Chromosome I Flashcards
What is karyotyping?
Determining the karyotype, to detect chromosomal abnormalities
Describe ways to use karyotyping
Number/Size/Morphology of chromosomes, Banding pattern, Regions of heterochromatin/euchromatin
Describe the process of karyotyping
Culture blood cells, add colchicine to stop metaphase
Spin cells, remove supernatant
Add hypotonic salt solution, resuspend cells
Add preservative to cell suspension, add one drop to slide, dry and stain
What is heterochromatin?
Highly condensed, most repeated, DNA arranged in tandem arrays with very few genes
What is the metacentric?
Arms of roughly equal length, centromere in middle
What is submetacentric?
Arms of unequal lengths, centromere slightly towards one end
What is acrocentric?
Very short arms with secondary constrictions that connect small pieces if DNA (stalks, satellites) to centromere. Centromere very near to one end
What is telocentric?
Centromere at very end of chromosome
How are the 2 arms of a chromosome identified?
Top arm above centromere is p arm, bottom is q arm
What is a chromosome abnormality?
Visible alterations of chromosomes produced by chromosome specific mechanisms
What are the different types of chromosome abnormalities?
Constitutional changes - All cells/tissues have same abnormality
Somatic changes - In any cell except sex cells eg skin cancer (not genetic)
Numerical changes
Structural changes
What is ploidy?
The number of chromosomes in a cell eg 1 set - Haploid, 2 sets - Diploid
Describe diploid cells
Contain 2 complete sets of chromosomes
Reproduce by mitosis forming exactly identical daughter cells
Skin, blood, muscle cells
Describe haploid cells
Half the number of chromosomes as diploid, 1 complete set
Formed from meiosis
Used in sexual reproduction
Describe polyploidy
Multiple sets of chromosomes
Common in plants, rare in animals
Occurs in humans, pathological and leads to death
