Mitosis and Meiosis Exam 4 pt 2

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  1. Meiosis
    • Sexual reproduction requires a fertilization event in which two haploid gametes unite to create a diploid cell called a zygote
    • Meiosis is the process by which haploid cells are produced from a cell that was originally diploid
  2. Bivalent or tetrad
    • Homologous - pairs of sister chromatids associate with each other, lying side by side to
    • form a bivalent or tetrad
    • Process called synapsis
    • Synaptonemal - complex not required for pairing of homologous chromosomes
  3. Crossing over
    • Physicalexchange between chromosome pieces of the crossing bivalent
    • increase the genetic variation of a species
  4. Chiasma
    arms of the chromosomes tend to separate but remain adhered at a crossoversite
  5. Prophase I
    replicated chromosomes condense and bivalents form as the nuclear membrane breaks down

    • Prometaphase I - spindle apparatus complete, and the chromatids are attached to kinetochore
    • microtubules
  6. Metaphase I
    • bivalents organized along metaphase plate as double row
    • Mechanism to promote genetic diversity
  7. Anaphase I
    • segregation of homologues occurs
    • Connections between bivalents break

    the homologous pair of chromatids moves to the opposite pole
  8. Telophase I
    • sisterchromatids have reached their respective poles and decondense and nuclear
    • membranes reform
  9. Cytokinesis I
    • Original diploid cell had its chromosomes in homologous pairs, while the two cells
    • produced at the end of meiosis I are haploid - they do not have pairs of
    • homologous chromosomes
  10. Meiosis II
  11. Meiosis vs. Mitosis
    • Mitosis - 2 IDENTICAL daughter cells 
    • -6 chromosomes in 3 homologous pairs

    • Meiosis - 4 DIFFERENT daughter cells 
    • - Each daughter has a random mix of 3 chromosome
  12. Chromosome identified by
    • Size
    • Location of centromere
    • Short arm is p, long arm is q, short arms on top
    • Metacentric – middle
    • Submetacentric – off center
    • Acrocentric – near end
    • Telocentric – at the end
    • Banding pattern
  13. Chromosomal Mutation
    Deletions (missing parts)

    Duplication (Section occurs 2 or more times in a row)

    Inversions (Change in direction along a single chromosome

    Translocations (One segment becomes attached to another chromosome)
  14. Euploid
    chromosome number that is viewed as the normal number
  15. Polyploid
    3 or more sets of chromosomes (ie diploid)
  16. Aneuploidy
    • Alteration number of particular chromosomes
    • Total number not an exact multiple of a set
    • usually detrimental
  17. Trisomic
    • Normal 2 copies of a chromosome plus a 3rd
    • 2n+1
  18. Monosomic
    • Missing one of normal copies of a
    • chromosome
    • 2n-1
  19. Monosomic
    • Missing one of normal copies of a
    • chromosome
    • 2n-1
  20. Nondisjunction
    Chromosomes do not sort properly during cell division

    During meiosis can produce gametes with too many or too few chromosomes
Card Set:
Mitosis and Meiosis Exam 4 pt 2
2013-12-15 00:46:54
biology exam
biology exam 4
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