Download Meiosis Vocabulary Flash Cards Meiosis Haploid Cells Gamete

3/15/2011
Union of two parent sex-cells to form 1 new offspring cell.
Meiosis Vocabulary Flash Cards
• Chapter 9.5 and 9.6.
• Pages 192-201
New offspring cell proceeds with the Cell Cycle.
Interphase and Mitotic Phase to produce identical cells.
Specialized body cells begin to form and combine into tissue, organs
and organ systems to create a fully developed organism
The organism matures to an age
when sexual reproduction is possible
in specialized organs.
Many non-sex cells will
continue to be reproduced
through Mitosis as part of
the Cell Cycle.
The organism will continue to grow,
develop and survive as these cells
continue to be reproduced.
Meiosis
• Only occurs to produce cells responsible for
passing on inheritance (sex-cells).
• These cells develop when an organism has
sexually matured.
• These sex-cells carry only half of the number of
chromosomes originally inherited from parents.
(Haploid)
• All other cells in the body keep all inherited
number of chromosomes (Diploid).
Only specialized sex-cells
will begin to be produced
through Meiosis as part of
the Cell Cycle.
The organism will be capable of passing
on various combinations of genetic
material in these reproductive cells.
Haploid Cells
• Sex-cells responsible for passing on inheritance
• Contains only ½ the number of chromosomes
originally inherited.
• Sexual Reproduction: 2 haploid cells join to form 1
offspring cell, now with diploid number of
chromosomes.
• n = 1 set of chromosomes (humans = 23). One set
provided by a parent cell. Will match up with
homologous (similar) chromosomes of the other
parent cell involved.
Gamete Cells
Zygote Cell
• Sex-cells known as sperm and egg.
• Haploid number of chromosomes (1 set).
Gametes are the only haploid cells of an
organism.
• Gamete of father (sperm) will combine with
gamete of mother (egg) to form a diploid zygote
offspring.
• The cell that is created from the joining of a
sperm cell and egg cell.
• Contains 1 set of chromosomes from each
parent. Each set is homologous (similar) to the
other.
• Zygote will go through mitosis to create all body
cells of an organism forming into tissue, organs,
and organ systems.
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Diploid Cells
• Original zygote cell and all body cells.
• Contain total number of chromosomes inherited
from 2 original parent cells.
• 2n = 2 sets of chromosomes (humans = 46).
One set from a parent will match up with the
other parent’s homologous chromosomes.
Tetrad (set of 4)
• Duplicated sets of homologous chromosomes.
• During Interphase of cells within the sex
organs, the homologous chromosomes from
each parent will duplicate during S phase.
• This creates enough genetic material to
eventually form into 4 haploid sex-cells.
Homologous Chromosomes
• The chromosomes inherited from two parents
have similar genes.
• Ex: A chromosome from the father that
contains the gene for eye color will match up
with the same type of chromosome from the
mother. This occurs in the nucleus.
Crossing over
• Involves homologous chromosome tetrads in a sexcell.
• Genes from homologous chromosomes will be traded
or mixed.
• This creates new, unique versions of chromosomes
known as genetic recombination.
• These new chromosomes still have inherited genes,
but in a different arrangement.
• The eventual separation of homologous chromosomes
into 4 new sex-cells will cause the next offspring to
have a unique arrangement of characterisics.
Genetic Recombination
• Results from the crossing over of genes
between homologous chromosomes inherited
from parents.
• 1 sex-cell will be divided into 4 new gametes.
• Each gamete will have a rearrangement or
(recombination) of genes.
• Recombination of original genetic material
causes the offspring to be unique, but still show
characteristics of parents.
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