Lecture 1 Flashcards
Cytology vs cytogenetics
Study of the whole cell’s genetics
Study of structure and function of chromosomes
Heterochromatin vs euchromatin
Tightly packed. Loosely packed
Condensed. Relaxed
Darkly stained. Lightly stained
Genetically inactive. Active
Eukaryotes only. Both
Late replication. Early
Sticky. Not sticky
Structure and regulation. Transcription and variation
Feulgen positive is..
Heterochromatin
When does the membrane disintegrates
When max condensation
Prometaphase
Metaphase
Chromosomal theory of inheritance
1.nuclear subs control form and structure of cell, divide to give equal products
2.egg loses half nuclear subs replaced by sperm
3.sexual reproduction
4.no difference bet egg and sperm
5.sexual is variability
Telomere function
Maintained by
Seal and maintain integrity
Telomerase enzyme
Reduction in repeats aging and death
Chromosomes are divided acc to
Length
Centromere position
Presence or absence of satellite
Karyotype
Karyogram
Idiogram
Chromosome complement
Pic of chromosomes arranged as homologous pairs
Diagram of karyotype
Karyotyping
Process of pairing and ordering all chromosomes by standardized staining procedures to detect anomalies.
Staining types
G banding (giesma)
C banding (centromeric)
Ag NOR staining (nucleolar organising regions)
R banding (reverse banding)
Q banding (quinacrine)
Iscn
International system for human cytogenetic nomenclature
Each area of a chromosome is given a number with 1 closest to centromere
Abbreviations
Del
Dic
Fra
I
Inv
R
Deletion
Dicentric
Fragile site
Isochromosome (list arm replaced by ither ones replication)
Inversion
Ring chromosome
Abbreviations type 2
Der
Dup
H
Ins
Mat
T
Derivative , no centromere
Duplication
Heterochromatin
Insertion
Maternal origin
translocation
Where is heterochromatin found
Beneath nuclear lamina around nucleolus (nucleolus associated chromatin)
Peri centromeric regions
Telomeres
Adjacent to nucleolar organiser regions (NOR)
Heterochromatin remains condensed during…and..
Interphase
Early prophase
