Meiosis Flashcards
decscribe the 3 steps of meiosis (b4, during, at end)
b4: one round of DNA duplication (same as B4 mitosis)
during: 2 rounds of chromosome segregation - Meiosis 1, Meiosis 2
At end: 4 daughter cells (haploid)
What are the differences found in meiosis 1 in comparison to mitosis?
prophase 1 : bivalent, crossing over of chromosomes
Metaphase 1 : bivalents formed
Anaphase 1 : homologous chromosomes are segregated towards spindle poles –not sis chromatids, independent assortment
Telophase 1: every homologous chromosome get separated into 2 poles of the cells and there’s reformation of nucleus.
define independent assortment
where random chromosomes segregate into the daughter cells
define bivalent
homologous chromosomes pair up
Describe the differences found in meiosis 2 in comparison to mitosis (5 points)
starts with diploid mother cell
Prophase 2 - each daughter cell receives one random homologous chromosome
metaphase 2 - organisation of chromosomes into metaphase plate
anaphase 2 - sis chromatids divide
telophase 2 - daughter cell receives 23 sis chromatids (some from dad and mum)
what are the two important characteristics found in meiosis
- crossing over forming bivalent
- indepen. assortment
how many rounds of:
chromosome duplication
chromosome segregation
one
two
define meiosis
process needed to create gametes, special cells with half the genetic info i.e. haploid needed for sexual reprod.
at what stage does meiosis occurs
before 1 round of DNA duplication
how can meiosis be divided
meiosis 1 and meiosis 2
define net result
from 1 diploid mother cell into 4 haploid daughter cells with half the genetic info, none is genetically identical.
define fertilisation
fusion of male and female gametes to reset the diploid asset of genetic info
