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The Continuity of Life

The Continuity of Life. Mrs Tagore. Key words: Histone proteins Centromere Karyotype Homologous Autosome Heterosome Sex chromosomes Haploid Diploid Somatic cell Locus/loci Alleles Homologous chromosomes Plasmid nucleoid. Chromosomes and Eukaryotes. Read pages 15-16.

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The Continuity of Life

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  1. The Continuity of Life Mrs Tagore

  2. Key words: • Histone proteins • Centromere • Karyotype • Homologous • Autosome • Heterosome • Sex chromosomes • Haploid • Diploid • Somatic cell • Locus/loci • Alleles • Homologous chromosomes • Plasmid • nucleoid

  3. Chromosomes and Eukaryotes Read pages 15-16

  4. Chromosomes and Eukaryotes Read pages 15-16

  5. Chromosomes and Eukaryotes Read pages 17-18

  6. Chromosomes of Prokaryotes Read pages 18-19

  7. Questions • Complete questions 1-10 for tomorrow. • We will be discussing these in class, so I’ll be checking that you have done it!!

  8. Title: Mitosis Learning question: What are the names of the stages of mitosis? Hook: What connects these pictures? (Can you write more than one word?!)

  9. Lesson Aims • Describe the cell cycle • Understand that mitosis is only one small part of the overall cell cycle • State the events that occur at each phase of the cell cycle • Describe each stage of mitosis • Identify each stage of mitosis from diagrams and micrographs

  10. Key words… • Mitosis • Prophase • Metaphase • Anaphase • Telophase • Microtubules • Cytokinesis • Chromatid • Chromasome • Centromere • Centriole • Diploid

  11. Cell division • All complex organisms originated from a single fertilised egg. • Every cell in your body started here, through cell division the numbers are increased. • Cells then specialise and change into their various roles

  12. Mitosis • Mitosis is the process by which new body cell are produced for: • Growth • Replacing damaged or old cells. This is a complex process requiring is to be split into different stages to understand it.

  13. DNA • ‘Blueprint of life’ • Codes for all the proteins needed for life • Describes that characteristics of every living thing • Every cell with a nucleus contains ALL the instructions to make the organism • http://www.pbs.org/wgbh/nova/photo51/media/journey.swf

  14. Chromosomes • Each DNA strand is split into chromosomes • All sexually reproducing animals have pairs of chromosomes. One set of each pair comes from each parent • Humans have 23 pairs • Lions have 19 pairs • African wild dogs have 39 pairs • Mosquito have 3 pairs • Some ferns have 500-600 pairs

  15. This (imaginary, example) animal has just two pairs of chromosomesRed = Maternal Blue = Paternal 1p 1m 2p 2m

  16. During Interphase, each chromosome replicates and produces an exact copy of itself: 1p + copy 1m + copy 2p + copy 2m +copy

  17. There are four stages to Mitosis • Prophase • Metaphase • Anaphase • Telophase • Remember though that this is a continuous process P M A T

  18. Interphase • Standard condition of cell • DNA replicates • Cell enters reproductive cycle with 2 copies of each chromosome

  19. Prophase • DNA super coils and chromosomes become visible • Nuclear membrane breaks down • Centrioles migrate to poles

  20. Metaphase • Chromosomes line up centromeres on equator of cell • Centrioles form spindles

  21. Anaphase • Spindles ‘grip’ centromeres and chromosomes migrate to poles

  22. Telophase • Nuclear membranes reform • Chromosomes disperse • Cytokinesis begins

  23. Interphase • Both daughter cells are exact copies of the parent cell

  24. INTERPHASE MITOSIS

  25. Stages of Mitosis • http://www.cellsalive.com/mitosis.htm

  26. In humans, each cell (except sex cells) has how many chromosomes? ______ • After mitosis, how many daughter cells are produced?  _______.  After mitosis (in a human cell), each daughter cell has how many chromosomes? _____ • How many phases are in MITOSIS? ___________ • Which phase of the cell cycle is the longest?  _________ • During which phase does cytokinesis begin?  __________ • What cell parts migrate to the poles during prophase? __________________. • What structure holds the two chromatids together? ____________________ • During which phase does the nuclear membrane dissolve? __________________ • What structure moves the chromosomes into position and then pulls them apart? ___________________ • What is the overall purpose of mitosis? _________________________

  27. Name the stages!

  28. Binary fission

  29. Binary fission • Prokaryotes reproduce by binary fission • No nucleus, centromere or chromosomes, therefore no mitosis • Two daughter cells produced • Cell replication>new DNA attaches itself to different part of cell membrane>cell pulls apart separating replicate and original DNA> wall forms dividing cells into two cells with identical genetic composition • Mitochondria and chloroplasts also use binary fission to form new organelles

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