Studied by 26 peoplemeiosis is a form of cell division that ------- the number of chromosomes when forming specialized reproductive cells or spores
halves
sperm or egg cells are examples of…
gametes
plants and fungi are examples of…
spores
what are the 2 forms of nuclear division?
meiosis I and meiosis II
DNA in the original cell is replicated once during….
interphase
meiosis begins with
homologous chromosomes pairing up
what are chromosomes that are alike in size, shape, and genes. one homologue from each parent in a cell
homologous chromosomes
in prophase I, loose ------ coils up into visible chromosomes (replicated chromosomes)
chromatin
when homologous chromosomes pair it is called
synapsis
what is the exchange of genes between a chromatid on one homologous chromosome and another chromatid of the other homologous chromosome
crossing over
what is the result of crossing over
genetic recombination
what is genetic recombination
new gene combinations
what is a group of 2 homologous chromosomes (4 chromatids)
tetrad
in prophase I, ------ form
tetrads
in prophase I, ------- breaks down
nuclear envelope
in prophase I, ----- disappears
nucleolus
in prophase I, ------- forms
spindle
in metaphase I, ------- line up along the equator with the help of ------- fibers
tetrads, kinetochore
in metaphase I, where does kinetochore fiber attachment occur?
on each side of a tetrad
in anaphase I, ---------- pairs seperate toward opposite poles of the cell (------- splits)
homologous chromosomes, tetrad
each homologous chromosome still contains…..
2 sister chromatids
do centromeres divide in anaphase I?
no
in telophase I, ----------- gather at the poles.
individual replicated chromosomes
--------- divides the original cell into 2 cells
cytokinesis
each daughter cell is ---------- because it only contains one chromosome from each pair of homologous chromosomes
haploid
do chromosomes replicate between meiosis I and meiosis II?
no
in prophase II, chromosomes ------ only if they uncoil between meiosis I and meiosis II
recoil
in prophase II, new ----- forms around the chromosome in both cells.
spindle
in metaphase II, ------- chromosomes (not tetrads) align at the equator of both cells.
individual
in metaphase II, each chromosome still contains - sister chromatids
2
in anaphase II, ------ divide and ------ chromatids seperate
centromeres, sister
in anaphase II, sister chromatids are now called -------.
individual chromosomes
in telophase II, ----------- reforms around chromosomes
nuclear envelope
in telophase II, ------- reappears in each nuclei
nucleolus
in telophase II, -------- dissolves
spindle
in telophase II, chromosomes uncoil into ------
chromatin
cytokinesis occurs resulting in - total new cells. each is ------ and unique
4, haploid
n + 1 or n - 1 is an example of a….
bad gamete
formation of gametes
gametogenesis
formation of sperm via meiosis in male animal testes
spermatogenesis
creation of a ovum (egg) during meiosis in female ovary
oogenesis
random distribution of homologous chromosomes during meiosis (metaphase I)
independent assortment
in humans, - million gametes with different gene combinations could result
8
other than independent assortment, what are 3 other mechanisms that contribute to genetic variation?
crossing over, random fertilization, and mutations
in ---------- each pair of chromosomes sorts its maternal and paternal homologoues into daughter cells independently of the other pairs
independent assortment
the process of producing offspring
reproduction
produces recombinant chromosomes that carry genes derived from two different parents
crossing over
in asexual reproduction, - parent passes all of its genes to its offspring.
1
in asexual reproduction, their is no fusion of -------- cells
haploid
asexual reproduction produces ------
clones
organisms that are genetically identical to its parent
clones
how do prokaryotes produce asexually
binary fission
how do eukaryotes produce asexually
mitosis
an advantage of -------- reproduction is that it produces many offspring in short time, no need to find a mate or produce gametes
asexual
a disadvantage of ---------- reproduction is that DNA stays the same, not good in a changing enviroment
asexual
separation of a parent into 2 or more individuals of about equal size
fission
what is an example of fission
bacteria
body breaks into several pieces, developing into complete adults
framentation
what is an example of fragmentation
planarian
new individuals split off from existing ones, bud may break off or remain attached.
budding
what are examples of budding
hydra and sponges
fission, fragmentation, and budding are all examples of -------- reproduction
asexual
in sexual reproduction, - parents are present
2
in sexual reproduction, their is fusion of --------
haploid gametes
in sexual reproduction, offspring have traits of both parents, but are not --------- to either parent,
identical
--------- reproduce sexually
eukaryotes
an advantage of ------ reproduction is that they have genetic variation
sexual
------------ is key to evolution
genetic variation
Note 
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