Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
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1. |
A gene is a segment of DNA that directs the production of RNA and protein. _________________________
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2. |
The information needed by a cell to direct its activities and to determine its characteristics is contained in molecules of protein. _________________________
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3. |
After the replication of a cell’s DNA, there are twice as many centromeres as there are chromatids. _________________________
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4. |
Cells that seldom divide spend most of their time in interphase. _________________________
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5. |
After mitosis and interphase, each new cell has a complete set of the parent cell’s chromosomes. _________________________
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6. |
In animal cells, cytokinesis results when a cell plate forms across the cell to divide the cytoplasm. _________________________
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7. |
Plant cells separate their cytoplasm during cytokinesis when protein threads pinch the cell in half. _________________________
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8. |
The cell cycle has four checkpoints that act to inhibit uncontrolled cell division. _________________________
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9. |
Offspring formed by asexual reproduction look exactly like their parent. _________________________
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10. |
In budding, new individuals develop from pieces of the original individual. _________________________
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11. |
Some eukaryotes reproduce asexually, and some produce sexually. _________________________
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12. |
In asexual reproduction, two parents each pass genetic material to their offspring. _________________________
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13. |
Asexual reproduction provides for genetic diversity, the raw material for evolution. _________________________
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14. |
Genetic diversity is the raw material for evolution. _________________________
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15. |
Genes on chromosomes are the units of inheritance. _________________________
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16. |
Each human somatic cell contains two copies of each chromosome for a total of 23 chromosomes. _________________________
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17. |
Gametes are diploid so that when fertilization occurs, the resulting zygote will have the characteristic number of chromosomes for that species. _________________________
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18. |
While paired together during the second division of meiosis, two chromosomes may exchange segments of DNA. _________________________
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19. |
Crossing-over is the exchange of corresponding portions of chromatids between homologous chromosomes. _________________________
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20. |
Random fertilization refers to the fact that homologous chromosomes are distributed randomly during meiosis. _________________________
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21. |
The process by which sperm are produced in male animals is called spermatogenesis. _________________________
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22. |
During the diploid life cycle, all of the cells are diploid. _________________________
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23. |
During the haploid life cycle, the zygote is the only diploid cell. _________________________
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24. |
In the life cycle of a plant, the gametophyte is the haploid phase that produces gametes by mitosis. _________________________
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25. |
A spore gives rise to a multicellular individual without joining with another cell. _________________________
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26. |
Moss plants have haploid life cycles. ______________________________
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Multiple Choice
Identify the choice that best completes the statement or answers the question.
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27. |
Which of the following is not a reason cells divide?
a.
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The cell gets too big to process and transport nutrients. |
b.
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New cells are needed for growth. |
c.
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DNA cannot be copied quickly enough in large cells. |
d.
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Surface area-to-volume ratio becomes too large. |
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28. |
The chromosome of a bacterium
a.
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is wrapped around proteins. |
b.
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has a circular shape. |
c.
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occurs in multiple pairs within the cell. |
d.
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is found within the nucleus. |
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29. |
The region of a chromosome where two sister chromatids are held together is called a
a.
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spindle. |
c.
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nucleosome. |
b.
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centromere. |
d.
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centriole. |
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30. |
Chromatids are
a.
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dense patches within the nucleus. |
b.
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bacterial chromosomes. |
c.
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joined strands of duplicated genetic material. |
d.
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prokaryotic nuclei. |
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31. |
When a chromosome condenses,
a.
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a histone wraps around chromatin. |
b.
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beads form on the DNA double helix. |
c.
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its centromere splits. |
d.
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looped domains coil into a structure. |
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32. |
In order to fit within a cell, DNA becomes more compact by
a.
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breaking apart into separate genes. |
b.
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extending to form very long, thin molecules. |
c.
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wrapping tightly around histones. |
d.
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being enzymatically changed into a protein. |
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33. |
In a bacterium, cell division takes place when
a.
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its nucleus divides. |
b.
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the cell splits into two cells, one of which receives all of the DNA. |
c.
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the DNA is copied, a new cell wall forms between the DNA copies, and the cell splits into two cells. |
d.
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spindle fibers form. |
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34. |
The phase of the cell cycle that occupies most of an average cell’s life is
a.
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G1. |
c.
