Lecture 18: Meiosis Flashcards
inhibitors of microtubules
taxol, paclitaxel, nocodazole, vinblastine (all toxic )
inhibitors of microfilaments
cytochalasin, phallodin
steps of meiosis
Interphase (G1, S, G2), Prophase 1, Metaphase 1, Anaphase 1, Telophase 1 and Cytokinesis 1, Prophase 2, Metaphase 2, Anaphase 2, Telophase 2 and Cytokinesis 2
Meiosis I is like
the business side of meiosis (separating homologous chromosomes)
Meiosis II is like
mitosis (separating sister chromatids)
Prophase I (Meiosis)
Centrosome movement along with spindle fiber formation
- Nuclear envelope dissolves
- Chromosomes condense
- Homologous chromosomes pair up and cross over genetic material
- Microtubules attach to kinetochores of each homologous pair (move them to methaphase plate)
Metaphase I (Meiosis)
Tetrads are lined up (homologous chromosomes) at the metaphase plate; Spindle fibers attach
- independent assortment
Anaphase I (Meiosis)
Homologous chromosomes separate
Telophase I (Meiosis)
Cytoplasm divides, 2 daughter cells are formed (nucleus forms), chromosomes condense and nuclear envelope forms
Cytokinesis I
cell separates into two cells
Prophase II
spindle forms
Metaphase II
still 2 chromosomes, 2 chromatids align at metaphase plate
Anaphase II
splitting of chromatids (not sisters)
homologous chromosomes
same size, contain genes at same location in the chromosome
sister chromatids
replicated forms of a chromosome joined together by the centromere
synapsis
pairing of replicated homologous chromosomes during prophase I of meiosis
crossing over
exchange of genetic material between non-sister chromatids during synapsis in meiosis I
chiasma
area/region where crossing over occurs
mitosis vs meiosis similarities
both divide at the same time
the movement of chromosomes involves
microtubules
mitosis vs meiosis differences
synapsis only occurs in meiosis
purpose of meiosis
reproduction (gametes)
