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Flashcards

9: the cell cycle

Jaimee Mc biology 1115 Inglês 46 flashcards

Flashcards do conjunto (46)

  1. 1spontaneous generation- the belief that insects and other small animals cane from rotting vegetation
    - was eventually incorporated into Christian philosophy
    - was proved wrong
  2. 2cell division- part of the cell cycle
    - how cell reproduction happens
    - must produce identical copies of genetic material (DNA)
  3. 3cell cycle- refers to the life of a cell (from origin from parent cell to division into two)
    - vital for development from fertilized egg, repair of tissues, and cell replacement
  4. 4genome- the DNA thats duplicated (the cells genetic information)
  5. 5prokaryotic genome- a single, circular DNA molecule.
  6. 6eukaryotic genome- several linear DNA molecules, known as chromosomes
  7. 7human somatic cells- have 46 chromosomes
  8. 8human gametes- have 23 chromosomes
  9. 9histones- proteins that maintain DNA structure and help control gene activity
  10. 10chromatin- the DNA and the histones (DNA-protein complex)
    - organized into long thin fibers
  11. 11chromosome- a single DNA molecule, with genes for a specific set of traits on it
    OR
    - two identical DNA molecules joined at a centromere (has two identical sister chromatids)
  12. 12chromatid- one of a pair of joined DNA molecules in a chromosome
  13. 13mitosis- the first step in cell duplication
    - two daughter nuclei are formed
    - usually followed by cytokinesis - producing 2 daughter cells
    - produces two cells that are the genetic equivalent of the parent cell
  14. 14cytokinesis- division of the cytoplasm
    - follows mitosis
    - produces two daughter cells
    - produces two cells that are the genetic equivalent of the parent cell
  15. 15somatic cells- 'body' cells
    - most cells in multicellular organisms
    - have diploid (2n) number of chromosomes
  16. 16gametes- eg. sperm and egg cells
    - where somatic cells got their chromosomes
    - have haploid (n) number of chromosomes
    - produced only in gonads
  17. 17zygote- a fertilized egg
    - undergoes millions of cycles of mitosis and cytokinesis to produce a fully-developed, multicellular organism.
  18. 18meiosis- yields 4 daughter cells - each with half the chromosome number of the parent (humans = 23)
    - reduces the number of chromosomes in a cell
  19. 19mitotic phase- usually includes both mitosis and cytokinesis
  20. 20interphase- 90% of cells life
    - cell grows by producing proteins and cytoplasmic organelles, it copies its chromosomes and prepares for cell division
    - 3 sub-phases
    - by late interphase the chromosomes have been duplicated / the centrosome has been duplicated (begins to organize microtubules into an aster)
  21. 21interphase: G1 phase- centered on growth, lasts 4-5 hours
  22. 22interphase: S phase- synthesis (duplication) of DNA
    6-8 hours
  23. 23interphase: G2- cell completes its preparations for cell division
    - 7-9 hours
  24. 244 phases of mitosis- prophase
    - metaphase
    - anaphase
    - telophase
  25. 25centrosomes- organelles that organize microtubules
    - in animal cells there is a pair of centrioles
  26. 26prophase- the chromosomes are tightly coiled
    - the nucleoli disappear
    - the mitotic spindle begins to form - seem to push the centrosomes away from eachother
  27. 27metaphase- the nuclear envelope begins to break down
    - microtubules from the spindle begin to attach to the chromosomes
    - microtubules from one pole attach to of two kinetochores (regions on the centromere)
    - move chromosomes to the metaphase plate (this defines metaphase)
  28. 28anaphase- centromeres divide - separating sister chromatids
    - each chromatid moves toward the pole to which its spindle fibers are attached
    - by the end of anaphase, each pole will have equal collections of chromosomes
  29. 29telophase- the cell continues to elongate as free spindle fibers from each centrosome push against each other
    - two new nuclei begin to form
    - chromatin becomes less coiled
    - cytokinesis begins
  30. 30mitotic spindle- fibers composed of microtubules and associated proteins
    - major driving force of mitosis
    - elongate by adding subunits of tubulin
    - assembly begins in the centrosome
  31. 31kinetochore- one for each sister chromatid
    - made of proteins and chromosomal DNA
    - located at the centromere
    - spindle microtubules attach here during metaphse
  32. 32sister chromatids moving to opposite poles- chromatids walk along microtubules to the poles
    - spindle fibers shorten during anaphase from the end attached to the chromosome
    - microtubules are possibly taken apart and the kinetochore end
  33. 33contractile ring- made of actin microfilaments
    - gets pulled tighter and tighter and eventually pinches the cell in two
  34. 34cell plate- part of telophase in plants
    - vesicles containing wall materials merge at the metaphase plate and create this
    - enlarges until its membranes fuse with plasma membrane at the perimeter
    - forms cell wall between two daughter cells
  35. 35bacterial reproduction- genes are located in a single bacterial chromosome - circular DNA molecule
  36. 36origin of replication- where chromosome replication begins during binary fission
  37. 37cell cycle control system- a sequence of events with specific molecule triggers
    - cell must pass all checkpoints before going on to the next part of the cycle
  38. 38G1 checkpoint`- most important for most cells
    - if signal is received the cell completes the cell cycle and divides
    - if the cell does not get this then it switches to Go phase and does not divide
  39. 39cyclins- proteins whose concentrations rise and fall within the cell in a rhythmic fashion
    - link to protein kinases, and activate them
    - protein kinases are known as cyclin-dependent kinases (Cdks)
  40. 40maturation-promoting factor- triggers the cell’s passage past the G2 checkpoint, into the M phase
    - promotes mitosis by phosphorylating a variety of other protein kinases
    - stimulates fragmentation of the nuclear envelope
  41. 41M-phase checkpoint- ensures that all the chromosomes are properly attached to the spindle at the metaphase plate before starting anaphase
    - ensures that daughter cells don’t end up with missing, or extra chromosomes
  42. 42growth factors- important for mammalian cells
    - proteins released by a group of cells that stimulate other cells to divide
    - key in density-dependent inhibition of cell division
  43. 43anchorage dependence- To divide they must be anchored to something, usually the extracellular matrix of a tissue
    - Cancer cells are free of both density-dependent inhibition and anchorage dependence
  44. 44cancer- begins when a single cell in a tissue undergoes a transformation that converts it from a normal cell to a cancer cell
    - , cells that evade destruction proliferate to form a tumor, a mass of abnormal cells
  45. 45benign tumor- If the abnormal (cancer) cells remain at the originating site
  46. 46malignant tumor- the cancer cells leave the original site to impair the functions of one or more organs
    - they metastasize

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biology 1115 FlashCards sobre 9: the cell cycle, criado por Jaimee Mc em 05-11-2018.
Criado por
Jaimee Mc
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