Download 11-13-12 Meiosis FILL IN THE BLANK NOTES

Meiosis

Is a form of __________________ that _______________the number of chromosomes when
forming specialized ___________________________________(gametes).

Meiosis involves _______ divisions of the nucleus – meiosis I and Meiosis II

Starts with_________________________, and ends with______________________________.

Review of Terms

Haploid (n)--

Diploid (2n)--

_____________________ – Two exact copies of DNA (each single copy called a chromatid)
makes up a ______________________.

_____________________ – point at which the two chromatids are ____________.

________________chromosomes – chromosomes ___________in size, shape, and genetic
content.
Meiosis I
During Prophase I…


Homologous Chromosomes ________________ (pair together)
This group of 2 chromosomes together is called a _________________________ (because there
are 4 chromatids)

_________________________ occurs
Crossing – over occurs when portions on one homologous chromosome are
_________________________________with the corresponding portion on one of the
_________________ of the other homologous chromosome.
Metaphase I

Paired Homologous Chromosomes line up in the ____________________ of the cell.
Anaphase I


Paired Homologous Chromosomes _______________________
Daughter Cells are now _____________________________
Telophase I

_________________________________ forms around each set of chromosomes

__________________________ begins -division of __________________________

Left with...

Between Meiosis I & II …
Meiosis II – SAME AS MITOSIS
Prophase II, Metaphase II, Anaphase II , Telophase II

Prophase II

A new spindle forms around the chromosomes
________________– are cell structures made up of both centrioles and individual microtubule fibers
that are involved in _________________________________________________________________.
___________________- two cylindrical cellular structures that form at the poles of a cell during meiosis.


Metaphase II
Chromosomes line up in the ______________________ of the cell

Anaphase II

_________________________ divide

Chromatids move __________________________ of the cell
* Remember centromeres are what ______________________________________________to make a
chromosome.

Telophase II

_________________________________forms around each set of chromosomes

____________________________ begins

Left with...
Karyotype

Ordered display if an individual’s chromosomes arranged in pairs, starting with the longest.
Trisomy 21

Three number 21 chromosomes, making 47 total. Causes
____________________________________________.
Errors

_____________________________________– a member of a chromosome pair fail to separate.

_____________________________________– a fragment of a chromosome is lost.

_____________________________________ – a fragment of one chromosome joins to a sister
chromatid.

_______________________________ _____– a fragment reattaches to the original
chromosome, but in the reverse direction.

_______________________ _____________– a fragment attaches to a nonhomologous
chromosome.