CELL REPRODUCTION Practice Exam

Transcription

1 CELL REPRODUCTION Practice Exam TRUE/FALSE 1. The information needed by a cell to direct its activities and to determine its characteristics is contained in molecules of protein). 2. Prokaryotic chromosomes are contained within a nucleus, while eukaryotic chomosomes are not. 3. Each human somatic/diploid cell contains two copies of each chromosome for a total of 46 homologous chromosomes. 4. Human sperm and egg cells have 46 chromosomes. 5. Gametes are haploid so that when fertilization occurs, the resulting zygote will have the characteristic number of chromosomes for that species. 6. Cell division in bacteria and eukaryotes takes place by way of different processes. 7. Cells spend most of their lifetime in the mitotic phase. 11. During anaphase, a nuclear envelope surrounds each new set of chromosomes. 12. Chromatids separate from each other during metaphase. 13. After mitosis and cytokinesis, each new cell has an incomplete and genetically different set of the original cell s chromosomes. 14. Plant cells cannot undergo cell division because of their strong cell walls. 15. Cytokinesis occurs following telophase. It is the separation of the cytoplasm and represents cell division. 16. Meiosis results in the formation of diploid cells from haploid cells. 17. Meiosis produces four nuclei that are genetically identical to the original cell s nucleus. 18. While paired in tetrad formation during prophase 1 of meiosis, two homologous chromosomes may exchange segments of DNA. 19. The exchange of reciprocal segments of DNA between homologous chromosomes during the first stage of meiosis is called the eukaryotic intercellular gene exchange. MULTIPLE CHOICE 1. DNA becomes more compact a. by breaking apart into separate genes. b. by extending to form very long, thin molecules. c. in order to fit within a cell by wrapping tightly around associated proteins. d. by being enzymatically changed into a protein.

2 2. Joined strands of duplicated genetic material are called a. diplogenetistrands. b. spermatids. c. chromatids. d. clonatids. 3. A centromere is a. equal to 100 mere s. c. merely a centro. b. a protein disk that attaches two chromatids d. an organelle found only in animal cells that to each other in a chromosome. assists in cell division by helping to organize the arrangement of the protein spindle fibers. 4. Which of the following is a true difference between the chromosomes of eukaryotes and those of prokaryotes? a. Eukaryotic chromosomes are linear, while those of prokaryotes are circular. b. Eukaryotic chromosomes are associated with histones, while those of prokaryotes are not. c. Eukaryotes usually have more than one chromosome, while prokaryotes have only one chromosome. d. All of the above 5. Chromosomes that exist in 23 pairs, contain thousands of genes and are about 40 percent DNA and 60 percent protein, are found in a. your body. b. only extraterrestrial organisms. c. prokaryotes. d. all eukaryotes. 6. A student can study a karyotype to learn about the a. molecular structure of a chromosome. b. genes that are present in a particular strand of DNA. c. medical history of an individual. d. chromosomes present in a somatic cell. 7. A haploid cell is one that a. has two homologues of each chromosome. b. is designated by the symbol 1n. c. has chromosomes found in pairs. d. All of the above 8. The diploid number of chromosomes in a human skin cell is 46. The number of chromosomes found in a human liver cell is a. 46. c. 23. b. 92. d How many chromosomes are in the body cells of an organism that has a haploid number of 4? a. 4 c. 12 b. 8 d. 16

3 11. The process by which bacteria reproduce is known as a. prokaryosplicing. b. meiosis. c. bacterioduplicato. d. binary fission 12. Circular shaped chromosomes are found in a. eukaryotes. b. bacterium. c. ring worms. d. people who have difficulty making decisions. 13. In a bacterium, cell division takes place when a. its nucleus divides. b. the cell splits into two cells, one of which receives all of the DNA. c. the DNA is copied, a new cell wall forms between the DNA copies, and the cell splits into two cells. d. strong opinions surface. 14. The stage of the cell cycle that occupies most of the cell s life is a. G1. c. G2. b. M. d. S. 15. Which of the following shows the correct sequence of the cell cycle? a. C M G1 S G2 c. G1 S G2 M C b. S G1 G2 M C d. None of the above 16. growth : G1 :: a. mitosis : meiosis c. cytokinesis : M b. mitochondria replication : S d. DNA copying : S 17. prophase : metaphase :: a. G1 : S c. Brady : Moss b. G2 : S d. a & c 18. The phase of mitosis that is characterized by the arrangement of all chromosomes along the equator of the cell is called a. telophase. c. anaphase. b. metaphase. d. prophase. 19. A spindle fiber is a specialized form of a. microtubule. c. cilium. b. flagellum. d. chromosome.

4 A DIF: I OBJ: Refer to the illustration above. The cell in diagram 1 is in a. metaphase. c. anaphase. b. telophase. d. prophase. 21. Refer to the illustration above. Mitosis begins with the stage shown in diagram a. 1. c. 3. b. 2. d Refer to the illustration above. The cell shown in diagram 5 is in a. metaphase. c. anaphase. b. telophase. d. prophase. 23. A typical human cell contains 46 chromosomes. After mitosis and cell division, each of the two new cells formed from the original cell a. gets 23 chromosomes. b. grows new chromosomes from existing DNA. c. gets a complete set of 46 chromosomes. d. None of the above 24. As a result of mitosis, each of the two new cells produced from the original cell during cytokinesis a. receives a few chromosomes from the original cell. b. receives an exact copy of all the chromosomes present in the original cell. c. donates a chromosome to the original cell. d. receives exactly half the chromosomes from the original cell. 25. Refer to the illustration above. Which of the following correctly indicates the order in which these events occur? a. A, B, C, D c. B, A, C, D b. C, B, A, D d. A, C, B, D 26. Refer to the illustration above. During which stage do the centromeres divide? a. A c. C b. B d. D : cell cycle :: a. 6 : prophase c. 3 : meiosis b. 9 : cytokinesis d. 4 : mitosis

