IB Biology Core 2.5: Cell Division
•Download as PPTX, PDF•
6 likes•7,911 views
The document outlines the key stages of the cell cycle, including interphase (G1, S, G2 phases), mitosis, and cytokinesis. It describes that interphase involves DNA replication and protein synthesis. The four stages of mitosis are then described: prophase, metaphase, anaphase, and telophase. It is explained that mitosis produces two genetically identical daughter cells through the duplication and separation of chromosomes. Cell division through mitosis is described as essential for growth, development, tissue repair, and asexual reproduction.
Report
Share
IB Biology Core 2.5: Cell Division
- 1. IB Biology 2 Cells 2.5 Cell Division All syllabus statements ©IBO 2007 All images CC or public domain or link to original material. Jason de Nys http://commons.wikimedia.org/wiki/File:Scotchquaileggs.jpg
- 2. 2.5.1 Outline the stages of the cell cycle, including interphase (G1, S, G2), mitosis and cytokinesis Interphase is the longest portion of a cell’s life and has three subdivisions: First Gap G1 http://commons.wikimedia.org/wiki/File:First_gap_cell_lifecycle.svg
- 3. Synthesis S http://commons.wikimedia.org/wiki/File:Synthesis_cell_lifecycle.svg
- 4. Second Gap G2 http://commons.wikimedia.org/wiki/File:Second_gap_cell_lifecycle.svg
- 5. Mitosis: 4 Main stages http://commons.wikimedia.org/wiki/File:Prophase_procariotic_mitosis.svg ttp://commons.wikimedia.org/wiki/File:Metaphase_procariotic_mitosis.svg media.org/wiki/File:Anaphase_procariotic_mitosis.svghttp://commons.wiki The cell divides it’s chromosomes into 2 identical sets media.org/wiki/File:Telophase_procariotic_mitosis.svg Detail in 2.5.4
- 7. Stage Events Gap 1 (G1) • Protein Synthesis • Organelles produced • Cytoplasm increases in size Synthesis (S) DNA is duplicated Gap 2 (G2) • Organelles produced • Cytoplasm increases in size Mitosis The cell divides it’s chromosomes into two identical sets 4 Stages • Prophase • Metaphase • Anaphase • Telophase Cytokinesis The parent cell divides into two daughter cells
- 8. 2.5.2 State that tumours (cancers) are the result of uncontrolled cell division and that these can occur in any organ or tissue. In cancerous cells, control of mitosis has been lost and they divide… and divide… and divide. This leads to tumours (cancer tissue) that displaces healthy tissue and interferes with proper function. Cancer can arise from any cells capable of mitosis Background: A Brenner tumour in an ovary. These are usually benign, but can be malignant http://commons.wikimedia.org/wiki/File:Brenner_tumour_intermed_mag.jpg
- 9. 2.5.3 State that interphase is an active period in the life of the cell when many metabolic reactions occur, including protein synthesis, DNA replication, and an increase in the number of mitochondria and chloroplasts. State: give a specific name, value or other brief answer without explanation or calculation The name ‘interphase’ implies a period of time between stages and that nothing much is going on. This is not the case! This is when the cell is going about it’s day-to-day ‘business’ i.e. carrying out it’s programmed functions and growing. Imagine if cells did not have a growth phase. What would happen to the size of daughter cells with progressive rounds of mitosis?
- 10. Think: What else would have to stop when the chromatin is tightly coiled and condensed into chromosomes for mitosis? http://commons.wikimedia.org/wiki/File:Chromosome.svg
- 11. That’s right, transcription can’t be done when the DNA is tightly coiled. So Interphase is when all of the cell’s genetic instructions are processed. http://commons.wikimedia.org/wiki/File:Chromosome.svg
- 12. Extension: http://www.flickr.com/photos/seyyed_mostafa_zamani/4266283238/
- 13. 2.5.4 Describe the events that occur in the four stages of mitosis ^C
- 17. Prophase Metaphase Anaphase First 3D video of mitosis. Source forgotten, let me know if you know! Telophase
- 18. Pea MAT http://www.flickr.com/photos/cmatsuoka/3732303102/ http://www.flickr.com/photos/zaser/2524931166/
- 19. People Meet And Talk http://www.flickr.com/photos/chuckp/252924532/
- 20. 2.5.5 Explain how mitosis produces two genetically identical nuclei Think back to slide 3… What happens during the synthesis part of interphase?
- 21. Synthesis S http://commons.wikimedia.org/wiki/File:Synthesis_cell_lifecycle.svg
- 22. So, the chromosomes in the nucleus have been exactly copied See: Replication Core 3.4, AHL 7.2 During Prophase the Chromatin condenses into the familiar X shaped chromosome, which is actually two identical chromatids joined at the centromere. And then when the chromosomes split in half during anaphase, the identical chromatids are dragged to opposite ends of the cell Cytokinesis cuts the cell in half, with one set of duplicate DNA in one daughter cell and the other identical set in the other daughter cell ∴ Both nuclei are ∴ Both nuclei are identical identical http://www.flickr.com/photos/wellcomeimages/5987498303/http://w ww.flickr.com/photos/thejcb/4117622551/
- 23. 2.5.6 State that growth, embryonic development, tissue repair and asexual reproduction involve mitosis Any time new cells are required, mitosis is required: • Growth: An 18 year old has many more cells than an 18 month old! • Embryonic development: You start as a zygote, one cell! • Tissue repair: Burnt, bashed, cut or eaten; dead or lost cells need to be replaced. • Asexual reproduction: In eukaryotes only remember: what do prokaryotes do?
- 24. Make your own Play Doh™ or Plasticine™ mitosis model to further your understanding make your own playdough! http://www.flickr.com/search/?l=cc&mt=all&adv=1&w=all&q=mitosis&m=text
- 25. Further information: Three of the best sites for IB-specific Biology information. The top link takes you to the PPT by Stephen Taylor