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Cell Division

Cell Division. Mitosis vs. Meiosis Honors Biology Ch. 5 & Ch. 6-1, 6-2. Why do cells divide?. 1) ______________ : increase number of cells by cell division _________________________________; occurs via _________ 2) ______________ :

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Cell Division

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  1. Cell Division Mitosis vs. Meiosis Honors Biology Ch. 5 & Ch. 6-1, 6-2

  2. Why do cells divide? 1) ______________: • increase number of cells by cell division • _________________________________; occurs via _________ 2) ______________: • _________ reproduction = production of offspring from one parent (in ________); ____________ • _________ reproduction = formation of a new individual from union of 2 sex cells (fertilization of sperm and egg); occurs via ___________

  3. Cell Cycle • the sequence of cell growth and division that occurs in a cell (Interphase) ___ -> ___ -> ___ -> Mitosis/meiosis ____ = rapid growth ____ = DNA synthesis/replication ____ = centrioles replicate

  4. _________ is DNA wrapped around proteins called _________. A _________ has two sister _________ held together by a ___________. Chromtain, Chromatid, Chromsome

  5. 4 Phases of Mitosis • _________ - Chromosomes appear; nuclear membrane disappears; centrioles start migrating to opposite ends; spindle fibers start forming • _________ - Chromosomes line up on spindle fibers along the equator of the cell. • _________ - Centromeres split apart and sister chromatids separate. • _________ - Chromatids reach the opposite ends; chromosomes unwind; spindle breaks down; nuclear membrane reappears; _________ (splitting of cytoplasm);

  6. Phases of Mitosis Analogy Interphase (G1, S, G2) __________________ • Prophase (_________) • Metaphase (___________________) • Anaphase (_______________________) • Telophase (__________________)

  7. Difference between animal and plant cell division • Plant cell forms ______ (_____________ _____________________________) during ___________ whereas animal cell cytoplasm pinches in along the equator. • Plant cells DO NOT have _________.

  8. How is meiosis different from mitosis?

  9. Mitosis ________ reproduction _______cells (body cells) ___ division __ daughter cells formed Daughter cells are _________to parent cells Chromosome # is ___________(_______) No pairing of _________ chromosome No _______________. Meiosis ________ reproduction __________ cells (eggs & sperms = _________) ____ divisions __ daughter cells formed Daughter cells are _____________ identical to parent cells Chromosome # is _____ (________) Pairing of ___________ chromosome __________ btwn _________ chromosome may occur Mitosis vs. Meiosis

  10. Meiosis

  11. # of Chromosomes • Humans have ____ chromosomes in a body cell. ________ • Humans have ____ chromosomes in reproductive cells such as sperm or egg. ________

  12. Fertilization ________ sperm (___) + egg (___) _______ (a fertilized egg ) (___) -> embryo

  13. True or False • Mitosis occurs in sex cells and meiosis occurs in body cells. • Centrioles are involved in cell division in both plants and animals. • Each human body cell has 23 chromosomes. • Chromosomes are tightly coiled DNA. • Each chromosome has 2 sister chromatids.

  14. Homologous chromosomes • Each pair of _____________ chromosomes has genes for the ________ ( such as hair color/eye color) arranged in the _________. It may not be exactly identical though b/c of different __________ (forms of genes). • ___________ chromosomes may cross-over during the __________ of ________.

  15. Crossing Over(during _____________)

  16. Meiosis I ___________ chromosomes pair up and ___________ during ___________. ________________split. ___ lines Chromosomes # is ________. Meiosis II ___________ chromosomes do not line up. _______________ split. ___ line Similar to _______ Chromosome # stays as ________. How is Meiosis I different from Meiosis II?

  17. True or False • Homolgous chromosomes line up during the metaphase of mitosis. • Crossing over occurs between 2 sister chromatids. • In meiosis II, sister chromatids split, not homologous chromosomes. • Mitosis produces haploid cells and meiosis produces diploid cells. • Cytokinesis occurs during the anaphase of mitosis and meiosis.

  18. What is Cancer? • ____________ cell division caused by damage to ______ regulating the cell division cycle. • Types of Cancer • _______ - a sedentary mass of cancerous cells • ________ - a moving mass of cancerous cells metastasis

  19. Change in US Death Rates* from 1991 to 2006 Rate Per 100,000 1991 2006 * Age-adjusted to 2000 US standard population. Sources: US Mortality Data, National Center for Health Statistics, Centers for Disease Control and Prevention, 2009.

  20. Causes of Cancer • Carcinogenic chemicals, _______, ______ • Mechanism – ___________. • ________ agents cause mutations in genes that encode for proteins that regulate cell division and growth; cell growth is no longer under control.

  21. Non-disnjunction • chromosomes fail to separate during _________ (an error in ________) • Leads to genetic disorders such as ________, ________ and ________.

  22. Disorders caused by non-disjunction Ex: _________- one too few chromosomes -Turner Syndrome (XO) _________- one too many chromosomes -___________ (trisomy 21) -________________ (XXY)

  23. True or False • Cancer is caused by mutations in genes that control cell cycle. • Non-disjunction that occurs during mitosis affect the offspring. • Down syndrome is monosomy. • Turner syndrome is caused by non-disjunction.

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