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The cell cycle

  1. Why do cells divide ?
    • - For reproduction = asexual reproduction.
    • - For growth = from zygote to multicelled organism. 
    • For repair and growth
  2. Haploid
    1 set of chromosomes
  3. Diploid ( 2n)
    - 2 sets of chromosomes
  4. Centromere
    This is the point on which the chromatids are attached
  5. Chromatin
    This is unpacked or unwrapped DNA
  6. Chromatids
    - the replicated strands of DNA ( so like chromosome kind of shape)
  7. Chromosomes
    - These are condensed DNA
  8. Genome
    This is a cells genetic information
  9. Gametes
    - these are reproductive cells ( eggs and sperms )
  10. Somatic cells
    These are body cells
  11. Maternal vs Partenal
    • Maternal - chromosome from Mom 
    • Partenal - chromosome from Dad
  12. Interphase facts ( mitosis )
    • - 90% of the cell cycle
    • - prepares for cell division by building new proteins ( enzymes, membranes ) 
    • - single stranded chromosomes duplicate.
    • - They are three phases ( G1 = growth period for newly formed cell l.  S phase = synthesis of DNA ( sister chromatids) 
    • G2= rebuilding energy reserves ( preparation for mitosis, produces proteins
  13. Mitosis stages
    • Prohapse
    • metaphase 
    • Anaphase 
    • telophase 
    • ( the other 10%)
  14. Prophase ( 1st stage )
    • - The chromatin condenses and the chromosomes are visible.
    • - Then the centrioles begin to move to opposite ends of the cell in ONLY animal cells.
    • - Then the micro tubules cross cell to form mitotic spindle asters  and attaché to the kinetochore on the centromere. 
    • - Nucleous disappears and the nuclear membrane breaks down
  15. Metaphase
    • - 2nd stage 
    • - chromosomes in the metaphase stage move to the metaphase plate \ Equatorial  plate 
    • - Centrioles at opposite poles
  16. Anaphase
    • - 3rd stage 
    • - the paired centromeres separate and the sister chromtids are liberated . 
    • - Chromatids move to opposite poles ( centrioles) 
    • -
  17. Kinetochores
    • - This is the use of motor proteins that walk chromosomes along attached microtubule. 
    • - they eat the microtubule as they make their way to the centrioles
  18. Telophase
    • - Chromatids reach the poles and start to unpack  to become chromatin 
    • - Daughter Nuclei form ( surrounded by forming envelopes)
    • - cytokinesis ends when a cleavage furrow begins to show. 
    • - Cytokeneis ( is the cell plate for plants )
    •  - forming 2 identical daughter cells. 
    • -
  19. Cell cycle regulation
    • - Check points = G1, G2, M 
    • - cell cycle is controlled by stop and go chemical signals at critical points. 
    • - The signals indicate if key cellular processes have been completed correctly.  
    • - the Cyclin protein = Go 
    • - G2 phase cyclin protein is turned on by CDK ENZYMES ( kinase enzymes) with the help of phoshorolation  to produce  mitosis promoting factor ( MPF).
    •  - as mitosis proceeds they degrade
  20. Growth factors ( types of cells cycle regulations
    - the hormonal signals are either on or off
  21. Density independent inhibition
    • - the crowded cells stop dividing 
    • -
  22. Apoptosis
    - genetically programmed death
  23. Cancer
    • - uncontrollable cell duplication of non functioning cells. 
    •  - can form tumours 
    • - spread ( metastasis)
Author
wish_uwereme
ID
362842
Card Set
The cell cycle
Description
Updated

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