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Unit 18 – Assignment 2 – P3
Mitosis stages:

Unit 18 – Assignment 2 – P2 & M2
Mitosis
Mitosis produces genetically identical cells
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The cells divide to
produce two new cells; each with an exact copy of the parents DNA
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It begins with a cell that has 2N chromosomes, but 4X DNA content because each
chromosome has replicated
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All eukaryotic cells replicate via mitosis, except for cells that produce gametes
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Interphase is the
metabolic phase of the cell
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It then
grows, reads its DNA, and then will carry out its cell functions
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After that, the nuclear envelope breaks down and the centriole divides into
two
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Metaphase: Then the chromosomes line up at the equator, then are attaches to the spindle by the
centromere
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The chromatids attach to the pole
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Once they are at the poles, they are called
chromosomes
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Then the spindles break
down
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Cytokinesis: The membrane divides the cells and the cell walls are formed in plants and fungi
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The chromosomes are indistinct chromatin
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Meiosis
Meiosis is the type of cell division where gametes are produced
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Meiosis produces haploid gametes from diploid cells
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2N chromosomes, 4N DNA content
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This results in 4 haploid gametes: 1N
chromosomes, 1X DNA content
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Metaphase 1: The nuclear membrane then disappears and then the microtubules from a spindle
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After that the two homologous
chromosome attach themselves to microtubules aligning from opposite poles
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Each pole then ends with a full haploid set of chromosomes
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Telophase 1: The nuclear membrane later reforms around the daughter nuclei
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They are attached to a common
centromere
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Metaphase 2: The nuclear envelope breaks down and a new spindle forms
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Anaphase 2: The spindle fibres contract and the sister chromatids move towards opposite poles
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Unit 18 – Assignment 2- P4
Independent Assortment of Chromosomes
As meiosis occurs, pairs of chromosomes will line up on the equator
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Alleles for a specific phenotype determines what characteristic an
organism will have
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Reference: http://www
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org/2/2_meiosis
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This is so that the gametes that it will produce will contain a mixture of alleles from both
parents
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There are many numbers of combinations that these alleles in the
gametes could produce
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This point of contact is called the chiasmata; it
allows the exchange of genetic information between chromosomes
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Prophase 1: Firstly, the DNA coils and then homologous chromosomes become joined together in
synapsis; they exchange sections by crossing over

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