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 BI270 CELL BIOLOGY Part I
The Nucleus and DNA
VIRUSES
(in
Cell Biology??)
|
Virion particle = |
protein coat (capsid)
+ |
nucleic acid (DNA or RNA) |
Capsomeres
= capsid subunits |
Envelope = cell membrane
residue &
viral Ags |
Lytic
vs. proviruses [tumors,
etc.] |
See Bacteriophage
here
See Animal Viruses
here
The 3 DOMAINS of Living
Organisms:
| PROKARYOTES: |
nuclear
"region"; small ribosomes;
no membrane-bound organelles. [includes Bacteria and
Archaea] |
| EUKARYOTES: |
nucleus,
ER, GC, large ribosomes; histones, mitochondria, chloroplasts, microtubules, etc. |
Compare cell sizes and images here
Lynn
Margulis and the
ENDOSYMBIONT THEORY
1.
Mixotricha
paradoxa |
2.
Cyanophora
paradoxa |
3.
Prochloron spp. |
|
4. Eukaryotes
without mitochondria OR with aerobic bacteria |
|
5. RNA
sequences in bacteria, mitochondria and chloroplasts. |
|
6.
Thorsness and
Fox
-
nuclear and mitochondrial genes
|
.
|
Prokaryotes |
Eukaryotes |
Mitochondria |
|
small ribosomes |
large
ribosomes |
small
ribosomes |
|
no nuclear membrane |
nuclear
membrane |
DNA not
within membrane |
|
DNA circular |
DNA
linear |
DNA
circular |
|
no histones |
histones
present |
no
histones |
|
binary fission |
mitotic
division |
binary
fission |
|
no membrane-bound systems |
ER,
Golgi, vacuoles, etc. |
no
membrane-bound systems |
|
antibiotic sensitive |
antibiotic
resistant |
antibiotic
sensitive |
|
continuous DNA synthesis |
DNA
synthesis occurs only during S phase |
continuous
DNA synthesis |
|
no sterols |
sterols
present |
sterols
in OM, not in IM |
|
EMP &
TCA in cytoplasm |
EMP in cytoplasm |
TCA in matrix; |
|
ETS on cell
membrane |
TCA and ETS in mito. |
ETS on inner membrane |
|
SD with
Mn++ |
SD with Cu++ |
SD with MN++ |
|
d amino acids in cell
wall |
no d amino
acids in cell wall |
|
AUG codes for N-f-MET |
AUG codes
for MET |
|
flagella
composed of wound protein fibers (no microtubules) |
flagella
& cilia with 9 + 2
microtubule arrangement |
Check
on additional Endosymbiosis Info here
See an
Endosymbiosis diagram here
Meet Lynn Margulis
here
Margulis Laboratory Link
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Page
The
NUCLEUS & DNA
See Nucleus Diagram
See Nucleus TEM
Double membrane
= Nuclear Envelope
Intermembrane
(Perinuclear)
Space
NUCLEOPLASM vs.
CYTOPLASM
NUCLEAR
PORE COMPLEX
Þ
nucleoporin proteins
symmetrical vs. asymmetrical
distribution
Octamer
structure with central transporter
Nuclear
Localization Signal (NLS)
Importins
and Ran-GTP
Nuclear Export Signal
(NES) and
Exportin proteins
ALY-EJC-TAP Complex
VESICLES
Nuclear
Lamina
Þ
Lamins (proteins)
GRANULAR ZONE |
FIBRILLAR ZONE |
MATRIX |
NUCLEOLAR
ORGANIZER REGION Þ
rDNA genes Þ rRNA
and SPACER SEQUENCES
See Nucleolus TEM
BROWN &
GURDON Þ
Autoradiography in Xenopus
using 3H-Uridine (WHY??)
Click to
see Xenopus
CHROMOSOMES
Chromatin Fiber = DNA + proteins
KORNBERG
--
n
bodies = Nucleosomes
Þ
HISTONE
OCTAMER
2 x (H2A, H2B, H3, H4)
H1 inhibits RNA
Polymerase
arg & lys
content
What's in those HISTONES?
(Find Out)
DuPRAW
-- SUPERCOILING
Solenoid & Folder Proteins
Scaffold - non-histone proteins of the nuclear matrix
Condensin
and cohesin
proteins
Click on this
Image!
