QUIZ 4.2 Flashcards
Sex cells or gametes are produced from ____ division.
meiotic
Meiotic Division and its functions
● production of functional sex cells or gametes
● two rounds: meiosis I and meiosis II
● reduction in the chromosome number
● allows restoration of original chromosome number during fertilization
_____ involves two rounds of cytokinesis which will ultimately produce four daughter cells with a reduced chromosome number.
Meiosis
comes after the G2 phase of the cell cycle.
Meiosis I
● Condensation
● Synapsis
● Crossing over
Prophase 1
site of crossing over between homologous pairs we have the
Chiasma
Pairs of chromosome are called _____
homologous chromosomes
● meiotic spindle formation
● further chromosomal condensation
● further disintegration of nuclear envelope
Prometaphase 1
● alignment of the homologous chromosomes at metaphase plate
● Maternal and paternal chromosomes are randomly arranged
● facilitates reduction in chromosome number
Metaphase 1
● separation of the homologous pairs (sister cromatids)
● Maternal and paternal members move to either pole
Anaphase 1
● the cytoplasm divides
● Chromosomes reach opposite poles.
Telophase I and Cytokinesis
is a REDUCTIONAL division.
Meiosis I
Is an EQUATIONAL division
Meiosis II
● Preceded by an interkinesis, chromosomes recondense
● new spindle forms around the chromosomes
Prophase II
● Disintegration of the nuclear envelope
Prometaphase II
● alignment of the duplicated chromosomes
Metaphase II
● seperation of sister chromatids
Anaphase II
nuclear envelope forms around each set of chromosomes
Telophase II and Cytokinesis
___ Formed by synapsis of homologous chromosomes
tetrad
maintains an identical set of genetic material in the daughter cells
Mitosis
___ reduces this amount and introduces new combinations.
meiosis
Synapsis occurs only in meiosis ___.
I
Tetrads line up and separate into individual homologous chromosomes in meiosis ___
I
Sister chromatids line up and separate into individual chromosomes in meiosis ___.
II
Crossing over occurs only in meiosis ___
I
Importance of crossing over (FIE)
● facilitates genetic recombination
● increases chances of survival
● enhances genetic variation
This event refers to the exchange of segments of the homologous chromosomes during meiosis I.
Crossing over
involves the pairing of the members of homologous chromosomes so as to allow them to undergo crossing over and to segregate them.
Synapsis
is considered the reductional division in meiosis because it reduces the number of sets of chromosomes from two to one
Meiosis I
by contrast, is considered the equational division in meiosis because there is no further reduction of the chromosome number in daughter cells.
Meiosis II
