Karyotyping (from Estandarte) Flashcards
Chromosomes continue to condense until it reaches the ___ state
Metaphase
___ allows the proper visualization of chromosomes
Staining
___ can lead to banding
Staining
A consequence of differential staining along the length of the chromosome
Banding
T/F: Banding provides more information about the chromosome
T
Visible dyes such as Giemsa are used in ___ microscopy, while quinacrine are used in ___ microscopy
Light
Fluorescence
Heavy metal complexes are used as stains in ___ and ___ microscopy
Fluorescence
Electron
Advantage of light microscopy
Little damage on the chromosome
Advantage of fluorescence microscopy
High sensitivity and specificity
T/F: Both light and fluorescence microscopy have limited resolution
T
Electron microscopy includes ___ and ___ microscopy
TEM (transmission electron)
SEM (scanning electron)
The sample thickness of TEM is limited to approximately ___ nm, while SEM is only ___-___
100
surface-sensitive
___ ___ ___ ___ provides high resolution and 3D-images of the chromosome structure
Coherent x-ray diffraction imaging (CDI)
Enhance the contrast between different cellular components
Staining
T/F: Banding can be used to study abnormalities in the chromosome such as deletions, insertions, or translocations
T
___ heterochromatin consists of satellite DNAs
Constitutive
___ heterochromatin is a condensed and transcriptionally silent chromatin region
Facultative
Banding technique for constitutive heterochromatin
C-banding
Banding technique for facultative heterochromatin
G- or Q-banding
Banding technique for euchromatin
R-banding
___ interactions usually involve metal stains wherein the metal coordinates with the nitrogen atoms of the base pairs of the DNA
Covalent
The coordination of metal with nitrogen atoms often occurs at position ___ of ___ or ___
7
adenine or guanine
The coordination of metal with nitrogen atoms often occurs at position 7 of adenine or guanine occurs at some ___ stains and results to ___ ___ binding
Platinum
Major groove
___ ___ occurs with stains that have a functional group containing an electronegative atom such as nitrogen or oxygen
Hydrogen bonding (H-bonding)
During hydrogen bonding, the sites are position of __ of adenine, position __ of cytosine, and position __ of guanine
4
6
2
H-bonding leads to ___ ___ or ___ ___ binding
Major groove
Minor groove
____ ____ involve stains that have cationic groups
Electrostatic interactions
Electrostatic interactions result to ___ binding
external
Pi-pi interactions occur with stains that have ___ ___ groups
planar aromatic
___ is a visible light dye that binds to DNA through intercalation and thus, is used for chromosome staining
Giemsa
Giemsa is a mixture of cationic thiazine dyes, most importantly ___ __ and anionic eosin dyes such as ___ __
Azure B
Eosin Y
Staining of the chromosomes involves the formation of thiazine-eosin precipitate in a __ molar ratio
2:1
The formation of the precipitate in Giemsa staining is favored on a ___ (hydrophobic or hydrophilic) environment
Hydrophobic
The most widely used banding method for cytogenetic analysis that was first developed by Seabright
G-banding
This banding technique is advantageous in the aspect of stability and resolution of the band produced
G-banding
T/F: Fluorochromes are more stable and capable of producing clearer bands than visible light dyes
F (visible light dyes are more stable and capable)
Most common pretreatment method used in the digestion of the chromosomes in G-banding is with a ___ such as ___
protease
trypsin
Another pretreatment during G-banding aside from trypsin
Incubation of the chromosomes in hot-saline citrate or detergent/urea solution
Role of pretreatment methods in G-banding
Extract a characteristic subset of proteins from the chromosomes
Responsible for the banding and a reflection of the difference in the structure of the various chromosomal regions
Differential extraction
