Bio Chap 7
Terms
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- Ordinary cell division produces two daughter cells that are genetically identical. Give three functions of cell division.
- Cell replacement, growth of an organism, asexual reproduction of an organism
- When in the cell cycly does each chromosome consist of two chromatids?
- During G2, the last part of interphase, and during prophase and metaphase of the next mitosis
- An organism called a plasmodial slime mold is one huge cytoplasmic mass with many nuclei. Explain how this "monster cell" could arise.
- Mitosis occurs repeatedly without cytokinesis
- In what sense are the two daughter cells produced by mitosis identical?
- They have identical genes (DNA)
- When a cancer patient is treated with vinblastine, which prevents the mitotic spindle from forming, in what stage of mitosis are dividing cells trapped?
- Prophase
- diploid cell
- contains two homologous sets of chromosomes
- gametes
- a sex cell; a haploid egg or sperm. The union of two gametes of opposite sex (fertilization) produces a zygote
- haploid
- a cell with o single chromosome set
- zygote
- fertilized egg (diploid)
- _____ is to somatic cells as haploid is to _____
- Diploid; gametes
- If a diploid cell with 18 chromosomes undergoes meiosis, the resulting gametes will each have ______ chromosomes.
- 9
- Explain how mitosis conserves chromosome number while meiosis reduces the number in half
- In mitosis, a single replication of the chromosomes is followed by one division of the cell. In meiosis, a single replication of the chromosomes is followed by two cell divisions.
- In what important way is anaphase of meisois II like anaphase of mitosis?
- Sister chromatids separate
- Name two events during meiosis that contribute to genetic variety among gametes.
- Crossing over between homologous chromosomes during prophase I and independant orientation of tetrads at metaphase I
- How does the karyotype of a human female differ from that of a male?
- A female has two X chromosomes; a male has an X and a Y
- What is the chromosomal basis of Down syndrom?
- Three copies of chromosome 21 (trisomy 21)
- Explain how nondisjunction in meiosis could result in a diploid gamete
- A diploid gamete would result if there were nondisjuntion of ALL the chromosomes during meiosis I or II
- How is reciprocal translocation different from normal crossing over?
- Normal crossing over is an exchange of segments between homologous chromosomes; reciprocal translocation occurs between nonhomologous chromosomes.
- Name meiosis/mitosis steps in order
- Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis
- Describe Interphase of mitosis and meiosis
- chromosomes are duplicated but cannot be seen individually
- Describe prophase I of meiosis
- Chromatin condenses. Chromosomes "cross over" and are rearranged. Spindle forms
- Describe Metaphase I of meiosis
- tetrads aligned in the middle of the cell. spindle attaches to the centromeres
- Describe Anaphase I of meiosis
- Chromosomes migrate in pairs to the poles of the cell
- Describe Telophase/Cytokenisis I of meiosis
- Chromosomes arrive at poles. cell splits.
- Describe Prophase(II) of mitosis/meiosis
- spindles form. chromosomes are moved to middles of the cells
- Describe Metaphase(II) of mitosis/meiosis
- aligned in the middle, spindle fibers are attached
- Descibe Anaphase(II) of mitosis/meiosis
- centomeres are separated and sister chromosomes move to the opposite poles of the cells
- Describe Telophase(II)/Cytokenesis of mitosis/meiosis
- nuclei form, and cytokinesis (splitting of the cell) occurs at the same time
- tetrad
- 2 sets of homologous chromosomes (sister chromosomes) stuck together in Prophase I of meiosis