{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 3 - Many se xually re producing organism alte s...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Many sexually reproducing organisms alternate between two states diploid haploid EUKARYOTIC CHROMOSOME : nucleus
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
HOMOLOGOUS CHROMOSOMES: NON-HOMOLOGOUS CHROMOSOMES: MITOSIS:
Background image of page 2
SISTER CHROMATIDS:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Sister chromatids are held together by protein complexes called cohesins that are loaded onto thechromosomes during replication. During prophase of mitosis, each pair of sister chromatids condenses to form a highly compact structurethat is easier to segregate. Kinetochoreor centromere
Background image of page 4
At Metaphase, sister chromatids arealigned with their kinetochores pointing to oppositepoles of thespindle
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
At Anaphase, thecohesin complexes aredestroyed and sister chromatids arepulled to oppositepoles. After cytokinesis, theresult is two genetically identical daughter cells!
Background image of page 6
MEIOSIS: Thechromosomenumber is divided by half during meiosis becausetherearetwo rounds of chromosomesegregation following a singleround of chromosome duplication. 2n premeiotic S 4n Meiosis I 2n Meiosis II n Humans 46 premeiotic S 92 Meiosis I 46 Meiosis II 23
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Prior to Meiosis I, chromosomeduplication creates sister chromatids connected by sister chromatid cohesion near the centromeres and thearms. 2n 4n Note that a single centromere functions for each pair of sister chromatids
Background image of page 8
During meiotic prophase, homologous chromosomes become physically associated by a combination of crossing over and sister chromatid cohesion. This connection allows homologs to align properly at Metaphase I.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}