2P: Typical and atypical mitosis Flashcards
G2-M transition influenced by
Cell size, DNA damage, DNA replication
Metaphase-anaphase transition influenced by
Chromosome attachments to spindle
Restriction point influenced by
Growth factors, nutrients, cell size, DNA damage
Three types of mitotic spindle
- Astral MT (at poles around centrosome)
- Kinetochor MT (attaching to centromere)
- Polar MT
In atypical mitosis the result is
Not genetically identical cells (causes mosaicism in multicellular organisms)
Result of typical mitosis
Genetically identical cells
What is endomitosis?
DNA duplication where nuclear envelope remains intact during M-phase
Result of endomitosis
Giant cell, giant nucleus
- No sep. of chromatids -> polythene (giant) chromosomes
- Sep. of chromatids -> More chromosomes (polypoid cell)
What is the result of no cytokinesis in mitosis?
Multinucleated (giant) cells
What is multipolar division?
Atypical duplication and division of centrosome causes chromosomes to be pulled to more than two poles
Result of multipolar division
Abnormal chromosome number in the arising cells
What is bridge formation?
A chromatid is pulled from two poles
Result of bridge formation
Breakage of chromosome (structural chromosomal aberration)
What is non-disjunction?
Lack of kinetochore microtubule attachment to a chromatid
Result of non-disjunction
Abnormal chromosome number
