Cell cycle 3.2.2

• What are the stages of the cell cycle?

  InterphaseProphase MetaphaseAnaphaseTelophaseCytokinesis
• What is mitosis?

  Nuclear division within a eukaryotic cell that produces two daughter nuclei that are genetically identical to the parent nuclei as well as each other
• What is the importance of cell division?

  GrowthRepairReproduction
• Describe interphase

  -cellular contents duplicate-two centromeres form-chromosomes duplicate-the cell "double checks" the duplicated chromosomes for errors, making any repairsG1=duplicationS=DNA replicationG2=checking for errors

  
• Describe prophase


  -chromosomes condense and become visible (appear as chromatids), joined by centromere-centrioles move to opposite poles of the cell-spindle fibres form-nuclear envelope disintegrates and nucleolus disappears

  
• Describe metaphase


  -chromosomes attach to spindle fibres by their centromeres-line up at right angles along the equator

  
• Describe anaphase

  -centromeres divide into two-spindle fibres shorten and pull chromatids to opposite poles of the cell (centromere first)

  
• Describe telophase

  -chromatids have reached the poles and are referred to as chromosomes again-chromosomes decondense and lose visibility -spindle disintegrates -nuclear envelope reforms and nucleolus reappears-nuclear division is complete

  
• Describe cytokinesis

  Cell membrane divides to form two genetically identical cell

  
• Explain why the cell cycle does not occur in some cells

  After differentiation, some types of cell in multicellular organisms no longer have the ability to divide.So stem cells are used
• process of binary fission in bacteria

  1)cell replicates DNA2)plasmids replicate2)cytoplasmic membrane elongates, separating DNA molecules 3)cross wall forms, membrane invaginates4)cross wall forms completely 5)produces two daughter cells

  
• Use of logs


  Makes it easier to plot very small and very large numbers on a graph
• How to use logs

  Use calculator, log 10 then input number
• Differences in cell cycle between plant and animal cells

  
• Mass of DNA during cell cycle

  
• Differences in cell cycle between plant and animal cells

  
• What is cancer?

  Cancer is caused by changes (mutations) to the DNA within cells. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well as how to grow and divide.
• Mass of cell content and DNA during cell cycle

  
• What two genes control mitosis?

  Oncogenes= like an on gene (proto-oncogene= always on, can cause cancer)Tumour suppressor gene= like a off gene (activated=good thing, stops tumour developing, inactivated= can lead to cancer)
• Factors which increase the risk of mutations which can cause cancer

  -smoking -too much sugar/fat-overweight-lack of exercise
• Treating cancer

  —>involves killing rapidly dividing cells-preventing DNA replication -inhibiting metaphase by interfering with spindle fibre formation
• Problem with cancer treatment

  Inferred with other rapidly dividing cells (eg. Hair follicle cells)
• The events that take place during interphase and mitosis lead to the production of two genetically identical cells. Explain how.

  1. DNA replicated2. Involving complementary base pairing3. Produces two sister chromatids4. Each chromatid moves to opposite poles of the cell to be separated