Meiosis

Description

A Levels Biology Mind Map on Meiosis, created by E P on 20/04/2015.
E P
Mind Map by E P, updated more than 1 year ago
E P
Created by E P over 9 years ago
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Resource summary

Meiosis
  1. Prophase 1
    1. Chromatin condenses and supercoils
      1. Homologous pairs come together to form a bivalent
        1. The non-sister chromatids wrap around each other at the chiasmata
          1. Swap sections of chromatids (crossing over)
          2. Nucleolus disappear and the nuclear envelope disintegrates
            1. Spindle forms, this is made of microtubules
          3. Metaphase 1
            1. Bivalents line up across the equator
              1. Spindle fibres attach to centromeres
                1. Bivalents are randomly assorted
                2. Anaphase 1
                  1. The homologous chromosomes in each bivalent are pulled by the spindle fibres to opposite poles
                    1. Centromeres do NOT divide
                      1. Chiasmata separate and lengths of the chromatid that have been crossed over remain with the chromatid
                      2. Telophase 1
                        1. Two new nuclear envelopes form, one around each set of chromosomes at each pole
                          1. Cell divides by cytokinesis
                          2. Chromosomes uncoil
                          3. Prophase 2
                            1. Nuclear envelope breaks down
                              1. Nucleolus disappears
                                1. Chromosomes condense
                                  1. Spindle fibres form
                                  2. Metaphase 2
                                    1. The chromosomes line up at the equator of the spindle attaching by the centromeres
                                      1. The chromatids are randomly assorted
                                      2. Anaphase 2
                                        1. The centromeres divide and the chromatids are pulled to the opposite poles by the spindle fibres
                                          1. The chromatids randomly segregate
                                          2. Telophase 2
                                            1. Nuclear envelope reforms around the haploid daughter cells
                                              1. In animals the two cells now divide to give 4 haploid cells
                                              2. IPMAT- Interphase, Prophase, Metaphase, Anaphase and Telophase
                                                1. Prophase- Preparation
                                                  1. Metaphase- meet in the Middle
                                                    1. Anaphase- When the chromatids are pulled they give an A shape
                                                      1. Telophase- Two new nuclear envelopes
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