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15 Cards in this Set
- Front
- Back
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DNA Structure
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- backbone of sugar-phosphate-sugar bonds
- to polymer nucleotide chains - held together by hydrogen bonds |
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What are the Bases
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- A pairs with T (U) (2 bonds)
- G pairs with C (3 bonds) - two ring base pairs with one ring base - |
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Chromosome
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- structures DNA is packed into
- proteins bind to DNA and fold it - made of chromatin |
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interphase chromosome
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- extended in long threads
- chromosome duplication |
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mitotic chromosome
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- highly compacted
- duplicated chromosomes can be readily seperated |
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telomeres
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repeated nucleotide sequence that enable the ends of chromosomes to be replicated
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origins of replications
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Nucleotide sequence where DNA duplication begins
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centromeres
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- specialized DNA sequence
- allows one copy of each chromosome to be allocated to each daughter cell -located at mitotic spindle |
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chromatin
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- complex of DNA and proteins
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nucleosomes
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- first level of DNA packing
- DNA wound around core of histones (histone octamer) |
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histones
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- chromosome protein
- mostly positive - binds to negatively charged sugar-phosphate backbone of DNA |
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heterochromatin
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- highly condensed interphase chromatin
- concentrated in centromere and telomere regions - genes within are not expressed - One X femal gene is always silenced by this |
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histone modification and affect chromatin packing
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- histone H3 modification attracts specific proteins
- those proteins attract more modified histone - heterachromatin spreads down chromosome - can inactivate genes - bind chromatin tighter |
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What processes does DNA packing affect in the cell.
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Gene expression
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histone octamer
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- 8 histone proteins in nucleosome
- 4 molecules - Histone H2A - Histone H2B - Histone H3 - Histone H4 |
