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30 Cards in this Set
- Front
- Back
meiosis
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reductional division
-eukayotes -dip useful for backup copy of genes in mutation occurs |
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meiosis 1
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-reduction
- 2n-n -separate homo pairs |
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meiosis 2
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divides remaining set of chromosomes
-division -separate 2 chromatids |
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prophase 1
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-chromatid threads twist and condense (visible)
-chromo searches for homo chromo -chiasma -sometimes crossing over |
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chiasma
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point where 2 non sister chromos intertwine
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crossing over
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2 non sister chromatids exchange genetic material
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leptonema
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-chromos condense
-homo pair searching |
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zygonema
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-homo pairs find e/o- "rough pairing"
-synaptonemal complex |
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synaptonemal complex
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lateral elements that form bw 2 homo pairs during zygonema of prophase 1
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pachynema
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-coiling and shortening continues as chromos become more condense
-synapsis forms forming tetrad |
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diplonema
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-sister chromatids begin to separate
-crossing over occurs (actually occurs in pachynema) -chiasmata becomes visible |
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crossing over process
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-Homologues break at identical locations, then rejoin opposite partners.
-new combinations of the alleles on each chromosome. -Occurs randomly several times on every chromosome. -Results in mixing of the genes you inherited from your parents |
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Diakinesis
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-chromosomes continue to pull apart, but non-sister chromatids are still loosely associated via the chiasma.
-terminalization. -the nuclear envelope breaks down and the spindle fibers begin to interact with the tetrad. |
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terminalization.
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-The chiasma begin to move toward the ends of the tetrad as separation continues.
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synapsis
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-forms tetrad
-aligns homologs -shortens chromos |
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metaphase 1
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-pairing and separating of homo "C"
-tetrads align at metaphase plate -centromere of homo "C" oriented toward opp cell plates |
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anaphase 1
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-the pairs of homologues ‘C’ are pulled to opposite poles by the spindle.
-centromeres don't divide |
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telophase 1
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-each pole has hap # of "C"
-cytokinesis -2 daughter cells formed (half the number of "C" as original parent) |
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prophase 2
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-nuclear mem and nuclei break up
-spindle network appears and chromos begin to migrate |
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meta 2
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-"C" line up at equatorial plate
-kinetochore of sister chromatids point toward opp poles |
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anaphase 2
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sis chromatids sep
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telophase 2
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distinct nuclei at opposite poles and cytokinesis
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deletion
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-consequences depend on size of missing segments and which genes are found on it
-cri du chat syndrome |
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cri du chat syndrome
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partial deletion on short arm p of chromo 5
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Duplication
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-partial trisomy
-3 copies of genes= extra directions -congential abormalities or developmental problems |
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partial trisomy
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doubling of a chromosome
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inversion
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-"C" pieces broken out, reversed and inserted again
-phenotype=unobstructive -pericentric inversion or else paracentric inversion |
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pericentric inversion
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when interchanged region includes centromere
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insertion
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-"C"pieces reinseted somewhere else
-carriers= phenotypically inconspicuous because no info lost |
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Reciprocal Translocation
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-2 broken off "C" pieces of non- homo "C" are exchanged- frequent anomaly
-frequently balanced because entire genetic material is present - probs in gamete formation |