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Meiosis Notes:
Each organism must inherit a single copy of every gene from each of its
_______________. (Humans = _______ chromosomes)
_______________ (sex cells) are formed by a process that _____________ the
two sets of genes so that each ______________ends up with just one set. (____
splits to _____)
Chromosome Number
All organisms have different numbers of ___________________.
A body cell in an adult fruit fly has _____ chromosomes: _____from the fruit fly's
male parent, and ______from its female parent.
These two sets of chromosomes are ____________________. (homo = _______)
Each of the 4 chromosomes that came from the male parent has a corresponding
chromosome from the female parent. (#3 from ________, #3 from _______)
A cell that contains _________ sets of homologous chromosomes is said to be
______________. (di = ____)
The number of chromosomes in a ________________ cell is sometimes
represented by the symbol ________.
For Drosophila, the diploid number is 8, which can be written as __________.
(which means N =?)
The ______________ of sexually reproducing organisms contain only a ________
set of chromosomes, and therefore only a single set of genes.
These cells are _____________. _____________ cells are represented by the
symbol ______.
For Drosophila, the haploid number is ________, which can be written as N=___.
2(4) = 8
Meiosis is a process of __________________________ in which the number of
chromosomes per cell is cut in ___________ through the separation of
___________________ chromosomes in a ______________ cell.
Meiosis involves ________ divisions, _____________ and ________________.
By the end of meiosis II, the original ________________ cell that began meiosis
has become ____ ______________ cells.
____ _____________ cell becomes ____ ______________ cells
Phases of Meiosis
: Cells undergo a round of __________________, forming
duplicate chromosomes.
_________________ I:
Each chromosome pairs with its corresponding ___________________
chromosome to form a __________________.
There are 4 ________________ in a ____________.
Draw a Tetrad:
When ________________ chromosomes form _______________ in meiosis ___,
they exchange portions of their chromatids in a process called ______________ ___________.
____________-_______ produces new combinations of alleles. (brown hair- blue
eyes, brown hair - brown eyes)
_____________ I:
Spindle fibers attach to the ______________________.
Tetrads line up in ________________.
_____________ I:
The fibers pull the ________________ chromosomes toward opposite ends of the
cell. (__________)
__________________ I and Cytokinesis:
__________________membranes form.
The cell separates into _________ cells.
The two cells produced by meiosis I are __________________ to each other or the
_______________ cell.
Meiosis II
The two cells produced by meiosis I now enter a second ____________ division.
(meiosis II)
Unlike meiosis I, chromosomes ____________ replicate.
Each of the cell’s chromosomes has 2 _______________ only.
__________________ II:
Meiosis I results in two _______________ cells, which will both enter Meiosis II.
_________________ II:
The chromosomes line up in the ____________of cell.
_________________ II:
The ____________________ separate and move toward opposite ends of the cell.
Telophase II and ____________________:
Meiosis II results in __________ haploid (____) daughter cells.
Gamete Formation
In ___________ animals, meiosis results in four equal-sized gametes called
____________.
In many _____________ animals, only __________egg results from meiosis. The
other three cells, called _________________, are usually not involved in
reproduction.
Comparing Mitosis and Meiosis
Mitosis results in the production of ____ genetically identical ________cells.
Meiosis produces ________ genetically different _________ cells.