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CHAPTER 6
1. Figure 6.4 Which of the following is the correct order of events in mitosis?
Sister chromatids line up at the metaphase plate.
The kinetochore becomes attached to the mitotic spindle.
The nucleus re-forms and the cell divides.
The sister chromatids separate.
The kinetochore becomes attached to the mitotic spindle.
The sister chromatids separate.
Sister chromatids line up at the metaphase plate.
The nucleus re-forms and the cell divides.
The kinetochore becomes attached to metaphase plate.
Sister chromatids line up at the metaphase plate.
The kinetochore breaks down and the sister chromatids separate.
The nucleus re-forms and the cell divides.
The kinetochore becomes attached to the mitotic spindle.
Sister chromatids line up at the metaphase plate.
The kinetochore breaks apart and the sister chromatids separate.
The nucleus re-forms and the cell divides.
- The kinetochore becomes attached to the mitotic spindle.
- Sister chromatids line up at the
- metaphase plate.
- The kinetochore breaks apart and the sister chromatids separate.
- The nucleus reforms and the cell divides.
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CHAPTER 6
2. A diploid cell has ________ the number of chromosomes as a haploid cell.
one-fourth
one-half
twice
four times
twice
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3. An organism’s traits are determined by the specific combination of inherited ________.
cells
genes
proteins
chromatids
genes
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4. Chromosomes are duplicated during what portion of the cell cycle?
G 1 phase
S phase
prophase
prometaphase
S phase
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5. Separation of the sister chromatids is a characteristic of which stage of mitosis?
prometaphase
metaphase
anaphase
telophase
anaphase
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6. The individual chromosomes become visible with a light microscope during which stage of mitosis?
prophase
prometaphase
metaphase
anaphase
prophase
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7. What is necessary for a cell to pass the G 2
checkpoint?
cell has reached a sufficient size
an adequate stockpile of nucleotides
accurate and complete DNA replication
proper attachment of mitotic spindle fibers to kinetochores
accurate and complete DNA replication
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CHAPTER 6
8. ________ are changes to the nucleotides in a segment of DNA that codes for a protein.
Proto-oncogenes
Tumor suppressor genes
Gene mutations
Negative regulators
Gene mutations
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CHAPTER 6
9. A gene that codes for a positive cell cycle regulator is called a(n) ________.
kinase inhibitor
tumor suppressor gene
proto-oncogene
oncogene
proto-oncogene
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10. Which eukaryotic cell-cycle event is missing in binary fission?
cell growth
DNA duplication
mitosis
cytokinesis
mitosis
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11. FtsZ proteins direct the formation of a ________ that will eventually form the new cell walls of the daughter cells.
contractile ring
cell plate
cytoskeleton
septum
septum
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12. Compare and contrast a human somatic cell to a human gamete.
- Human somatic cells have 46 chromosomes, including 22 homologous pairs and one pair of nonhomologous sex chromosomes.
- This is the 2n, or diploid, condition.
- Human gametes have 23 chromosomes, one each of 23 unique chromosomes.
- This is the n, or haploid, condition.
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CHAPTER 6
13. Describe the similarities and difference between the cytokinesis mechanisms found in animal cells versus those in plant cells.
- In animal cells, a ring of actin fibers is formed around the periphery of the cell at the former metaphase plate.
- The actin ring contracts inward, pulling the plasma membrane toward the center of the cell until the cell is
- pinched in two.
- In plant cells, a new cell wall must be formed between the daughter cells. Because of the rigid cell walls of the parent cell,
- contraction of the middle of the cell is not possible.
- Instead, a cell plate is formed in the center of the cell at the former metaphase plate.
- The cell plate is formed from Golgi vesicles that contain enzymes, proteins, and glucose.
- The vesicles fuse and the enzymes build a new cell wall from the proteins and glucose.
- The cell plate grows toward, and eventually fuses with, the cell wall of the parent cell.
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CHAPTER 6
14. Outline the steps that lead to a cell becoming cancerous.
- If one of the genes that produce regulator proteins becomes mutated, it produces a malformed, possibly non-
- functional, cell-cycle regulator.
- This increases the chance that more mutations will be left unrepaired in the cell.
- Each subsequent generation of cells sustains more damage.
- The cell cycle can speed up as a result of loss of functional checkpoint proteins.
- The cells can lose the ability to self-destruct.
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15. Explain the difference between a proto- oncogene and a tumor suppressor gene.
- A proto-oncogene is the segment of DNA that codes for one of the positive cell-cycle regulators.
- If that gene becomes mutated to a form that is overactive, it is considered an oncogene.
- A tumor suppressor gene is a segment of DNA that codes for one of the negative cell-cycle regulators.
- If that gene becomes mutated to a form that is underactive, the cell cycle will run unchecked.
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CHAPTER 6
16. Name the common components of eukaryotic cell division and binary fission.
DNA duplication, segregation of duplicated chromosomes, and the division of the cytoplasmic contents.
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