EQ: how was DNA s function and structure discovered?

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1 EQ: how was DNA s function and structure discovered?

2 Intro to DNA

3 EQ: How was DNA s function discovered? I. Search for the Secret Miescher (1869) not a protein discovered DNA Morgan fruit flies chromosomes contain genes didn t know function Genetic material function: Store genetic info Copy genetic info Express genetic info

4 I. Search for the Secret Griffith mice, bacteria transformation later: Avery & McCarty: it was DNA Hershey, Chase bacteria, virus DNA

5 The Structure of DNA Franklin X-rays helix Watson, Crick final model EQ: How was DNA s structure discovered?

6 The Structure of DNA

7 Structure of DNA

8 Vocab: Helix 2 polymeric strands Nucleotides Antiparallel Deoxyribose Nitrogenous bases Phosphodiester bonds 5 -> 3 direction Purines Guanine Adenine Pyrimidine Thymine/Uracil Cytosine Complementary Structure of DNA

9 EQ: how does DNA get copied/replicated?

10 DNA replication Meselson & Stahl semiconservative helicase unzips primers tell where to start DNA polymerase plays matchmaker 5-3 (downhill) antiparallel, so leading & lagging strands gaps repaired by ligase

11 Vocab: Template Replication fork Helicase 3 / Leading strand 5 / Lagging strand Okazaki fragments DNA polymerase Replication of DNA

12 II. RNA & Protein Synthesis RNA 1. structure 2. types a. mrna, rrna, trna 3. Transcription...

13 Section 12-3 Transcription Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase RNA DNA

14 Transcription

15 II. RNA & Protein Synthesis A. The Genetic Code 1. mrna triplets a. UUU= phe b. AGU= ser ex: AUGCGCCAGUGA = met - arg - glu

16 Translation Nucleus Phenylalanine trna Lysine mrna Methionine Ribosome mrna Start codon

17 Translation (continued) The Polypeptide Assembly Line The ribosome joins the two amino acids methionine and phenylalanine and breaks the bond between methionine and its trna. The trna floats away, allowing the ribosome to bind to another trna. The ribosome moves along the mrna, binding new trna molecules and amino acids. trna Growing polypeptide chain Ribosome Lysine trna mrna mrna Ribosome Translation direction Completing the Polypeptide The process continues until the ribosome reaches one of the three stop codons. The result is a growing polypeptide chain. Go to Section:

18 Translation

19 Translate this (write the first three letters of the a.a. s) 1.AUG,GAG,GAA,AUA,GAU,UGA 2.AUG,GUG,GAA,AUA,GAU,UGA 3.AUG,GGG,AAA,UAG,AUU,GA 4.AUG,GCA,GGA,AAU,AGA,UUG,A

20 Genetic Modification & Gene Expression Ch 15.3, and Ch 16

21 How do enzymes know where to cut DNA? restriction enzymes Used by bacteria to get rid of foreign DNA Cut DNA at: palindromic base sequences

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23 How can we make lots of copies of DNA? PCR Polymerase Chain Reaction Needs:

24 How can we sort DNA fragments? Gel Electrophoresis Sorts the cut DNA fragments by size Long to short Lets us compare two different DNA molecules Different molecules will have different restriction sites thus frags of diff lengths

25 How can we use electrophoresis to compare DNA? Gel Electrophoresis Normal!-globin allele 175 bp 201 bp Large fragment Ddel Ddel Ddel Ddel Sickle-cell mutant!-globin allele 376 bp Large fragment Normal allele Sickle-cell allele Ddel Ddel Ddel Ddel restriction sites in normal and sickle-cell alleles of!-globin gene Large fragment How many fragments? What sizes? 201 bp 175 bp 376 bp Electrophoresis of restriction fragments from normal and sickle-cell alleles

26 How can we compare DNA? DNA Fingerprinting Paternity which kids are from Mom and Dad? Crime Which suspect committed the assault?

27 How can we change organisms? GMOs Genetically Modified Organisms 90% all soybean and corn No evidence of biological or environmental harm Confers private ownership of otherwise commonly held life forms

28 How can we change genes? CRISPR Cas9 Clustered Regularly Interspaced Short Palindromic Repeats

29 How can we change genes? CRISPR Cas9 Clustered Regularly Interspaced Short Palindromic Repeats

30 How can we change genes? CRISPR Cas9 Clustered Regularly Interspaced Short Palindromic Repeats