Chater 8 Flashcards
Double helix DNA molecule winds around protein called
Histones
Histones
(H1, H2a,H2 , H3, H4)
Eight of these histones group together to form a unit called
Nucleosome
These nucleosome then wind in a helical fashion to form a coil called
Selenoid
The coil wraps even further to form
Supercoils
These supercoils form a fiber of DNA- protein called
Chromatin
these chromatins condenses even further called
Chromosome
detects the placement of nucleosomes
NUCLEASes
enzymes that cut the double helix in the linker
region (the part of the double helix that is exposed
between histones)
Nucleases
associated with histone HI
30- micron- fiber
first classic indicator of apoptosis
30- micron- fiber
state of the compaction of the DNA double heliX
CHROMOSOME TOPOLOGY
Closed Chromatin
Heterochromatin:
open chromatin
Euchromatin
distinguisned historically by their relative size
and centromere placement.
CHROMOSOME MORPHOLOGY
distinguisned historically by their relative size
and centromere placement.
CENTROMERE
is the site of attachment of the chromosome to the spindl apparatus.
CENTROMERE
 the connection made between microtubules of the splindle and a protein complex.
KINETOCHORE
Long arm
q
Short arm
p
CYTOLOGICAL STAINS
Feurgen’s, wrights, Hematoxylin
used to visualize chromosome.
Cytological stains
can react with specific chromosome regions.
FLUORESCENT DYES and CHEMICAL DYES
results in the formation of band patterns where
portions of the chromosome accept or reject the stain.
FLuORESCENT DYES and CHEMICAL DYES
stained with Fluorescent dyes such as Quinacrine and Quinacrine mustard
Q BANDING
gives an intense staining of the human y chromosome
affects gene activity requires fluorescent microscope
Q banding
Stained with chemical due, Giemsa Stain
G banding
Mild treatment for G banding
2x standard saline citrate for 60 minutes at 68 c
To extract or denature proteins before Giemsa staining was found to map abbrerations and most commonly used staining method
Trypsin or orther Proteolytic agents
Feulgen staining after treatment w/ DNase I.
G banding
centromere Staining is ABSENT.
G banding
results from deletion of genetic regions from both ends of the chromosome and a joining of the ends to form
ring.
RING CHROMOSOME
abnormal chromosome consisting of translocated or otherwise rearranged paris from two or more
unidentified chromosomes pined to a normal
chromosome.
DERIVATIVE CHROMOSOME
normal female karyotype
46,XX
Normal male karyotype
46,XY
results from extra chromosome 21
Down’s syndrome
caused by an extra X Chromosome in males (i.e.
47, xxy)
Klinefelters syndrome
widely used method to detect protein, RNA as well as DNA Structures in place in the cell or in situ.
INTERPHASE FISH
Growth of cells in culture is not required.
Interphase FISH
enhanced by the development of fluorescent probes that bind to metaphase chromosomol regions or to whole chromosomes
METAPHASE FISH
Probes that cover the entire chromosome or
whole chromosome paints, are valueble for
detecting small rearrangements that are not
apparent by regular chromosome banding
METAPHASE FISH
