Studied by 16 peopleWhat kind of reproduction does meiosis occur in?
Sexual reproduction
Advantages of asexual reproduction
It is faster.
2)Large numbers are produced
3)the parent doesn’t need a mate
Disadvantages of asexual reproduction
offspring are all alike
the ability to adapt to a changing environment
advantage of sexual reproduction
all offspring are different
disadvantages of sexual reproduction
the parent must find a mate
2)fewer are produced
3)it takes longer
scientific term for sex cells
gametes
scientific term for a fertilized egg
zygote
union of sperm and egg
fertilization
How many sets of chromosomes will an offspring of sexual reproduction have
2
homologous chromosome
two copies of each chromosome
Diploid
Two of each kind of chromosome
the symbol for diploid is 2N
egg and sperm must have ____ the number of chromosomes
half
1N+1N→
2N
What kind of cell are gamtes
haploid or 1N
How do egg and sperm cells become 1N
meiosis
Meiosis is a process of
reduction division in which the number of chromosomes per cell is cut in half
the chromosome replicate and 2 sister chromatids are held together by a centromere
interphase
Chromosomes form homologus pairs
prophase 1
tetrads line up at center of the cell
metaphase 1
the tetrads break apart and sister chromatids remain attatched at their centromeres
anaphase 1
The pairs of sister chromatids start to line up at middle of the cell
prophase 2
pairs of sister chromatids line up at the center of the cell
metaphase 2
pairs of sister chromatids separate
anaphase 2
results in four new 1N cells
Telophase 2 (and cytokenesis)
a tetrad consists of
4 chromatids
_________ is the exchange of genes between segments of homlogus chromosomes during meiosis
crossing over
Variation leads to
adaptation and change
crossing over leads to
evolution
meisosis produced
four haploid cells that are different
in females 4 cells are produced but only one will become an egg the other three cells will
never be functional
Note
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