The Cell Cycle Guided Reading

Transcription

1 Name Date Period 1. List three things that multi-celled organisms need cell division for. a. b. c. 2. Why do single-celled organisms need to go through cell division? 3. What is the cell cycle? 4. True or False: All cells go through the cell cycle in the same amount of time. Some cells in the human body do not undergo mitosis and cannot repair themselves. 5. Cells that undergo mitosis spend of their time in interphase. 6. During interphase, the most important thing that takes place is 7. Why is it important for a cell to copy its genetic material before dividing? 1

2 The Stages of Interphase Complete the chart detailing the stages of interphase. Color and label each portion of the chart and diagram the color given. Color Phase description none Gap 0 G 0 blue Gap 1 G 1 red Synthesis S green Gap 2 G 2 purple Mitosis M 2

3 Mitosis Complete the diagram by cutting out the pictures and descriptions on the last page and gluing them in the correct order to show the phases of mitosis. 3

4 After mitosis is complete, there is one step left before the two cells can completely separate from each other. This process in which the cytoplasm divides is called cytokinesis. Under each picture, describe what is happening. 27. What are two important things should remember about mitosis? a. b. 28. What can happen if a mistake occurs during mitosis? 4

5 29 During mitosis, DNA is copied and passed on to new cells. In which part of the cell is this hereditary material located? A cell membrane B cytoplasm C nucleus D cell wall 30 During which phase of mitosis do the two separate nuclei appear? A telophase B anaphase C early prophase D late prophase 31 Based on the process shown in the diagram above, which of the following is a valid conclusion? A First the cells divide, then mitosis occurs, and then the chromosomes are copied. B First mitosis occurs, then the cells divide, and then mitosis occurs again. C First the chromosomes are copied, then endocytosis occurs, and then the cells divide. D First the chromosomes are copied, then mitosis occurs, and then the cells divide. 5

6 32 If you damage your skin, what process do your cells use to make repairs (scabs and new skin)? A spontaneous generation B mitosis and cytokinesis C meiosis D the cell theory 33 What would happen to an organism if it s cells could no longer undergo mitosis? A nothing B it would grow larger C it would stop growing and die D it would shrink 34 Beginning with interphase, what are the phases of mitosis in order? A telophase, anaphase, metaphase, prophase B anaphase, metaphase, prophase, telophase C prophase, anaphase, metaphase, telophase D prophase, metaphase, anaphase, telophase 35 Which drawing represents interphase? A 4 B 3 C 2 D 1 6

7 36 In which phase of the cell cycle do cells spend 95% of their time? A metaphase B anaphase C interphase D prophase 37 After mitosis is complete, how are the two cells alike? A they both have double the chromosomes B they are identical copies of each other C the new cell has half the DNA D one cell is newer than the other 38 Your body has a layer of skin that protects it from the environment. This layer of skin is made up of many individual skin cells. Explain where all the cells came from and how two individual cells share the same traits. 7

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9 telophase prophase metaphase anaphase each centromere divides and the spindle fibers shorten. Each pair of chromatids seperates, and chromatids begin to move to opposite ends of the cell. The seprated chromatids are now called chromosomes. spindle fibers start to disappear, the chromosomes start to uncoil, and a new nucleus forms. the pairs of chromatids are fully visible when viewed under a microscope. The nucleolus and nuclear membrane disappear. Two small structures called centrioles move to opposite ends of the cell. Between the centrioles, threadlike spindle fibers begin to stretch across the cell. pairs of chromatids line up across the center of the cell. The centromere of each pair usually becomes attached to two spindle fibers one from each side of the cell. 9