Bio Lab quiz 4 part 1

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tjtolman
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139227
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Bio Lab quiz 4 part 1
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2012-03-14 17:05:59
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bio lab quiz 4 part 1
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  1. Asexual reproduction:
    • Duplication of self (does not require 2 gametes)
    • Replicating DNA
    • Mitosis is this type of cell division

    • Advantages: Takes less energy
    • Disadvantage: No variabity=No adaptation (bad for natural selection)
  2. Sexual Reproduction:
    • Gametes (haploid,n) come together during fertilization to produce offspring
    • MEIOSIS

    • Advantages: increased variation
    • Disadvantages: requires more energy
  3. Chromatin:
    40% DNA and 60% protein
  4. Euchromatin:
    Only condensed during cell division. At other times it is uncoiled (found at the expressed portions of DNA)
  5. Heterochromatin:
    Always condensed (portion of the DNA in not expressed)
  6. Chromatid:
    One of two identical strands of a chromosome

    Sister chromatids: two identical copies of a chromatid connected by a centromere.

    When two strands seperate they are called DAUGHTER CHROMOSOMES.
  7. Chromosome:
    A single piece coiled DNA, mad of chromatin

    Homologous chromosomes: Two different copies of the same chromosome (can be single or double stranded)

  8. More chromatids and chromosomes:
  9. Mitosis vs meosis:
    • Mitosis: results in the seperatin of replicated chromosomes into two identical daughter nuclei
    • -somatic cell: body cells, two sets of chromosomes (diploid,2n)

    • Meiosis: results in daughter cells with 1/2 chromosomes of the parent cell
    • -gamete: sex cells, one set of chromosomes (haploid,1n)
  10. Interphase:
    the period between mitotic and meiotic division in which there is cell growth and DNA replication.
  11. Cytokinesis:
    Division of one cell into two cells
  12. MITOSIS PICTURE:
  13. Mitossis *interphase:
    • (longest phase)
    • G1: gap1 synthesis of mRNA for use in protein synthesis (takes 6-12)
    • S: synthesis, DNA is synthezied (replicated), going from one chromatid to sister chromatid (6hours)
    • G2: gap 2, synthesis of molecules and structures needed for mitosis (5hours)
  14. Mitosis: interphase checkpoints:
    • Control mechanisms that ensure cell division is proceeding acurately.
    • G1/S: check for enough proteins, general health of cell, and DNA damage.
    • G2/M: looks at DNA damage that occured during replication.
    • -Apoptosis (cell suicide)
    • -Go back to interphase and correct process
  15. Mitosis: Prophase
    • Condensing of the chromosomes (easier to move)
    • Nuclear membrane begins to breakdown
    • Nucleoli disappear
    • Beging to form spindles (Actin fibers)
    • Maturation of kinetochores (proteinaceous material on the sides of the centromere)
  16. Mitosis: metaphase
    • Kinetochores attach the chromosomes to the spindles
    • chromosomes align along the mitotic plate
    • There is also a spindle checkpoint
  17. Mitosis: Anaphase
    • Seperatin of chromosomes
    • Sister chromatids begin to move towards the poles via spindles (forming identical cells)
  18. Mitosis: Telophase
    • Cytokinesis occurs (cell plate formation in plants and cleavage furrow in animals
    • Spindles dissasemble
    • Kinetochores disappear
    • Nuclear membrane reforms
    • Nucleoli reappear
    • Chromosomes become uncondensed
  19. Mitosis in short:
    • Interphase: prepare
    • Prophase: condense
    • Metaphase: line up
    • Anaphase: split
    • Telophase/Cytokinesis: two new dipliods
  20. Onion/Garlic root tip slides:
  21. Meiosis I picture:
  22. Meiosis II:
  23. Meiosis I:
    • •Pre-meiotic Interphase:
    • –prepare cell for division
    • –replication of chromosomes

    • •Prophase I:
    • chromosomes condense
    • –Formation of spindles and centrioles
    • –Homologous chromosomes pair in synapse forming tetrads

    –Crossing over and recombination (chiasmata)
  24. Meiosis I continued:
    • •Metaphase I:
    • –Tetrads line up
    • –Chromosome position is random (independent assortment of chromosomes)

    • •Anaphase I:
    • –Homologous chromosomes separate

    • •Telophase I:
    • –One chromosome of each pair arrives at pole
    • –Cytokinesis occurs
  25. Meiosis II:
    • •Interkinesis (Interphase II):
    • –Cell prepares for division
    • –NO DNA replication

    • •ProphaseII:
    • –Chromosomes reappear
    • –Spindles form
    • –Nuclear membrane breaks down
  26. Meiosis II continued:
    • •MetaphaseII:
    • –Chromosomes line up

    • •AnaphaseII:
    • –Sister Chromatids separate

    • •TelophaseII:
    • –Chromatids arrive at poles
    • –Cytokenesis occurs
  27. Spermatogenesis:
    • Males:
    • •Maintain many cells (spermatogonia) that
    • are diploid and can constantly undergo mitosis

    • •Two daughter cells (primary
    • spermatocytes) go through meiosis to produce four haploid cells (spermatids)

    •Spermatids mature into sperm

    •Process takes 9 weeks
  28. Oogenesis:
    • •During fetal development, oogonia undergo
    • mitosis to produce primary oocytes that will arrest in prophase I

    •These oocytes are the only ones a female will have throughout her life

    •Upon ovulation, an oocyte completes prophase I

    •Only one secondary oocyte is produced (other half becomes a polar body)

    •The process stops in metaphase II

    • •Meiosis II continues after fertilization and a 2nd
    • polar body is formed

    • •The male pronucleus and the oocyte
    • nucleus fuse forming the zygote.
  29. Gametogenesis
  30. Abnormalitites:
    •Due to alterations in the # of chromosomes

    •Nondisjunctionà the improper separation of chromosomes or chromatids during mitosis or meiosis

    •Causes abnormal pairing and crossover, pre-mature separation of the tetrad, or pre-mature separation of sister chromatids

    •Results in too many or too few chromosomes
  31. Trisomy 21 (Down Syndrome)
    • •Short stature
    • •Sometimes reduced mental capacity
    • •Short fingers
    • •Little fingers curved inward
    • •Cardiac abnormalities
    • •Pre-mature aging
    • •Immunodeficiency problems
  32. Kleinfelter syndrome (47, XXY)
    • •Have small testes
    • •Sometime have breast development
    • •Often tall in stature
    • •Usually sterile
  33. Turner syndrome (45, X0)
    • •Short in stature
    • •Have a web neck
    • •Poor breast development
    • •Failure to menstruate
    • •Sterility
    • •Normal intelligence with spatial intelligence problems

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