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15 Cards in this Set
- Front
- Back
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What are the three components of DNA?
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1. sugar (deoxyribose)
2. an acid 3. organic "bases": ATCG |
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What are three properties of the nucletoide bases?
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1. weakly basic in solution
2. hydrophobic and aromatic 3. planar molecules that show resonance |
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What does resonance do to the bases?
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1. bases can interact with each other when stacked by van der Waal forces
2. Bases absorb strongly in UV light |
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What are the similarties of DNA and RNA?
What are the difference? |
1. Long polymers
2. nucleotide base 3. sugar residuce 4. phophodiester back bone 1. bases 2. sugar group |
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What are 5 traits of the WC DNA?
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1. sugar phosphate back bone is a right-handed helx
2. basese are internal 3. complementary bases 4. anti-parallel 5. the two sugar-phophate backbones are not exactly opposite to each other (major and minor grooves) |
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What are three forms of DNA and how do their helices turn?
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A = right
B = right Z = left |
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Are Z DNA postively or negatively supercoiled?
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Negatively
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What factors stabilze DNA structure?
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1. H bond of bp
2. Hydrophobic effects 3. stacked bases form van der Waals 4. DNA backbone interacts with cations |
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Which is more stable RNA or DNA, why?
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DNA because RNA has 2' and 3' carbons that can form phosphodiester bonds and DNA only has one which makes it more stable at a higher pH
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Why does DNA contrain thymine rather than uracil?
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B/C C will deaminate to U spontaneously.
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What is required for the biosynthesis of T?
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Folic acid from vegetables
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What happens in the absence of T?
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It will block excision-repair
1. mutagensis 2. chromosome breaks 3. brith defects 4. aging of cells 5. induction of cancer |
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What are three ways we can denature DNA?
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1. Heat
2. high pH (OH-) 3. Urea all these things destroy H bonds of bases |
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What is the hyperhcromic shift?
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denatured DNA abosrobs more UV light (260nm) than native DNA. THis is due to the lack of base stacking
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Why does DNA renaturation require annealing at intermediate temp. or pH?
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1. quick cooling gives inter-strand interactions
2. Snap back regions of DNA self complementation gives intra-stand interactions |
