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31 Cards in this Set
- Front
- Back
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how many H bonds in A-T
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2
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how many H bonds in C-G
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3
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where does the phosphodiester linkage occur
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between the 3' OH group and the 5' Phosphate group
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most DNA is in which form
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B
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what happens when relative humidity of B-DNA falls bellow 75%
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B DNA transforms into A DNA which is more compact and wider
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what form does DNA methylation favor
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Z form
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what handed complex are A B Z forms
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A - right handed helixZ - left handed helix
B - right handed helix |
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what can mediate the control of gene expression caused by DNA methylation
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B DNA transforming into Z DNA
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how many A are A B Z forms
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A - 26 A
B - 20 A Z - 18 A |
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how many chromosomes in human genome
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46
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what is a unique DNA sequence present in few/single copies per genome
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genes
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what are the two repeted sequences in Genome
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middle repetitive DNA
Highly repetitive DNA |
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what does middle repetitive DNA do
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it codes for histones, tRNA, and mRNA
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what does highly repetitive DNA do
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they are clusters of nearly identicle sequences that may function to line the chromosomes during cell division
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what holds DNA together
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covalent bonds
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what is the reversal of DNA denaturation
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annealing
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what can cause DNA denaturing
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local enzymes, DNA binding proteins, heat
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what charge do histones have and DNA have
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histone = +
DNA = - |
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DNA rapped around histone 2 times is what
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nucleosome
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fibers that are coils of 6 nucleosomes
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300 amstrong fibers
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what are g rich, species specific oligonucleotides
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telomeres
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what is G1/G2
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growth
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what is S
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synthesis
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M
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mitosis
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what does HIV use to turn RNA > DNA
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reverse transcriptase
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what can we do to treate AIDs
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reverse transcriptase has low fidelity and often results in errors. AZT metabolized in body into azido-TTP which is analogous to TTP. azido-TTP has azido bonded to the 3' position on pentose. since its on the 3' position which usually has an OH group phosphodiester linkages can't be form which prevents reverse transcriptase from replicating the viral genome to take over the cell
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how many oxidative modifications have been found
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20
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how does oxidative damage change
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it increases with age and age related deseases
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what catalyzes DNA oxidation
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metal ions
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what is an oxidative modification of DNA and what occurs
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8-oxo-G is an oxidative modification of DNA that can be fixed by excision but results in the C-G being replaced with A-T during DNA replication
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what does smoking do to DNA oxidation
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it increases the level of DNA oxidation products such as 8-oxo-G
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