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G2. |
b.
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mitosis. |
d.
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S. |
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35. |
What occurs after cytokinesis is completed?
a.
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The cell organizes its microtubules. |
c.
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The cell enters G1. |
b.
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The cell begins to replicate its DNA. |
d.
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The cell enters G2. |
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36. |
Which of the following shows the correct sequence of the cell cycle?
a.
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cytokinesis ® mitosis ® G1 ® S ® G2 |
b.
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S ® G1 ® G2 ® mitosis ® cytokinesis |
c.
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G1 ® S ® G2 ® mitosis ® cytokinesis |
d.
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mitosis ® G1 ® S® G2 ® cytokinesis |
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37. |
Cells that are not dividing remain in the
a.
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mitosis phase. |
c.
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first gap phase. |
b.
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synthesis phase. |
d.
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second gap phase. |
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38. |
The synthesis (S) phase is characterized by
a.
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DNA replication. |
b.
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cell division. |
c.
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replication of mitochondria and other organelles. |
d.
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the division of cytoplasm. |
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39. |
5 steps : the cell cycle ::
a.
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6 steps : prophase |
c.
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3 steps : meiosis |
b.
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9 steps : cytokinesis |
d.
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4 steps : mitosis |
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40. |
The first three phases of the cell cycle are collectively known as
a.
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a gap. |
c.
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mitosis. |
b.
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telophase. |
d.
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interphase. |
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41. |
cell growth : G1 ::
a.
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mitosis : cytokinesis |
b.
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mitosis : meiosis |
c.
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mitochondria replication : synthesis phase |
d.
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DNA copying : synthesis phase |
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42. |
metaphase : prophase ::
a.
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G1 : mitosis |
c.
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mitosis : cytokinesis |
b.
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G2 : S |
d.
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S : mitosis |
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43. |
Mitosis is the process by which
a.
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microtubules are assembled. |
b.
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cytoplasm is divided. |
c.
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the nucleus is divided into two nuclei. |
d.
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the cell rests. |
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44. |
A spindle fiber is a specialized form of
a.
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microtubule. |
c.
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centriole. |
b.
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centrosome. |
d.
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chromosome. |
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45. |
The phase of mitosis that is characterized by the arrangement of all chromosomes along the equator of the cell is called
a.
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telophase. |
c.
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anaphase. |
b.
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metaphase. |
d.
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prophase. |
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46. |
Refer to the illustration above. The cell in diagram 1 is in
a.
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metaphase. |
c.
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anaphase. |
b.
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telophase. |
d.
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prophase. |
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47. |
Refer to the illustration above. Mitosis begins with the stage shown in diagram
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48. |
Refer to the illustration above. The cell shown in diagram 5 is in
a.
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metaphase. |
c.
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anaphase. |
b.
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telophase. |
d.
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prophase. |
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49. |
Refer to the illustration above. Which of the following correctly indicates the order in which these events occur?
a.
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A, B, C, D |
c.
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B, A, C, D |
b.
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C, B, A, D |
d.
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A, C, B, D |
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50. |
Refer to the illustration above. During which stage do the centromeres divide?
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51. |
As a result of mitosis, each of the two new cells produced from the parent cell during cytokinesis
a.
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receives a few chromosomes from the parent cell. |
b.
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receives an exact copy of all the chromosomes present in the parent cell. |
c.
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donates a chromosome to the parent cell. |
d.
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receives exactly half the chromosomes from the parent cell. |
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52. |
Cytokinesis in plant cells involves the formation of
a.
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a belt of protein threads. |
c.
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spindle fibers. |
b.
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a cell plate. |
d.
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centrioles. |
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53. |
Which of the following statements is true?
a.
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Prokaryotes divide by mitosis. |
b.
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Eukaryotes have circular chromosomes. |
c.
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Animal cells form new cell walls when they divide. |
d.
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Plant cells and animal cells have different strategies for cytokinesis. |
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54. |
In eukaryotes, the cell cycle is controlled by
a.
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proteins. |
c.
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lipids. |
b.
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carbohydrates. |
d.
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fats. |
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55. |
At the G2 checkpoint, DNA replication is checked by
a.
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receptor proteins. |
c.
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repair enzymes. |
b.
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electron transport chains. |
d.
