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Understanding DNA, Mutations, and Protein Synthesis

Explore the fundamental concepts of DNA, how it codes for proteins, and the various types of mutations that can occur. Learn about the processes of transcription and translation, the roles of mRNA and tRNA, and the significance of ribosomes in protein synthesis. Understand the implications of gene mutations, including point mutations, insertions, and deletions, as well as chromosomal mutations and their causes. This comprehensive overview will prepare you for your upcoming test by reviewing crucial genetic concepts and their effects on organisms.

angelica-figueroa
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Understanding DNA, Mutations, and Protein Synthesis

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  1. Do Now Aim: Describe how your body uses DNA? What is DNA used to code for? Homework: Castle Learning Assignment #7, Test Friday, Quarterly Thursday of next week

  2. Review • Describe transcription and where it occurs within the cell? • What is the difference between mRNA and tRNA? • How do ribosomes play a role in protein synthesis? • What happens if RNA polymerase makes a mistake transcribing the gene?

  3. Genetic Mutations

  4. Mutations • Gene mutations occur in DNA. • These mutations may be inherited or may occur over time. • Not all mutations are harmful. • A mutation in DNA is a change in a base pairing that may result in an altered protein.

  5. Mutations • Base pairs change • May or may not alter amino acid sequence • Met-Ala-Trp-Arg-Ser-Asp-Gly-Lys-Stop A change in amino acid sequence will change the protein structure.

  6. Types of Mutations • Point Mutations: Base pair error • Substitution: when a single base pair is substituted for another • Deletion: when a base pair is removed • Insertion: when a base pair is added • Deletion and insertion can cause a frame shift. • Triple repeat mutation causes a repeat of 3 amino acids. Such disorders are fragile x, huntingtons, myotonic dystrophy.

  7. Point Mutations – a change in DNA involving a single base pair May change amino acid or may not.

  8. Point mutations - substitution • A substitution of an A for a T in the 6th codon cause diseases such as sickle cell

  9. Insertion/Deletion Mutations

  10. Trinucleotide Repeat Disorders • This causes diseases such as Huntingtons disease. • Caused by an excessive amount of CAG repeats • Normal level 6-35 repeats • Disease level 38-180

  11. Causes of Mutations • Can be passed down from parents. • Chemicals mutagens can cause mutations • Radiation • Sunlight / UV light • Replication or transcription errors

  12. Aim: What is the difference between a chromosomal mutation and a gene mutation? Do Now State three causes of mutations. Homework: Text Book Pg 353 questions 1-11, test Friday

  13. Mutations Alter Proteins • Proteins form improperly • May be shorter or longer then normal • Go to areas where they are not needed Normal Hemoglobin Mutated Hemoglobin

  14. What do we know about Mutations?

  15. Questions: • State why deletion or insertion mutations could be mush worse than a point mutation? • When there is a mutation what is going to be affected? • How could a mutation through off homeostasis?

  16. Chromosomal Mutations

  17. Sources of mutations • Nondisjunction • during meiosis a cell ends up with only one member of a homologous chromosome. An unequal separation. This can lead to disease such as down syndrome. • http://www.zerobio.com/independent_assortment.htm

  18. Sources of mutations • Polyploidy • when one or both of the parents gives a full diploid set of chromosomes leaving the offspring with a 3n or 4n number. • This condition occurs in plants for the most part. The plants that this occurs in with are sterile and also larger.

  19. Sources of mutations • Chromosome structure alterations • Translocation • when a segment of one chromosome breaks off and binds to a non homologous chromosome.

  20. Sources of mutations • Addition • occurs when a segment breaks off one chromosome and reattaches to another

  21. Sources of mutations • Inversion • occurs when a segment breaks off and reattaches in reverse on the same chromosome.

  22. Sources of mutations • Deletion • occurs when a segment breaks off and does not reattach to any other chromosome.

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