Sunday, June 04, 2006

Meiosis demystified: Part 3

Microscope slides:
Stages of meiosis in an animal cell
Locust (x 350)
-


Interphase nucleus (not part of meiosis)



Meiosis I
Early prophase I
: chromosomes condensing and becoming visible


Prophase I: homologous chromosomes have paired up, forming bivalents, and crossing over or chromatis is ocurring; members of each pair of chromosomes are repelling each other but are held at the crossing-over points (chiasmata, plural of chiasma)

Metaphase I: bivalents line up across the equator of the spindle; the spindle is not visible in the photo

Anaphase I: homologous chromosomes move to opposite poles of the spindle

Telophase I and cytokinesis



Meiosis II
Metaphase II: single chromosomes line up across the equator of a new spindle

Anaphase II: chromatids separate and move to opposite poles of the new spindle

Late anaphase II

Telophase II



From Biology 2, Cambridge Advanced Sciences

1 Comments:

Blogger Zilko said...

Hi... :) I know about meiosis, I got that from school (biology class... :D).

2:43 pm, June 04, 2006  

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