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cell-surface markers. |
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56. |
The cell cycle is monitored as each cell passes through
a.
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the S phase. |
c.
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the interphase checkpoint. |
b.
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checkpoints. |
d.
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cytokinesis. |
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57. |
Normal cells become cancer cells when
a.
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regulation of cell growth and division occurs. |
b.
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cells respond to control mechanisms. |
c.
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cells pass through G1. |
d.
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cells do not respond to checkpoints. |
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58. |
Which of the following is not a type of asexual reproduction?
a.
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budding |
c.
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binary fission |
b.
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fragmentation |
d.
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fertilization |
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59. |
Hydras reproduce by
a.
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budding. |
c.
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binary fission. |
b.
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fragmentation. |
d.
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parthenogenesis. |
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60. |
Budding is an example of
a.
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endosymbiosis. |
c.
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meiosis. |
b.
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asexual reproduction. |
d.
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sexual reproduction. |
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61. |
The simplest and most primitive method of reproduction is
a.
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sexual. |
c.
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haploid. |
b.
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diploid. |
d.
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asexual. |
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62. |
Binary fission
a.
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occurs when two cells collide with each other. |
b.
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produces excess energy. |
c.
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creates new species. |
d.
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is the process by which bacteria reproduce. |
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63. |
The process of producing offspring is called reproduction and can be
a.
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eukaryotic or prokaryotic. |
c.
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zygotic or gametic. |
b.
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asexual or sexual. |
d.
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haploid or diploid |
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64. |
Sexual reproduction includes
a.
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budding. |
c.
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binary fission. |
b.
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fragmentation. |
d.
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fertilization |
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65. |
Normal human males develop from fertilized eggs containing which of the following sex chromosome combinations?
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66. |
Homologous chromosomes are pairs of chromosomes containing genes that code for
a.
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different traits. |
c.
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DNA. |
b.
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the same traits. |
d.
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sex. |
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67. |
In humans, gametes contain
a.
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22 autosomes and 1 sex chromosome. |
b.
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1 autosome and 22 sex chromosomes. |
c.
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45 autosomes and 1 sex chromosome. |
d.
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1 autosome and 45 sex chromosomes. |
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68. |
In humans, the male determines the sex of the child because males have
a.
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two X chromosomes. |
c.
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two Y chromosomes. |
b.
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one X and one Y chromosome. |
d.
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46 chromosomes. |
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69. |
The X and Y chromosomes are called
a.
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extra chromosomes. |
c.
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sex chromosomes. |
b.
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homologous chromosomes. |
d.
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autosomes. |
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70. |
female : XX ::
a.
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female : gametes |
c.
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male : YY |
b.
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female : eggs |
d.
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male : XY |
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71. |
How many chromosomes are in the body cells of an organism that has a haploid number of 8?
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72. |
The diploid number of chromosomes in a human skin cell is 46. The number of chromosomes found in a human egg cell is
a.
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46. |
c.
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23. |
b.
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92. |
d.
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12.5. |
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73. |
diploid : somatic cell :: haploid :
a.
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body cell |
c.
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gamete |
b.
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chromosome |
d.
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zygote |
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74. |
A haploid cell is one that
a.
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has two homologues of each chromosome. |
b.
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is designated by the symbol 2n. |
c.
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has chromosomes found in pairs. |
d.
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has one set of chromosomes. |
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75. |
Refer to the illustration above. The process shown is
a.
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mitosis. |
c.
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meiosis. |
b.
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chromosomal mutation. |
d.
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dominance. |
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76. |
Separation of homologues occurs during
a.
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mitosis. |
c.
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meiosis II. |
b.
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meiosis I. |
d.
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fertilization. |
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77. |
When crossing-over takes place, chromosomes
a.
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mutate in the first division. |
b.
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produce new genes. |
c.
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decrease in number. |
d.
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exchange corresponding segments of DNA. |
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Using the information you have learned about cell reproduction, infer answers to the questions below about a cell with a diploid number of 4 chromosomes. Select from among the diagrams below, labeled A, B, C, D, and E, to answer the questions.
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78. |
Which of the diagrams above depicts a cell at the end of meiosis I?
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79. |
Which of the diagrams above depicts a cell at the end of meiosis II?
