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DNA
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DNA

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  1. DNA Nucleic acid found in the nucleus Carries hereditary information

  2. Chromosome Nucleic acid Polynucleotide Nucleotide

  3. Nucleotide Phosphate group Nitrogenous base O C pentose sugar C

  4. Polynucleotides Polymer ofnucleotides Phosphate-sugar “backbone” • Sequence of bases • - unique • - genetic code.

  5. Deoxyribonucleic Acid DNA • 2 polynucleotide strands • double helix • deoxyribose • A, T, G, C

  6. Purine Pyrimidine Thymine Adenine Guanine Cytosine http://www.youtube.com/watch?v=ZXt4pDVb2W0&feature=related (DNA structure, 10 min)

  7. DNA replication • chromatin condenses  chromosomes. • Section of the DNA helix unwinds • Free nucleotides bind with complementary bases on the DNA strand. • DNA double helix rewinds

  8. DNA REPLICATION Original DNA helix DNA strands separate Original (parent) anti-code strand Nucleotides building new strand New (daughter) code strand Original code strand New cells have exact copy of original DNA New anti-code strand

  9. New nucleotides

  10. DNA replication is semi-conservative. - new DNA = 1 old strand + 1 new strand • helps reduce the number of copy errors. • Enzymes control all processes, including “proofreading”

  11. Single chromosome – 1 DNA double helix Sister chromatids – 2 DNA double helices genes centromere DNA Replication One chromosome

  12. DNA Replication Each chromosome in an homologous pair replicates to form sister chromatids

  13. MENU Quick Quiz Key Words Videos Exercises

  14. KEY WORDS • Pentose sugars • Phosphate • Nitrogenous base • Purine • Pyrimidine • Adenine • Thymine • Guanine • Cytosine • Double helix • Chromosome • Chromatin • Replication • Base pairing • Complementary • Semi-conservative • Chromatids • Centromere

  15. EXERCISES Workbook • Read pp 78-80 • Questions 6-16 Pathfinder • Read p 53

  16. QUICK QUIZ 1 • The building blocks of organic molecules .... • The building blocks of nucleic acids ..... • How many polynucleotide strands in DNA? • Sugar found in RNA. • Base found in RNA but not DNA. • Chromosome found in men but not women. • A picture of a complete set of chromosomes. • Number of chromosome pairs in humans. • Two identical DNA molecules joined at a centromere. • Two chromosomes with the same genes.

  17. QUICK QUIZ ANSWERS • monomers • nucleotides • 2 • ribose • uracil • Y • karyotype • 23 • sister chromatids • homologous • The building blocks of organic molecules .... • The building blocks of nucleic acids ..... • How many polynucleotide strands in DNA? • Sugar found in RNA. • Base found in RNA but not DNA. • Chromosome found in men but not women. • A picture of a complete set of chromosomes. • Number of chromosome pairs in humans. • Two identical DNA molecules joined at a centromere. • Two chromosomes with the same genes.

  18. VIDEOS • http://www.icyou.com/topics/cancer/chromosomes-dna+ (47 sec) http://www.allthingsscience.com/video/715/Human-Chromosomes (chromosomes, 4min)http://videos.howstuffworks.com/hsw/6090-the-cell-the-nucleus-video.htm

  19. Nucleus • Control centre of cell • Contains chromosomes (DNA) • http://videos.howstuffworks.com/hsw/6090-the-cell-the-nucleus-video.htm (nucleus, 1 min)