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2014

Výukový materiál MB 04 - 96 Tvůrce: Mgr. Šárka Vopěnková Tvůrce anglické verze: ThMgr. Ing. Jiří Foller Projekt: S anglickým jazykem do dalších předmětů Registrační číslo: CZ.1.07/1.1.36/03.0005 Tento projekt je spolufinancován ESF a SR ČR. 2014. CELL DIVISION - MEIOSIS.

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2014

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  1. Výukový materiál MB 04 - 96 Tvůrce: Mgr. Šárka Vopěnková Tvůrce anglické verze: ThMgr. Ing. Jiří Foller Projekt: S anglickým jazykem do dalších předmětů Registrační číslo: CZ.1.07/1.1.36/03.0005 Tento projekt je spolufinancován ESF a SR ČR 2014 CELL DIVISION - MEIOSIS

  2. sexual reproduction • sexual cells = gametes • gamete + gamete = zygote • zygote > germ > adult individual • gametes have got the half number of chromosomes • 46 chromosomes > 2 sets each of 23 chromosome • 2 sets of chromosomes = diploid cells • one set of chromosomes = haploid cells MEIOSIS

  3. meiosis completes a special type of cell cycle, by which gametes develop • meiosis = gametogenesis • interphase ( G1 , S phase a G2 phase) > meiosis: • only one replication of DNA in S phase • and two cell divisions followed quickly after each other • therefore - > originated cells are haploid • meiosis = reducing division MEIOSIS

  4. a) first meiotic division = heterotypical reducing: • different from mitosis • from 1 diploid cell develop 2 haploid cells • b) second meiotic division = homeotypical: • Identical with mitosis • from 2 haploid cells develop 4 haploid cells MEIOSIS

  5. a) first meiotic division = heterotypical reducing: • prophase: • conserved nucleolus and nuclear membrane • 2 sets of homological chromosomes • pair homological chromosomes attach to each other = synapsis ( „zip fastening“) • pairs of connected homological chromosomes are called bivalents MEIOSIS

  6. bivalents are four-thread formations= tetrads • recombination process – crossing – over: • reciprocal exchange of parts non-sister chromatids, which are not genetically identical • new combinations of gather and mother genes develop • synapsis ends by the isolation of homological chromosomes MEIOSIS

  7. metaphase: • equatorial plane • ! division of centromeres does not happen > neither chromosomes • anaphase: • reduction of the chromosome number > to the poles travel whole, not divided two-chromatid chromosomes • random segregation of father and mother chromosomes > various combinations in gametes MEIOSIS

  8. telophase ……… • b) second meiotic division= homeotypical: • normal mitosis 2 haploid cells • prophase, metaphase, anaphase, telophase • 4 haploid cells originate MEIOSIS

  9. 1) reduction of chromosome number • 2) recombination of father and mother genes by the process crossing – over • 3) random meiotic segregation • great genetic importance MEIOSIS - SIMMARY

  10. male (haploid) + female gamete (haploid) • = diploid zygote • by multiple division of the zygote ( = more mitosis) the whole organism develops • the most cells are diploid (multicellular organisms) • lower plants (non-vascular) + bacteria are haploid MEIOSIS

  11. diversification of cellsinto different types • all cells have the same, complete genetic base • they use only a part of the genetic information by their specialisation DIFFERENCIATION OF CELLS

  12. PROCESS OF MEIOSIS – A SCHEMA

  13. Genetic schema of miotic division of cell nucleus: a – e heterotypical prophase – • laptotene b) zygotene c) pachytene d) diplotene e) diakinesis • f) heterotypical metaphase (bivalents attached to the threads of division spindle) • g) heterotypical anaphase (bichromatide chromosomes from bivalents separate from each other • h) homeotypical prophase • Homeotypical metaphase j) homeotypical anaphase • j) (monochromatide daughter chromosomes go • to the poles of the division spindle)

  14. DESCRIBE THE PICTURE

  15. COMPARISON OF MITOSIS AND MEIOSIS

  16. MEIOSIS MITOSIS Meioza I COMPLETE INTO THE PICTURE Meio II.

  17. CHALUPOVÁ-KARLOVSKÁ, Vlastimila. Obecná biologie: středoškolská učebnice : evoluce, biologie buňky, genetika : s 558 řešenými testovými otázkami. 2., opr. vyd. Olomouc: Nakladatelství Olomouc, 2010, 206 s. ISBN 978-807-1822-820 • KUBIŠTA, Václav. Obecná biologie: úvodní učební text biologie pro 1. ročník gymnázií. 3. upr. vyd. Praha: Fortuna, c2000, 103 s. ISBN 80-716-8714-6. • ZÁVODSKÁ, Radka. Biologie buněk: základy cytologie, bakteriologie, virologie. 1. vyd. Praha: Scientia, 2006, 160 s. ISBN 80-869-6015-3 SOURCES

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