5 28. A new cell wall forms in plant cells a. as a reinforcement to the existing wall in response to increased noise level outside the cell. b. when the old one falls down. c. when cytokinesis occurs. d. when metaphase occurs. 29. Mitosis is a process by which a. DNA is replicated. c. cells grow in size. b. cytokinesis occurs. d. a cell s nucleus divides. 30. Which of the following statements is true? a. Prokaryotes divide by mitosis. b. Eukaryotes have circular chromosomes. c. Animal cells form new cell walls when they divide. d. Cytokinesis differs in plant cells and animal cells. 31. Crossing over of homologues occurs during a. anaphase 1 of meiosis. c. prophase 2 of meiosis. b. prophase 1 of meiosis. d. The moment at which the homologue dies. 32. The difference between anaphase of mitosis and anaphase I of meiosis is that a. the chromosomes line up at the equator in anaphase I. b. centromeres do not exist in anaphase I. c. chromatids do not separate at the centromere in anaphase I. d. crossing-over occurs only in anaphase of mitosis. Diagrams A and B show cells from an organism with a diploid chromosome number of Refer to the illustration above. Which of the cells will be a diploid cell at the completion of division? a. A c. Both b. B d. Neither 34. Refer to the illustration above. Which of these cells is in the process of dividing to form gametes? a. A c. Both b. B d. Neither 35. Homologues exchange corresponding segments of DNA a. When a fair agreement is reached. b. only during the bimomentary inter-transcellular trade fair. c. when crossing-over takes place in prophase 2 of meiosis. d. when crossing-over takes place in prophase 1 of meiosis. 36. The exchange of segments of DNA between the members of a pair of chromosomes

6 a. ensures that variation within a species never occurs. b. acts as a source of variation within a species. c. always produces genetic disorders. d. is called crossing. COMPLETION 1. Following replication of its DNA, each chromosome contains two, which are attached to each other by a centromere. 2. Chromosomes that are not involved in sex determination are called. 3. A picture of a cell s chromosomes is called a. 4. is the process by which bacteria split asexually into two identical organisms. 5. In bacteria, cell division takes place in two stages. First the is copied, and then the cell splits. 6. The sequence of events that occurs in a cell from one mitotic division to the next is called the. 7. Collectively, the time spent in G1 + S + G2 is called. 8. Cables made of microtubules that extend from the poles of a cell to the centromeres during cell division are called. 9. In mitosis, anaphase follows. 10. Chromosomes coil up into short, fat rods during. 11. During cell division, plant cells form a new in the center of the cell. 12. In eukaryotic cells, takes place after the nucleus divides. 13. The stage of meiosis during which homologues line up along the equator of the cell is called. 14. After a new nuclear membrane forms during telophase of mitosis or meiosis, the divides, resulting in two cells. 15. The process called guarantees that the number of chromosomes in gametes is half the number of chromosomes in body cells. 16. A reciprocal exchange of corresponding segments of DNA is called. 17. The cells resulting from meiosis in either males or females are called. 18. As a result of spermatogenesis, cells are produced that can all develop into sperm cells. As a result of oogenesis, only cell(s) develop(s) into (an) egg cell(s).

7 ESSAY 1. Refer to the illustration above. Identify the structure in the diagram and discuss its importance during eukaryotic cell division. Write your answer in the space below. This is a chromosome, which is made of DNA. During mitosis, the process that precedes eukaryotic cell division, the nucleus of a cell divides into two nuclei, each containing a complete set of the cell's chromosomes. Thus, each new cell formed during cell division contains identical DNA. DIF: II OBJ: What would happen if the chromosome number were not reduced before sexual reproduction? Write your answer in the space below. The number of chromosomes in the offspring would be double the number in the parents. The number and characteristics of chromosomes in cells determine the traits of the organism. The organism would almost certainly not survive the doubling of its chromosomes, and even if it did survive and reproduce, then the number of chromosomes would become unmanageably large after only a few generations. DIF: II OBJ: Briefly describe the five stages of the cell cycle. Write your answer in the space below.

8 The G1 stage of the cell cycle is the phase of cell growth. This is followed by the S stage, during which DNA is copied. G2 involves the cell preparing for cell division. The M phase is when mitosis occurs. The cell cycle concludes with the C stage, during which cytokinesis takes place. The newly formed cells then enter into a new cell cycle, repeating these stages again. DIF: II OBJ: Compare the features of mitotic metaphase, meiotic metaphase I, and meiotic metaphase II. Write your answer in the space below. During metaphase of mitosis, the diploid number of chromosomes of the cell line up single file across the equator of the cell. Meiotic metaphase I is characterized by the homologous chromosomes lining up as pairs (double file) along the equator. Metaphase II of meiosis appears similar to mitotic metaphase, except that the number of chromosomes is the haploid number rather than the diploid number. These chromosomes line up single file across the cell equator. DIF: II OBJ: Identify three ways in which genetic recombination results during meiosis. Write your answer in the space below. Genetic recombination results when crossing-over occurs between homologues or between chromatids, when homologous pairs separate independently in meiosis I, or when sister chromatids separate independently in meiosis II. DIF: II OBJ: 8-3.3