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80. |
Which of the diagrams above depicts a cell at the beginning of mitosis?
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81. |
Which of the diagrams above depicts a cell at the end of mitosis?
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82. |
The difference between anaphase of mitosis and anaphase I of meiosis is that
a.
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the chromosomes line up at the equator in anaphase I. |
b.
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centromeres do not exist in anaphase I. |
c.
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chromatids do not separate at the centromere in anaphase I. |
d.
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crossing-over occurs only in anaphase of mitosis. |
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83. |
The exchange of segments of DNA between the members of a pair of chromosomes
a.
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ensures that variations within a species never occur. |
b.
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acts as a source of variations within a species. |
c.
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always produces genetic disorders. |
d.
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is called genetic crossing. |
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84. |
Crossing-over occurs
a.
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during prophase II. |
c.
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during prophase I. |
b.
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during fertilization. |
d.
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at the centromere. |
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85. |
Which of the following does not provide new genetic combinations?
a.
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random fertilization |
c.
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independent assortment |
b.
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cytokinesis |
d.
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crossing-over |
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86. |
During cytokinesis in the female, what divides unequally?
a.
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the sperm cell |
c.
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the cytoplasm |
b.
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the ovary |
d.
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the DNA |
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87. |
The more common name for an ovum is a(n)
a.
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egg. |
c.
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nutrient. |
b.
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hormone. |
d.
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polar body. |
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88. |
To create new haploid cells during the haploid life cycle, the zygote undergoes
a.
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mitosis. |
c.
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fusion. |
b.
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fertilization. |
d.
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meiosis. |
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89. |
Which of the following is not a type of sexual life cycle?
a.
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alternation of generations |
c.
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diploid |
b.
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haploid |
d.
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parthenogenesis |
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90. |
In alternation of generations, a diploid spore-forming cell gives rise to four
a.
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zygotes. |
c.
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haploid spores. |
b.
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sperm cells. |
d.
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diploid spores. |
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91. |
During alternation of generations, cells reproduce by
a.
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meiosis only. |
c.
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both meiosis and mitosis. |
b.
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mitosis only. |
d.
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binary fission. |
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Completion
Complete each statement.
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92. |
Growth occurs through cell enlargement and cell ____________________.
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93. |
The DNA in eukaryotic cells is packaged into structures called ____________________.
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94. |
A duplicated chromosome consists of two identical ____________________, which are held together at the centromere.
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95. |
The sequence of events that occurs in a cell from one cell division to the next is called the ____________________.
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96. |
Collectively, the time spent in G1 + S + G2 is called ____________________.
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97. |
A cell’s DNA is copied during the ____________________ phase.
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98. |
Cells that are not dividing remain in the ____________________ phase.
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99. |
Spindle fibers are made of hollow tubes of protein called ____________________.
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100. |
The spindle is assembled by the ____________________.
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101. |
In most eukaryotic cells, ____________________ takes place after the nucleus divides.
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102. |
In plant cells, a(n) ____________________ forms in the center of the cell during cytokinesis.
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103. |
Normal cell growth and cell division are regulated by ____________________.
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104. |
The cell cycle is controlled in eukaryotes at three principal ____________________.
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105. |
Loss of control and regulation of the ____________________ can result in the development of cancer.
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106. |
The separation of a parent into two or more individuals of about equal size is called ____________________.
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107. |
Binary fission is the process by which ____________________ split asexually into two identical organisms.
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108. |
Only ____________________ cells can produce gametes.
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109. |
Somatic cells containing two sets of 23 chromosomes each are always ____________________.
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110. |
After a new nuclear membrane forms during telophase I of meiosis, the ____________________ divides, resulting in two cells.
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111. |
The process called ____________________ guarantees that the number of chromosomes in gametes is half the number of chromosomes in body cells.
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112. |
Prophase I of meiosis is different from prophase of mitosis in that every chromosome pairs with its ____________________.
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113. |
A reciprocal exchange of corresponding segments of DNA is called ____________________ – ____________________.
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114. |
The four haploid cells formed in the male at the end of meiosis II develop tails and are called ____________________.
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115. |
The diploid number of chromosomes is re-established through ____________________.
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116. |
In a haploid life cycle, ____________________ results in the first cell of a multicellular haploid organism.
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