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a. Resembles mitosis
i. preceded by__
What is difference?
duplication of chromosomes
- a. that it is followed by two divisions, meiosis I and IIà 4 daughter cells, each with half as many chromosomes as parent cell
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a. Stage Overview
i. Both members of __ are duplicated and copies are sorted into __
1. __ make up one duplicated chromosome, but the two chromosomes of a __ are individual chromosomes inherited from different parents
a. __appear alike, but differ in versions of genes, called __, at corresponding __
i. Only involved in meiosis
- homologous pair
- four haploid daughter cells
- Sister chromatids
- homologous pair
- Homologs
- alleles
- loci
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Meiosis does what?
i. Meiosis halves total number of chromosomes form two to one; each daughter cell receives one set of chromosomes
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Stages
- Prophase I
- Metaphase I
- Anaphase I
- Telophase I and Cytokinesis
- Interkinesis
- Prophase II
- Metaphase II
- Anaphase II
- Telophase II and Cytokinesis
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i. Prophase I
1. Chromosomes __; __loosely pair along __; aligned gene by gene
2. Paired homologs become physically connected to each other along their lengths by protein structures, called the __; this state is called __
3. __ , a genetic rearrangement between __involving __, begins during the __and __; completed while homologs are in __
condense
- homologs
- lengths
- synaptonemal complex
- synapsis
- Crossing over
- nonsister chromatids
- exchange of segments of DNA molecules
- pairing
- synaptonemal complex formation
- synapsis
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Prophase I cont.
1. __(3)__ occur as in mitosis
2. Late prophase I: microtubules from one pole or the other attach to two __, protein structures at the centromeres of the two __
a. Homologous pairs move towards __
- Centrosome movement, spindle formation, and nuclear envelope breakdown kinetochores
- homologs
- metaphase plate
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i. Metaphase I
1. Pairs of homologous chromosomes arranged at __, with one chromosome in each pair facing each pole
2. Both __of one homolog attached to __form one pole; those of the other homolog are attached to microtubules from the opposite pole
- metaphase plate
- chromatids
- microtubules
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i. Anaphase I
1. Breakdown of proteins responsible for __ along chromatid arms allow __ to separate
2. __move towards opposite poles, guided by __
3. __ persists at __, causing chromatids to move as a unit toward the same pole
- sister chromatid cohesion
- homologs
- Homologs
- spindle apparatus
- Sister chromatid cohesion
- centromere
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i. Telophase I and Cytokinesis
1. Beginning of Telophase I: each half of cell has complete __set of duplicated chromosomes
a. Each chromosome composed of two __; one or both chromatids include __
2. __occurs simultaneously, forming two __ daughter cells
a. Animal cells: __
b. Plant cells: __c. Some species: chromosomes condense and nuclear envelopes form
d. No chromosome duplication occurs between meiosis I and meiosis II: __
- haploid
- sister chromatids
- nonsister chromatid DNA
- Cytokinesis
- haploid
- cleavage furrow
- cell plate
- interkineses
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ii. Prophase II
1. __ forms
2. In late prophase II, chromosomes still composed of two __associated at __move toward __
- Spindle apparatus
- chromatids
- centromere
- metaphase II plate
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i. Metaphase II
1. Chromosomes on __
2. Because of __ in meiosis I, two sister chromatids are not __
3. __of sister chromatids attached to __extending from opposite poles
- metaphase plate
- crossing over
- genetically identical
- Kinetochores
- microtubules
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i. Anaphase II
1. Breakdown of proteins holding the sister chromatids together at __allows chromatids to separate
a. __move toward opposite poles as individual chromosomes
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i. Telophase II and Cytokinesis
1. __form, the chromosomes begin decondensing
2. __occurs
3. Meiotic division of one parent cell produces __daughter cells, each with a haploid set of unduplicated chromosomes
4. Four daughters genetically __from each other and parent cell
- Nuclei
- Cytokinesis
- four
- distinct
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