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Genes & Chromosomes PowerPoint Presentation
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Genes & Chromosomes

Genes & Chromosomes

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Genes & Chromosomes

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  1. Genes & Chromosomes Chromosomes - single large DNA molecule and its associated proteins, containing many genes; stores & transmits genetic info Gene - a chromosomal segment that codes for a single functional polypeptide chain or RNA molecule Genome - all of cell’s genes + intergenic DNA (<10% of genome is genes) chromatin (2 chromatids)

  2. Genes & Chromosomes Genomes Species/VirusGenome size HIV 9000 bases Bacteriophage l 48,500 bp Flu virus 1.8 million bp Bacteria (prok) 4.6 million bp Yeast (euk) 15 million bp C. elegans (worm, euk)) 97 million bp Human (euk) 3 billion bp

  3. Genes & Chromosomes Introns & Exons Eukaryotic genes have many intervening sequences between gene sequences gene sequences intervening sequences

  4. Genes & Chromosomes Size of genome vs. size of cell

  5. Genes & Chromosomes Compaction of DNA

  6. Genes & Chromosomes Compaction of DNA Beads-on-a-string Protein (histones, basic) + DNA (acidic) = Nucleosome

  7. Beads on a String (in Colorado)

  8. Genes & Chromosomes Compaction of DNA Beads-on-a-string

  9. Genes & Chromosomes Compaction of DNA Supercoiling Relaxed

  10. Genes & Chromosomes Compaction of DNA Important for DNA packaging, DNA replication Topoisomerases can underwind and/or relax DNA