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