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CHAPTER 10 MOLECULAR GENETICS NUCLEIC ACIDS to PROTEINS:

CHAPTER 10 MOLECULAR GENETICS NUCLEIC ACIDS to PROTEINS:. STRUCTURE REPLICATION PROTEIN SYNTHESIS. DNA is the unit of heredity. it is transmitted from parents to offspring in reproductive cells called gametes. (meiosis) CHROMOSOMES are… DNA coiled around HISTONE

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CHAPTER 10 MOLECULAR GENETICS NUCLEIC ACIDS to PROTEINS:

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  1. CHAPTER 10MOLECULAR GENETICSNUCLEIC ACIDS to PROTEINS: STRUCTURE REPLICATION PROTEIN SYNTHESIS

  2. DNA is the unit of heredity. it is transmitted from parents to offspring in reproductive cells called gametes. (meiosis) CHROMOSOMES are… DNA coiled around HISTONE proteins then supercoiled into a compact shape. This is important for cell division.

  3. 1953 FRANKLIN, WATSON & CRICK discovered the structure of DNA

  4. (NOT ON TEST… just thought you’d like to know) X-ray diffraction crystallography is a technique that was used to help scientists learn the structure of DNA. (Rosiland Franklin)

  5. DNA STRUCTURE Double stranded • 2 polymer chains of nucleotide monomers • Covalent bonds joining amino acid monomers “sugar phosphate backbone” • Hydrogen bonds joining the two strands through nitrogen-containing-bases “A”, “T”, “G” or “C

  6. FUNCTION Unit of Heredity • Easily copied (Sphase) • 2 template strands • Gene copied into mRNA is instructions to assemble protein.

  7. THE DOUBLE HELIX sugar-phosphate backbone or “uprights” of the ladder base-pairs are the “rungs” of the ladder

  8. DNA NUCLEOTIDES DeoxyriboNucleic Acids are made of 3 parts: Phosphate Group Sugar = deoxyribose Nitrogen-containing base: A (adenine) T (thymine) G (guanine) C (cytosine) RNA NUCLEOTIDES RiboNucleic Acid are made of 3 parts: Phosphate Group Sugar = RIBOSE Nitrogen-containing base: A (adenine) U (uracil) instead of T G (guanine) C (cytosine)

  9. Nitrogen Containing base phosphate group sugar The nucleotide is the chemical building block of NUCLEIC ACIDS

  10. There is no THYMINE base in RNAURACIL takes it’s placeURACIL is a molecular mimic of THYMINE and does it’s same job

  11. Base-Pair Rules or Chargaff’s LAWS: purine-pyrimidine Adenine-Thymine Thymine-Adenine 3. Guanine-Cytosine Cytosine-Guanine RNA Uracil-Adenine Adenine-Uracil purines (A & G) pyrimidines (T & C)

  12. Each nucleotide’s partner is called it’sCOMPLEMENT • A • T • G • C • A • T • C • C • A • G • C • T • T Tell me the complements to this nucleotide sequence….

  13. Each nucleotide’s partner is called it’sCOMPLEMENT • A • T • G • C • A • T • C • C • A • G • C • T • T A A G C T G G A T G C A T (DNA) A A G C U C C A U C G A U (RNA)

  14. Chargaff’s Rule… The amounts of A & T match, so do the Amounts of C & G (where the base-pair rules came from). if the DNA is 35% A, then… What are the values for T, C, G?

  15. If A = 35% and A = T… then T=35% • Since 35+35=70 and 100-70=30, G+C=30 • If G=C… then G = 15% and C = 15% • ANSWER:A= 35%, T= 35%, G = 15%, C= 15% • QUESTION: What are the values of A,T,G, and C if the DNA is 20% G? • ANSWER: A=30%, T=30%, G=20%, C=20% • QUESTION: What are the values of ATC&G if the DNA IS 10% T? • ANSWER: A=10%, T=10%, G=40%, C=40%

