W1LAB - Genetic aspects of atypical mitosis and meiosis Flashcards
What are the phases of cell cycle?
Interphase: G1, S, G2
Prophase
Metaphase
Anaphase
Telophase
What are the phases of typical mitosis?
Give the structure of chromosome
Give the number of DNA content and chromosomal number of this haploid cell through each phase
Describe the Structure of mitotic spindle
What are the 7 types of mitosis?
- Typical
- Atypical
- Endomitosis (endoreduplication)
- No cytokinesis
- Multipolar division
- Bridge formation
- Non-disjunction
What are the consequences of typical and atypical types of mitosis?
- Typical -> Genetically identical cells.
- Atypical -> Genetically not identical cells (In multicellular organism causes mosaicism)
What is the description of Endomitosis (Endoreduplication)?
DNA is duplicated, but during M-phase the nuclear envelope remains intact.
1) No separation of chromatids
2) Separation of chromatids
What are the consequences of Endomitosis (Endoreduplication)?
- Giant cell, giant nucleus
- Polythene (giant) chromosomes (if there is No separation of chromatids)
- More chromosomes (polyploid cell) <- if there is Separation of chromatids
What is this?
Polythene (giant) chromosomes
-> consequence of endomitosis
What is this?
giant cell derived by endomitosis
(a consequence of Endomitosis)
What are the consequence and description of mitosis which has no cytokinesis?
- Description: Mitosis is not followed by cytokinesis.
- Consequence: Multinucleated (giant) cells.
What are the consequence and description of mitosis which has Multipolar division?
- Description: Due to atypical duplication and division of centrosome chromosomes are pulled to more than two poles
- Consequence: abnormal chromosome number
in the arising cells.
What is this?
Tripolar metaphase
What is this?
Tripolar metaphase
What are the 3 consequences of mitotic spindle errors?
- Anaphase-lag
- Non-disjunction
- Bridge formation
What is the consequence of bridge formation?
Acentric fragment
-> Cause micronucleis
What are the consequence and description of mitosis which has Bridge formation?
- Description: A chromatid is pulled from two poles.
- Consequence: Breakage of chromosome (structural chromosomal aberration)
What are the consequence and description of mitosis which has Mitotic Non-disjunction?
- Description: Lack of kinetochor microtubules attachment to a chromatid.
- Consequence: abnormal chromosome number
What is the result of meiosis?
4 genetically different haploid cells
What are the essentials of meiosis?
- Two divisions – meiosis I and II
- Chromosome number is halved
- Genetic variability – homologous recombination - independent assortment of chromosomes
=> synapsis
Give the numbers of DNA content and chromosome number of this cell?
What is the cause of aneuploid genom mutations?
Meiotic nondisjunction
Describe Meiotic non-disjunction
- Results of meiotic I and meiotic II non-disjunction are different
- Meiotic non-disjunction may occur both in oogenesis and spermatogenesis BUT MORE FREQUENT IN OOGENESIS
- Sex chromosome non-disjunction is more frequent in spermatogenesis
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = early prophase
2 = metaphase (side view).
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = metaphase (from above)
2 = metaphase (side view).
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = telophase
3 = metaphase (side view)
4 = telophase
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = anaphase.
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = multinucleated cells
2 = nucleus with many nucleoli
3 = cytoplasm.
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = giant cell derived by endomitosis
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = anaphase bridge
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = tetrapolar mitosis, metaphase
2 = nucleus
3 = cytoplasm (binucleated cell)
Typical and atypical mitotic phases in cell culture
52. HeLa monolayer (MGG)
-> Identify
1 = metaphase
2 = tripolar metaphase
3 = acentric fragment
4 = cytoplasm
5 = interphase nucleus with nucleoli.
Give Number of DNA molecules in one cell
Give the Number of chromosomes in one cell
Give the Number of chromatids in chromosome
Give the number of Ploidy
What is true for the ploidy during meiosis I.?
