Prophase ​
Tags
Cegep1
Biology
Word count
113 words
Reading time
1 minute
First phase of mitosis and meiosis
Steps:
- Mitosis & prophase I: Chromatin fibres condense into discrete chromosomes
- Prophase I: homologous chromosomes form a pair called tetrad
- Prophase I: crossing over: homologous chromosomes exchange segments at chiasmata
- Basis of independent assortment
- Nucleoli disappear
- Microtubules from centrosomes lengthen to form the mitotic spindle
- Animal cells: centrosomes move apart to two poles
- Nuclear envelope fragments
- Microtubules attach to chromosomes by kinetochores
[!abstract] Mitotic spindle
Formation that grabs chromosomes and pulls them apart
Made of two centrosomes microtubules
[!abstract] Centrosome
T-shaped object that connects the microtubules
Made of a pair of centrioles
Ajitani Hifumi