  16. DNA REPLICATION- copying the DNA. • ENZYMES USED: • HELICASE-open DNA • DNA POLYMERASE-build polymer • DNA LIGASE-connect fragments • NUCLEOTIDES USED: • DNA NUCLEOTIDES base-pair rule • SEMICONSERVATIVEREPLICATION: • 2 strands: each is 1/2 old & 1/2 new • Leading strand- continuous • Lagging strand- okazaki fragments • Polymerase moves along the template strand in a 3’ to 5’ direction. • New strand is built 5’ to 3’

  17. The 5’ end has the phosphate Notice, the two strands run anti-parallel (opposite).

  18. SEMICONSERVATIVE REPLICATION… each strand of the DNA double helix acts as the “template” or instructions to build the matching strand

  19. Mutations do occur but are fixed by enzymes. 1/100,000 nucleotides are incorrectly placed Enzymes fix most mistakes reducing the number to 1/ billion base pairs Mutations (changes in the DNA sequence) can mean changes in phenotypes. They are the fuel for evolution.

  20. What is the connection between your genes (genotype) and how you look (phenotype)??? PROTEIN

  21. PROTEIN SYNTHESIS Central dogma = DNA --> RNA --> protein

  22. DNA (instructions) REMAIN IN THE NUCLEUS PROTEINS ARE ASSEMBLED OUTSIDE THE NUCLEUS on RIBSOMES

  23. DNA… the instructions • double stranded • twisted shape • RNA… the workers • mRNA- single stranded • rRNA- globular form • w/ proteins • tRNA- single stranded, hairpin loop • PROTEIN… the product • Amino acids strung together

  24. molecular model of tRNA I made while working at my old Job.

  25. TRANSCRIPTION making mRNA, tRNA, and rRNA

  26. The promoter has the sequence TAC which causes the RNA polymerase to attach to the beginning of the template chain and mRNA to be made. The terminator sequence causes the RNA polymerase to release both the DNA and the newly formed mRNA. There are 3 different terminator signals: ACT, ATT, and ATC.

  27. TRANSCRIPTION

  28. TRANSLATION 3 types of RNA work together to produce proteins proteins are chains of amino acids bonded together by peptide bonds

  29. TRANSLATION • Ribosome attaches to start codon on mRNA (AUG). • 1st tRNA w/ anticodon (UAC) binds to start codon w/in ribosome. • 2nd tRNA w/ matching anticodon to 2nd codon binds. • Peptide bond is formed between amino acid #1 and amino acid #2. • First tRNA leaves. • Ribosome moves to next codon on mRNA and tRNA #3 moves in…. Peptide bond.REPEAT • When stop codon is reached (UAA, UGA, UAG) release factor breaks binds instead of tRNA. • All parts separate.

  30. How can 4 nucleotides code for 20 different proteins?????????????? read the nucleotides as sets of three 3 (4) 4 x 4 x 4 = 64 combinations

  31. codon anticodon Nucleotides have meaning in sets of THREE.

  32. Don’t Be tricked The CODE can be cracked using this table. Use it to determine which of the 20 amino acids each mRNA codon- codes for.

  33. WHICH AMINO ACID? DNA Triplet is TTT Codon is AUG Anticodon is CCC ACT

  34. WHICH AMINO ACID? DNA Triplet is TTT Codon is AUG Anticodon is CCC ACT OK… I will! ANSWERS: Lys Met Gly STOP

  35. …G A T T A C A T A……C T A A T G T A T…

  36. A A U …G A T T A C A T A… U A U G C A RNAnucleotides RNA polymerase

  37. A A U …G A TT A CA T A… U A U G C A RNAnucleotides RNA polymerase

  38. A A U …G A TT A CA T A… U A U G C A RNAnucleotides RNA polymerase

  39. WRITE THE CORRECT LETTER BELOW EACH SYMBOL. USE “BASE PAIR” RULES TO WRITE THE mRNA TRANSFER THE CODONS BELOW. USE “BASE PAIR RULES” TO WRITE THE ANTICODONS. USE CODONS & THE CHART TO FIND AMINO ACIDS.

  40. CHECK YOUR WORK. HOW DID YOU DO? ANY QUESTIONS?

  41. YOUR Classwork/ homework… plus the Other sheets.

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