Topic 4-2 Flashcards
what is the purpose of meiosis?
to produce gametes for sexual reproduction
most _______ cells are diploid cells
eukaryotic
why is it necessary to reduce the number of chormosomes in each cell during meiosis?
so that you don’t double the number of chromosomes with each generation
a mature haploid male or female germ cell
gametes
what are the three main stages of the cell cycle in a meiotic cell?
- interphase
- meiosis I
- meiosis II
meiosis I is known as the __________ division phase
reductional
meiosis II is known as the _________ division phase
equatorial
during late prophase I, homologous chromosomes pair up and DNA arms ‘crossover’, forming:
chiasmata
what is the chiasmata?
the location at which the chromosome arms link to exchange genetic info
the close pairing of homologous chromosomes during meiosis I
synapsis
closely associated four sister chromatids of two homologous chromosomes
tetrad
why does “crossing over” occur during meiosis I
helpful for generating genetic variation in newly formed gametes
what is interkinesis?
interphase II, a period of rest between telophase I and prophase II
unlike mitosis, the daughter cells in meiosis are:
genetically variable
what is the purpose of the cohesin rings around the chiasmata?
hold homologous pairs of chromosomes together
what is the purpose of the cohesin rings around the centromeres?
hold sister chromatids together
the protein that protects the sister chromatid cohesin
shugoshin
what is the main purpose of shugoshin?
prevents the separation of sister chromatids during anaphase I
what are the three genetic consequences of meiosis?
1) results in 4 daughter cells that are genetically variable
2) results in 4 daughter cells that hav half the number of chromosomes
3) daughter cells contain about half of the cytoplasm and half of the organelles
