39 Cards in this Set
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List the functions of genetic material
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*contain complex info
*replicate faithfully
*encode the phenotype
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What happened in Henry Dawson's in vitro transformation experiment?
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injected dead bacteria and live bacteria
in a living system and have transformation from R living to S living
DNA causes bacterial transformation
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Avery, McCarty, MacLeod Experiment
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treatment of DNA with a DNA-degrading enzyme destoryed the S-strains ability to convert the R-strain into S. When treating other enzymes there was no affect on the transformation =
DNA is responsible for phenotypes
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DNA of prokaryotes and viruses
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negatively coiled, single chromosomes,
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Supercoiled DNA
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DNA is subjected to strain by over or under winding
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histone proteins
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role in chromatin, amounts equivalent to DNA, 5 major types- H1, H2a, H2b, H3, and H4, arginine and lysine abundant, highly conserved
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Nucleosomes
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8 histones with DNA wound around
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what does Histone H1 do?
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seals the nucleosome at the edge of the linker DNA
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levels of DNA packing
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-2 nm double stranded
-11 nm nucleosomes
-30 nm chromatin
-chromosome
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gene switched on
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- active (open) chromatin, unmethylated cytosines, acetylated histones
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gene switched off
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-silent (condensed) chromatin), methylated cytosines (red circles), deacetylated histones
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centromere
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where the spindle attaches to pull apart, 93% AT, no histones
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functions of telomeres
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-protect the ends of linear DNA molecules from deoxyribonuclease
-prevent fusion of chromosomes
-facilitate complete replication of the ends of linear DNA molecules
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T-loop
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the 3' overhang can loop around and pair with another part of the chromosome to further protect the ends
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DNA replication is
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semiconservative
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Meselson-Stahl Experiment
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1. Semi-conservative replication of DNA.
2. Position of DNA band after centrifugation is dependent on 14N and 15N content.
3 .50% 14N and 50% 15N in double helix = one thick band.
4. 100% 14N after a few more replications = two bands.
5. proved that DNA synthesis was semiconservative
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DNA polymerase
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responsible for synthesizing DNA strands
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Direction of DNA Replication
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5' to 3'
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dNTPS
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the raw materials for synthesis of the nedw strands
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What do the Mg2+ ions do during DNA replication?
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They are coordinated to the phosphate groups of the incoming NTP; one facilitates the attack on the 3' OH group, the other facilitates the displacement of the pyrophosphate
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Sanger's method of DNA sequencing
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Dideoxy terminators
> Starts with a primer.
> Chains terminate with dideoxynucleotides
> Fluorescent ddNTPs allow automation of DNA sequencing
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What are the 4 things that are put into every microtube in Sanger's method of DNA sequencing?
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Template DNA
Radiolabeled primer
DNA polymerase
All 4 dNTPs
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didNTP
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does not allow strand extension at 3'
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leading strand
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continuous
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lagging strand
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discontinous
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DNA polymerase III in E. Coli
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•containsten subunits. Synthesizes the leading and lagging strandsand contains proofreading activity.
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DNA replication in Eukaryotes
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-shorter RNA primers and Okazaki fragments
-replication in S phase
-multiple origins of replication
-nucleosomes
-telomeres
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DNA polymerase alpha
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DNA primase, initiation, priming of Okazaki fragments
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DNA polymerase Sigma in eukaryotes
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processive DNA synthesis
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DNA polymerase E
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DNA replication and repair in vivo
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PCNA (proliferating cell nuclear antigen)
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sliding clamp
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replication factor C (Rf-C)
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loading of PCNA
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ribonuclease H1 and ribonuclease FEN-1
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removal of RNA primers
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Short telomeres
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An increase in number of senescent cells (short telomeres) contributes to age related diseases, loss of function and early mortality.
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semiconservative replication picture
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conservative model picture
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dispersive model picture
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structure of purines
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double rings of carbon and nitrogen atoms
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pyridimines
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single ring
cytosine/thymine/uracil
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BIOL 3303: TEST 2