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DNA Deoxyribose Nucleic Acid

DNA Deoxyribose Nucleic Acid. The Thread of Life. DNA is a double helix. A bonds to T: C bonds to G In man, the DNA molecule , if fully extended, would have a total length of 1.7 metres. If you unwrap all the DNA you have in all your cells, you could reach the moon ...6000 times!. DNA.

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DNA Deoxyribose Nucleic Acid

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  1. DNADeoxyribose Nucleic Acid The Thread of Life

  2. DNA is a double helix. A bonds to T: C bonds to G In man, the DNA molecule , if fully extended, would have a total length of 1.7 metres. If you unwrap all the DNA you have in all your cells, you could reach the moon ...6000 times! DNA

  3. DNA STRUCTURE DNA REPLICATION DNA

  4. NUCLEOTIDE Phosphate group-phosphodiester bond 5-Carbon sugar-deoxyribose nucleic acid (1 of the nucleic acids) Guanine-Purine Cytosine-Pyrimidines Adenine-Purine Thymine-Pyrimidines Held by hydrogen bonds One end of chain with free 5’ phosphate group Other end of chain with free 3’ hydroxyl group Adenine, thymine form two bonds Guanine, cytosine form three bonds Components of DNA

  5. COMPONENTS

  6. DNA is opened by enzymes (unzips) helicase Complementary nucleotides bond with the old strands- 2 strands created: ½ is the old strand; ½ is the new strand. DNA Replication

  7. DNA REPLICATION • TAKES PLACE IN THE NUCLEUS • END PRODUCT IS TWO IDENTICAL STRANDS • DURING CELL DIVISION- ONE STRAND • FOR EACH CELL • Replication occurs only in 5’(P) to 3’(OH) direction(DNA IS READ 3’ to 5’) • a. Replication of leading strand, 3' to 5' strand • 1. New strand grows from 5' to 3’end • 2. Elongates towards replication fork

  8. REPLICATION ENZYMES Helicase DNA polymerase Topoisomerase RNA primer ligase

  9. From Genotype to Phenotype • Protein synthesis--converting the genetic code (in DNA) into proteins that the body uses • 3 Steps involved • Transcription • RNA splicing • Translation

  10. DNA----RNA • DNA • DOUBLE STRANDED • DEOXYRIBOSE • NUCLEIC BASES • THYMINE • GUANINE • ADENINE • CYTOSINE • RNA • SINGLE STRANDED • RIBOSE • NUCLEIC BASES • URACIL • GUANINE • ADENINE • CYTOSINE

  11. RNA • Differences from DNA • Single stranded (vs. Double stranded DNA) • Contains uracil in place of thymine • Ribose sugar (instead of deoxyribose) • 4 Types of RNA preMRNA---transcribes the message from the DNA(rough blueprint) • mRNA (messenger RNA)-carries message to to ribosome(final blueprint) • rRNA (ribosomal RNA)--makes up the ribosome(forman that assembles parts of protein in a specific order) • tRNA(transfer RNA)--carries amino acids to ribosomes

  12. tRNA • Anticodon of MRNA • Wobble to take in all possible aa combinations of 3 nitrogen bases • Carries specific aa on 3’ on of strand

  13. DNA TRANSCRIPTIONDNA- GIVES CODE TO preRNA or hnRNA

  14. PROCESSING

  15. RIBOSOME STRUCTURE A site - attracts Trna P site - forms peptide bonds between aa of protein E site - where Trns leave ribosome and aa chain elongates 5’ end with initiator sequence attaches to small subunit Large subunit goes over small at the A site. Attracts 1st Trna with aa Met

  16. DNA TRANSLATIONtRNA translates mRNA into proteins

  17. SUMMARY

  18. RNA is single stranded RNA has uracil instead of thymine A-U DNA is double stranded DNA has thymine instead of uracil A-T Comparison of DNA and RNA

  19. Inheritance/ Genetic Counseling Cell function/protein synthesis Embryonic development/gene regulation Evolution/ phylogenetic relationships Medicine/genetic diseases Genetic engineering/ recombinant DNA Understanding DNA

  20. Changes in Chromosomes • Mutation--a change in the sequence of DNA nucleotides (nitrogen bases) • Causes a change in the protein formed • Causes a change in organisms’ phenotype (trait) • Effects of mutations? • Some have little or no effect • A few are beneficial • Most are harmful or lethal (fatal)

  21. Chromosomal Mutations • Deletion mutation--piece of chromosome breaks off and is lost; the new DNA strands are also missing a piece • Duplication--piece of chromosome breaks off and is inserted on homologous chromosome • Translocation--piece of chromosome breaks off and attaches to a different, non-homologous chromosome • Inversion--piece of chromosome breaks off, turns around and reattaches in opposite direction

  22. Mutations Illustrated

  23. Gene mutations • Frameshift mutation--deletion or addition of single (or few) nucleotides alters the amino acid sequence of the protein • Point (Substitution) mutation--wrong base is added in a position--new DNA chains will show the change

  24. Point Mutations

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