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Mutations

Understand the impact of DNA mutations on protein synthesis and how they can lead to changes in amino acid sequences. Explore point mutations and frameshift mutations, their effects on protein production, and the potential consequences for cells and organisms.

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Mutations

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  1. Mutations

  2. Whth appensw henp roteins ynthesisg oesw rong? • A mutationis a change in the original DNA sequence, which may lead to a change in the amino acid sequence.

  3. Whth appensw henp roteins ynthesisg oesw rong? • A mutation occurs when the original DNA sequence is not copied properly during replication or protein synthesis.

  4. Whth appensw henp roteins ynthesisg oesw rong? • Mutations can be spontaneous or caused by radiation and/or chemical exposure.

  5. Whth appensw henp roteins ynthesisg oesw rong? • The result of a mutation is a change in the amino acid sequence.

  6. Whth appensw henp roteins ynthesisg oesw rong? • The necessary protein may not be made or is defective. • This can change the traits of the cell or organism. • Only mutations in sex cells (egg or sperm) or in the gamete can result in heritable changes.

  7. Fill It In … Why does a change in DNA mean a change in the protein could happen?

  8. Blame it on the DNA There are 2 types of gene mutations: 1. Point(or substitution) mutations occur when a single base is replaced with a different base. (For example, A is replaced by C.) • Ex. GATTACA --> GAGTACA

  9. There are 2 types of gene mutations: • A point mutation, if it occurs on a gene, may result in the change of a single amino acid within the protein. • Sickle cell anemia, a disease that results in misshapen red blood cells, is caused by a point mutation.

  10. Example- Sickle Cell Anemia • Sickle cell anemia gets its name from the shape of red blood cells in affected individuals • give the cells a crescent or sickle appearance in contrast to the doughnut-like appearance of normal cells • CTC to CAC in DNA

  11. There are 2 types of gene mutations: 2. Frameshift mutations occur when a single base is added (addition frameshift) or deleted (deletion frameshift) within the sequence.

  12. There are 2 types of gene mutations: • Because DNA and the mRNA copy are read three bases (a codon) at a time, this type of mutation “shifts” the reading frame. • Ex. GAT/TAC/ATT --> GAT/TAA/CAT/T

  13. There are 2 types of gene mutations: • The effect of a frameshift depends on the location of the addition or deletion. • The earlier within the gene sequence the base is added or deleted, the more amino acids will be changed.

  14. There are 2 types of gene mutations: • Huntington’s Disease, a disease that results in the progressive loss of nervous system function, may be caused by the insertion of several bases.

  15. Chromosomal mutations • Change in the number or structure of the chromosome. • Change location of gene • Or change the number of copies of genes

  16. Gene Mutations Examples • Downs Syndrome- Extra copy of chromosome 21 • Klinefelter syndrome: 47, XXY • Trisomy X: 47, XXX • 47, XYY males: • Monosomy X (Turner's syndrome): • Cri du chat (cry of the cat):

  17. Lactose Tolerance

  18. Fill It In … Compare/Contrast point and frameshift mutations using a Venn or T-chart:

  19. Check Yourself! • Define mutation. • What is the result of a mutation? • What are the two types of mutation? • What type of mutation is illustrated in the title of this section of notes (IV)? • Which type of mutation may affect a greater number of amino acids?

  20. Check Yourself! • Define mutation. A CHANGE IN DNA SEQUENCE • What is the result of a mutation? • What are the two types of mutation? • What type of mutation is illustrated in the title of this section of notes (IV)? • Which type of mutation may affect a greater number of amino acids?

  21. Check Yourself! • Define mutation. A CHANGE IN DNA SEQUENCE • What is the result of a mutation? A CHANGE IN AMINO ACID SEQUENCE • What are the two types of mutation? • What type of mutation is illustrated in the title of this section of notes (IV)? • Which type of mutation may affect a greater number of amino acids?

  22. Check Yourself! • Define mutation. A CHANGE IN DNA SEQUENCE • What is the result of a mutation? A CHANGE IN AMINO ACID SEQUENCE • What are the two types of mutation? POINT (OR SUBSTITUTION) AND FRAMESHIFT • What type of mutation is illustrated in the title of this section of notes (IV)? • Which type of mutation may affect a greater number of amino acids?

  23. Check Yourself! • Define mutation. A CHANGE IN DNA SEQUENCE • What is the result of a mutation? A CHANGE IN AMINO ACID SEQUENCE • What are the two types of mutation? POINT (OR SUBSTITUTION) AND FRAMESHIFT • What type of mutation is illustrated in the title of this section of notes (IV)? FRAMESHIFT (DELETION) • Which type of mutation may affect a greater number of amino acids?

  24. Check Yourself! • Define mutation. A CHANGE IN DNA SEQUENCE • What is the result of a mutation? A CHANGE IN AMINO ACID SEQUENCE • What are the two types of mutation? POINT (OR SUBSTITUTION) AND FRAMESHIFT • What type of mutation is illustrated in the title of this section of notes (IV)? FRAMESHIFT (DELETION) • Which type of mutation may affect a greater number of amino acids? FRAMESHIFT

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