Bio Exam 2- Mitosis

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Bio Exam 2- Mitosis
2013-10-21 15:57:07

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  1. mitosis is an...
    asexual division
  2. mitosis is part of the cell cycle, which is what?
    the life cycle of the cell
  3. mitosis makes new cells that are...
    exactly the same as the original cells
  4. for cells that divide by mitosis, there are 3 steps in the cell cycle:
    • interphase
    • mitosis
    • cytokinesis
  5. interphase
    • most of a cell's life is spent in interphase
    • normal functions are carried out
    • three stages of interphase: G1, S, G2
  6. G1 (Interphase)
    • first gap or growth phase
    • organelles duplicated
    • cells get larger
  7. S (Interphase)
    • synthesis phase
    • DNA is copied in this phase
    • chromosomes are replicated
    • get sister chromatids connected by centromeres
  8. G2 (Interphase)
    • second gap phase
    • synthesis of proteins necessary for mitosis
  9. the purpose of mitosis is to separate the sister chromatids so that...
    each new cell has a complete set of chromosomes
  10. before dividing, a copy of ___ must first be made
  11. DNA is located in the nucleus and carries genes, which are...
    instructions for building the proteins that cells require
  12. DNA is organized into structures called chromosomes which...
    can carry hundreds of genes along their length
  13. the number of genes in each cell depends on...
    the organism; humans have 46
  14. DNA starts out in...
    a string-like, uncondensed form
  15. before cell division, DNA is condensed into...
    short, linear chromosomes
  16. when a chromosome is replicated during cell division...
    the copy carries the same genes
  17. each chromosome is copied and the copy is called a ____
    sister chromatid
  18. the sister chromatid is connected to the original DNA by a ____
  19. DNA is a double stranded molecule made of...
    two single strands of nucleotides that are bonded together
  20. the DNA molecule looks a lot like...
    a twisted rope ladder
  21. the "handrails" of the molecule are called the backbone which is made of...
    sugars and phosphates
  22. the ____ and ____ parts of the nucleotides are connected
    sugar and phosphate
  23. the "rungs" of the molecule are the bases:
    • A (adenine)
    • T (thymine)
    • G (guanine)
    • C (cytosine)
  24. the bases across the "ladder" are connected in a specific way
    • A always bonds with T
    • C always bonds with G
  25. the connection between the molecules in the ladder are...
    hydrogen bonds
  26. James Watson and Frances Crick
    • determined the structure of the DNA molecule
    • published in Nature in 1953
  27. DNA molecule separates at _____ that hold bases together
    hydrogen bonds
  28. the enzyme ______ adds the correct base to the now single strand of DNA
    DNA polymerase
  29. the _____ between sugars and phosphates is made
    covalent bond
  30. DNA replication results in...
    two identical DNA molecules
  31. each new DNA molecule is...
    half new and half from the old molecule
  32. when an entire chromosome is copied, the two sister chromatids are connected...
    at the centromere
  33. after DNA replication, the cell is ready...
    to divide
  34. steps of mitosis
    • prophase
    • metaphase
    • anaphase
    • telophase
  35. prophase
    • replicated chromosomes condense
    • microtubules form at the poles (ends) of the cell
    • the nuclear envelope disintegrates
  36. metaphase
    • replicated chromosomes line up across the equator of the cell
    • microtubules attach to the centromeres
  37. anaphase
    • the centromere splits
    • microtubules pull sister chromatids apart towards poles
  38. telophase
    • nuclear envelopes reform around chromosomes
    • chromosomes revert to uncondensed form
  39. what is cytokinesis?
    the cell itself divides in half creating two identical daughter cells
  40. for plant cells, rigid cell wall prevents...
    cell membrane from pinching in
  41. prophase, metaphase, anapase, and telophase are similar in plant cells to _______
    animal cells
  42. during cytokinesis, a ____ from vesicles made of _________ and proteins that will become a new cell wall
    cell plate; cellulose
  43. animal cells produce a band of filaments that...
    divide the cell in half
  44. after cytokinesis, cell reenters the G1 phase interphase and...
    repeat the cell cycle if the conditions are right
  45. cells that go through the cell cycle in unfavorable conditions can lead to...
  46. checkpoints
    cell determines if cell is ready to enter next part of cell cycle
  47. when the proteins that regulate the cell cycle don't work...
    • the cell divides uncontrollably
    • results in a tumor
  48. mutations in the DNA can produce...
    nonfunctioning proteins
  49. mutations can be inherited or induced by exposure to...
    carcinogens that damage DNA and chromosomes
  50. mutations can be in cell control proteins called...
    • proto-oncogenes¬†
    • proto: before
    • onco: cancer
  51. proto-oncogenes
    • normal genes on many different chromosomes
    • regulate cell division
    • when mutated, they become oncogenes¬†
    • many organisms have proto-oncogenes
    • many organisms can develop cancer
  52. proto oncogenes carry instructions for what building growth factors?
    • stimulate
    • cell division when needed
  53. oncogenes overstimulate...
    cell division
  54. receptor proteins on the surface of a cell...
    recognize and bind to a specific chemical signal
  55. tumor suppressors are genes that...
    carry instructions for producing proteins that stop cell division if necessary
  56. suppressors are backup in case...
    protooncogenes are mutated
  57. suppressors can be...
  58. in suppressors, cells can override the...
  59. angiogenesis
    • growth of blood cells caused by secretions from cancer cells
    • cancer cells can divide more
    • tumors develop, sometimes filling entire organs
  60. contact inhibition in normal cells
    prevents them from dividing all the time, which would force the new cells to pile up on each other
  61. anchorage dependence in normal cells...
    keeps the cells in place
  62. cancer cells divide too quickly and can...
    leave the original site and enter the blood, lymph, or tissues
  63. most cells divide a set number (60-70) of times, then they stop dividing, which...
    limits benign tumors to small sizes
  64. cancer cells can divide indefinitely, as they are ____ through the manipulation of the enzyme _____
    immortal; telomerase
  65. many changes, or hits, to the cancer cell are required for...
  66. multiple hit model describes...
    the process of cancer development
  67. mutations can be inherited and/or can stem from...
    • environmental exposures
    • knowledge of cancer risk factors is important