Mitosis and Meiosis Flashcards
What is the Cell Theory?
Cells are the fundamental units of all living organisms
What is mitosis?
division of a parent somatic cell into 2 genetically identical daughter cells/ progeny. (asexual reproduction)
(more complex in eukaryotic than prokaryotic cells- binary fission)
What are 2 stages of mitosis?
- Interphase
- Cell growth and development (G1/G0)
- the cell is preparing for division (S/G2)
- period between cell divisions
- M-phase (Mitotic phase)
-period of active cell division- firstly nuclear division or mitosis occurs
- followed by cytokinesis or cytoplasmic division
What are the phases of mitosis?
PMAT =>
Prophase
Metaphase
Anaphase
Telophase and Cytokinesis
What is meiosis?
division of parent germ cell into four genetically variable daughter cells/ progeny
What are the phases of meiosis?
Meiosis I
*Prophase I (Leptotene- this threads, Zygotene- homologous chromosomes, Pachytene- thick threads/ crossing over at synapse, Diplotene- two threads still attached at chiasmata, Diakinesis- break down of membrane and spindle fibres form)
*Metaphase I (Homologous Chromosomes align- random assortment)
*Anaphase I
*Telophase I (and Cytokinesis)
Meiosis II
*Prophase II
*Metaphase II
*Anaphase II
*Telophase II (and Cytokinesis)
What accounts for genetic variation?
- Mutation (both mitosis and meiosis)
- Creates novel alleles (point mutation)
- Polyploids (chromosomal aberrations)
- Recombination (only in meiosis)
- Shuffles existing alleles to create novel allelic combos