Kategoriak: All - meiosis - chromosomes - nucleus

arabera Sok Lee 13 years ago

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Meiosis

Meiosis is a specialized type of cell division that results in four daughter cells, each with half the chromosome number of the parent cell. This process is essential for sexual reproduction and involves two sequential stages:

Meiosis

Meiosis

Reduction division

Products

Four daughter cells
half the chromosome number of parent cell
genetically different from parent cell

Process

Meiosis II
Teophase II

Nuclear envelope and nucleolus reform

Spindle disintegrates

Chromosome uncoil and become indistinct

Anaphase II

Chromotids become the chromosomes of the daughter cells

Chromatids are pulled to opposite poles

Centromeres divide

Metaphase II

Attachment of chromosomes to spindle fibre

Chromosomes arrange themselves at the equator

Prophase II

spindle fibers develop at right angles to the spindle axis of meiosis I

movement of centrioles to opposite poles

disintegration of nucleolus and nuclear envelope

Meiosis I
Telophase I

Each daughter nucleus has half the chromosome number as the parent nucleus.

Nuclear envelope surrounds each group of chromosomes

Spindle fibres disintegrate

Chromosomes reach opposite poles of the spindle

Anaphase I

Separation of homologous chromosomes

one of the pair pulled to one pole, and the other to the other pole

Metaphase I

Attachment of chromosomes to spindle fibers

arrangement of each bivalent is completely independent of the other.

bivalents arrange at the equator

Prophase I

Chiasmata observed

Homologous chromosomes pair up (synapsis)

Disintegration of nuclear envelope and nucleolus

Condensation of chromosomes