Gene Mutations  Frameshift Mutations – will affect several if not all of the following codons! (MAJOR PROBLEM!) will affect several if not all of the following codons! (MAJOR PROBLEM!) Example: “Deletion” – one base was left out. Example: “Deletion” – one base was left out. AAU CGA GGA …  AAC GAG GA… AAU CGA GGA …  AAC GAG GA… (What is missing?) AAU CGA GGA …  AAC GAG GA…

13 IV. Frameshift mutation -A frameshift mutation is when one nucleotide is inserted or deleted from the DNA or mRNA strand. -A frameshift mutation is worse…. WHY??? Ex: DNA TACTTCAAACCGCGTAACATT mRNA mRNA Protein

14 Difference between a substitution mutation and a frameshift mutation. substitution

15 THE FAT CAT WAS MAD… THE FAC ATW ASM AD… Deletions cause a shift in the codons…just like leaving a letter out, it makes no sense!

16 Other Frameshift Mutations:  “Insertion” – an extra base is added. ACC GAU GUC…  ACU CGA UGU C… (What was added?) ACC GAU GUC…  ACU CGA UGU C…

17 THE FAT CAT WAS MAD THE FAD TCA TWA SMA D… Once again, this makes no sense!

18 Questions: Is this a substitution mutation or a frameshift mutation? -It’s a substitution mutation because G was replaced with a T!

19 Questions: THE DOG BIT THE CAT THE DOG BIT THE CAR Substitution or frameshift? Substitution!

20 Questions THE DOG BIT THE CAT THE DOB ITT HEC AT Substitution or frameshift? Frameshift! The mutated sentence makes no sense (non-sense) and thus the protein will not be made

21 Chromosome Mutations  …are usually damaging.  An entire piece of a chromosome may be deleted, moved or damaged.  ALL INFORMATION ON THE AFFECTED SECTION MAY BE LOST OR FOREVER CHANGED (and is useless).

22 Types of Chromosome Mutations  Deletion – the whole chromosome is gone!  Duplication – now you have 2 sets of the same stuff.  Inversion – one part of a chromosome gets moved to another area on the SAME chromosome.  Translocation – a section of a chromosome is stuck on a DIFFERENT chromosome

23 Chromosome Mutations

24 Summarizing Can you…  define mutations  explain how mutations occur when – DNA Replication or Meiosis how – radiation &mutagenic chemicals  recognize point (N-base) mutations (insertions, deletions and substitutions)  recognize chromosomal mutations (deletion, duplication, inversion, insertion, translocation)


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