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37 Cards in this Set

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what are the names of the two purines? The three pyrimidines?
adenine and guanine; thymine cytosine, and uracil
None
which pyrimidine is unique to DNA? To RNA?
Thymine; Uracil
what is the name for a pentose sugar with two hydroxyl groups attached?
ribose
what is the name for a base plus a ribose sugar unit?
ribonucleoside
what is the difference between a nucleoside and a nucleotide?
nucleotides have a phosphate group attached.
how are phosphate groups attched to nucleosides? At which point on nucleoside?
via ester linkages at 5' hydroxyl
why does DNA have a negative charge at physiological pH?
because pKa of phosphate group is 1-2 and phosphates have a negative charge at pH 7
what type of bond links together nucleotides?
3',5' phosphodiester bond
polynucleotides are always written in which direction?
5' to 3'
are DNA strands oriented in a parallel or antiparallel manner
antiparallel
which type of bonds help to bind purines and pyrimidines?
H-bonds
how many H-bonds are involved in pairing of A-T? C-G?
2; 3
other than H-bonds what is another force acting to hold complementary DNA strands together?
Hydrophobic effects
what is the name for the temperature at which one half of the double stranded DNA molecules denature into single-stranded DNA?
Melting Temperature
what is the name for the enzyme which unwinds double-stranded DNA?
helicases
what is the name for the type of DNA found in humans?
B-DNA
is B-DNA a right-or left-handed helix?
right-handed
how many base pairs are found per 360 turn in the B-DNA helix?
10
helical twist in B-DNA is equal to how many degrees? What is the rise of the B-DNA helix?
36; 3.4 Angstroms
what is the name for the two 'grooves' found in DNA molecules? The uneven nature of these 'grooves' is a result of which phenomenon?
major and minor groove; the fact that bases are attached at an angle to ribose sugar
which position in the ribose sugar is missing a hydroxyl group in DNA?
2'
is RNA normally single- or double-stranded
single stranded
which is more stable, DNA or RNA?
DNA
what is the name for the complex of DNA and proteins found in the nucleus?
chromatin
which 4 histones are responsible for creation of nucleosomes?
H2a, H2b, H3, H4
how many base pairs are wrapped around a histone complex?
140
what creates high histone affinity for DNA?
positively-charged amino acids such as lysine and arginine.
a solenoid fiber has how many nucleosomes per turn?
6
which histone is associated with linker DNA between nucleosomes?
H1
regions of DNA that are heavily acetylated are more or less likely to be transcribed to mRNA? These same groups would be more or less likely to be found in solenoid fibers?
more likely; less likely
what is the name for the enzyme responsible with the acetylation of histones? With the deacetylation?
histons acetylase; histone deacetylase
human somatic cells contain how many discrete linear molecules of DNA?
46 (23 chromosome pairs)
to what are solenoid fibers attached in the formation of chromatin?
chromosome scaffold
do bacterial cells have nuclei? Nucleosomes?
no; no
are mitochondrial DNA molecules circular or linear?
circular
is mitochondrial DNA passed via mother or father?
mother
which tissues are particularly vulnerable to mitochondrial DNA mutation?
muscle, heart, brain, and eye