See
chromosome FOLDING here.
Centromere (DNA), Kinetochore (protein)
and SPINDLE FIBERS
PRIMARY CONSTRICTION
= Centromere
1.metacentric |
2. submetacentric |
3. acrocentric |
4. telocentric (rare) |
"acentric" = ??
SECONDARY
CONSTRICTION and the Satellite region
Euchromatin vs. Heterochromatin (Facultative
vs. Constitutive)
Polytene
Chromosomes: PUFFS
= ?? ?? Lampbrush Chromosomes
See POLYTENE
CHROMOSOMES here.
See
LAMPBRUSH CHROMOSOMES
Test yourself and find out MORE about
the NUCLEUS here!
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Page
DEOXYRIBONUCLEIC ACID
(DNA)
NITROGENOUS BASE (NB) = PURINE or
PYRIMIDINE
(NB) + PENTOSE (5C Sugar) =
NUCLEOSIDE
Deoxyribose = ??
NB + PENTOSE + PHOSPHATE = NUCLEOTIDE
See
more DNA diagrams here
CHARGAFF
Þ G
= C and A
= T
(WHY ??)
DNA is
DOUBLE-STRANDED |
Hydrogen
Bonds |
G º C or A = T |
|
WATSON
&
|
Þ
strands are Antiparallel
& |
Complementary (Template) |
|
CRICK
|
Þ Semi-conservative
Replication |
|
Þ
Phosphodiester
Bonds |
|
|
|
|
|
TAYLOR et al. |
Autoradiography |
Vicia
faba |
3H-Thymidine |
Þ
"PULSE & CHASE" |
Þ "hot" chromatids
|
|
See
TLaV's PowerPoint |
|
.
MESELSON
& STAHL: |
Equilibrium
Density Gradient Centrifugation |
[Cesium Chloride] |
Escherichia
coli |
15N (=
"heavy" nitrogen) |
Heavy DNA (all 1515N) |
| |
HYBRID DNA
(15N + 14N) |
LIGHT (regular) DNA (14N) |
See Meselson/Stahl Experiment diagrams here.
More Meselson/Stahl diagrams
| CAIRNS
|
Escherichia
coli |
| circular chromosome |
mesosome |
| ORIGIN of REPLICATION |
Theta Form (q ) |
| BIDIRECTIONAL REPLICATION |
5’
® 3’ only
!! |
KORNBERG et al.
Bacterial DNA
Replication in vitro
 |
DNA
template |
|
|
Deoxyribonucleoside Triphosphates (dATP, dGTP, dCTP, dTTP) |
|
|
Topoisomerases I & II (Topoisomerase II = Gyrase) |
|
|
Helicase |
|
|
Single Strand Binding Protein (SSB)
|
|
|
Primase (special RNA polymerase)
Þ
"Primosome"
= 4 + 6 |
|
|
DNA Polymerase III
Þ
TWO core polymerases 5’
® 3’ only!!
b-clamp
components,
g
loader, and t
holder components
|
|
|
LEADING Strand
Þ continuous synthesis |
|
|
LAGGING Strands
Þ
Okazaki Fragments = ??
|
|
|
DNA Polymerase
I
Þ
Exonuclease activity removes RNA primers and
adds DNA nucleotides [5’
® 3’ only!!];
[also a DNA Repair enzyme]. |
|
|
DNA Ligase
|
REPLICON
= location of DNA replication (prokaryotes: 2; eukaryotes: many)
EUKARYOTIC POLYMERASES
= a
and d ;
b and e ; g
| LAYBOURN & KADONAGA |
DELEGEANE & LEE |
|
RICH
Þ
Z-DNA |
regulation of GENE EXPRESSION
(uncoiling) |
|
methylation STABILIZES Z-DNA |
|
JAWORSKI
et al. |
Z-DNA
in vivo |
Compare Z
DNA and B DNA
CAN YOU ANSWER THIS?
If you digested a DNA preparation with acid at 100oC for 1 hour,
all four bases will be retrieved. You find equal quantities on a molar basis
of bases W and Z, and equal molar amounts of bases X and Y. Base X has no oxygen. Base X
had a higher mol. wt than base Y and base W had a higher mol. wt. than base Z. What is the
identity of all four bases?
      
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