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# 5.1: Cell Division and the Cell Cycle

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## Lesson 5.1: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Cell division is basically the same in prokaryotic and eukaryotic cells.

_____ 2. Cytokinesis is the division of the cytoplasm.

_____ 3. Mitosis is the process in which the nucleus of the cell divides.

_____ 4. DNA replication results in identical chromosomes.

_____ 5. A cell spends most of its life in growth phase 1 of the cell cycle.

_____ 6. The S checkpoint, just before entry into S phase, makes the key decision of whether the cell should divide.

_____ 7. The correct order of phases of the cell cycle is G1 → S → G2 → M.

_____ 8. Interphase consists of mitosis and cytokinesis.

_____ 9. In prokaryotic cells, all organelles, such as the Golgi apparatus and endoplasmic reticulum, divide prior to cell division.

_____ 10. Bacteria divide cells by binary fusion.

_____ 11. A mass of abnormal cells is called a tumor.

_____ 12. Organelles are made during growth phase 2.

_____ 13. In eukaryotic cells, DNA is replicated during the S phase of the cell cycle.

_____ 14. If the cell cycle is not regulated, cancer may develop.

_____ 15. Mitosis occurs in both prokaryotic and eukaryotic cells.

Name___________________ Class______________ Date________

Read these passages from the text and answer the questions that follow.

The Cell Cycle

Cell division is just one of several stages that a cell goes through during its lifetime. The cell cycle is a repeating series of events, including growth, DNA synthesis, and cell division. The cell cycle in prokaryotes is quite simple: the cell grows, its DNA replicates, and the cell divides. In eukaryotes, the cell cycle is more complicated.

Eukaryotic Cell Cycle

The diagram in the figure below represents the cell cycle of a eukaryotic cell. As you can see, the eukaryotic cell cycle has several phases. The mitosis phase (M) actually includes both mitosis and cytokinesis. This is when the nucleus and then the cytoplasm divide. The other three phases (G1, S, and G2) are generally grouped together as interphase. During interphase, the cell grows, performs routine life processes, and prepares to divide. These phases are discussed below.

Eukaryotic Cell Cycle. This diagram represents the cell cycle in eukaryotes. The G1, S, and G2 phases make up interphase (I). The M phase includes mitosis and cytokinesis. After the M phase, two cells result. (Image courtesy of CK-12 Foundation and under the Creative Commons license CC-BY-NC-SA 3.0.)

Interphase

Interphase of the eukaryotic cell cycle can be subdivided into the following three phases, which are represented in the figure above:

• Growth Phase 1 (G1): During this phase, the cell grows rapidly, while performing routine metabolic processes. It also makes proteins needed for DNA replication and copies some of its organelles in preparation for cell division. A cell typically spends most of its life in this phase.
• Synthesis Phase (S): During this phase, the cell’s DNA is copied in the process of DNA replication.
• Growth Phase 2 (G2): During this phase, the cell makes final preparations to divide. For example, it makes additional proteins and organelles.

Cancer and the Cell Cycle

Cancer is a disease that occurs when the cell cycle is no longer regulated. This may happen because a cell’s DNA becomes damaged. Damage can occur because of exposure to hazards such as radiation or toxic chemicals. Cancerous cells generally divide much faster than normal cells. They may form a mass of abnormal cells called a tumor. The rapidly dividing cells take up nutrients and space that normal cells need. This can damage tissues and organs and eventually lead to death.

Questions

1. What is the cell cycle?

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2. What are the phases of the eukaryotic cell cycle?

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3. In which phase does a cell spend most of its life? What happens during this phase?

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4. What is cancer? What may cause cancer to occur?

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5. What is the S phase? What happens during this phase?

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## Lesson 5.1: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. Which cells undergo cell division?
1. prokaryotic cells only
2. eukaryotic cells only
3. cancer cells only
4. both prokaryotic and eukaryotic cells
2. Cell division in eukaryotic cells is a complex process because of
1. the multiple chromosomes.
2. the nucleus.
3. the many organelles.
4. all of the above
3. Most routine metabolic processes occur during which phase of the cell cycle?
1. growth phase 1
2. the S phase
3. growth phase 2
4. the M phase
4. The correct order of the eukaryotic cell cycle is
1. G1 → G2 → S → M.
2. S → G1 → G2 → M.
3. M → G1 → S → G2.
4. G1 → S → G2 → M.
5. The correct order of prokaryotic cell division is
1. cytokinesis → DNA replication → chromosome segregation.
2. DNA replication → chromosome segregation → cytokinesis.
3. growth → DNA replication → mitosis.
4. DNA replication→ mitosis → cytokinesis.
6. Which cell cycle checkpoint determines whether the DNA has been replicated correctly?
1. the cell growth checkpoint
2. the DNA synthesis checkpoint
3. the mitosis checkpoint
4. the G2 checkpoint
7. What happens during mitosis?
1. The nucleus of the cell divides.
2. The cytoplasm of the cell divides.
3. The cell divides.
4. The DNA replicates.
8. Cell division in prokaryotic cells is called
1. binary fission.
2. binary fusion.
3. mitosis.
4. cytokinesis.

## Lesson 5.1: Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions

_____ 1. the process in which one cell divides to form two daughter cells

_____ 2. the process in which all of the nuclear DNA is copied

_____ 3. a repeating series of events that describes the life of a cell

_____ 4. phase of the cell cycle that includes the G1, S, and G2 phases

_____ 5. the process by which bacterial cells divide

_____ 6. phase of the cell cycle in which the cell's DNA is copied

_____ 7. occurs when the cell cycle is no longer regulated

_____ 8. phase of the cell cycle in which the cell grows rapidly and performs many metabolic processes

_____ 9. phase of the cell cycle in which the cell makes final preparations to divide.

_____ 10. division of the cytoplasm, resulting in two daughter cells

_____ 11. an abnormal mass of cells

_____ 12. the process in which the nucleus of the cell divides

Terms

a. binary fission

b. cancer

c. cell cycle

d. cell division

e. cytokinesis

f. DNA replication

g. growth Phase 1

h. growth phase 2

i. interphase

j. mitosis

k. synthesis phase

l. tumor

## Lesson 5.1: Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. Cancer is a disease that occurs when the ____________ is no longer regulated.

2. During ____________, the nucleus of the cell divides.

3. ____________ consists of the G1, S, and G2 phases of the cell cycle.

4. During the ____________ phase, the cell’s DNA is copied in the process of DNA replication.

5. Cell division in ____________ occurs by binary fission.

6. During mitosis, the ____________ are sorted and separated to ensure that each daughter cell receives a complete set.

7. During cytokinesis, the ____________ divides.

8. ____________ in the cell cycle ensure that the cell is ready to proceed before it moves on to the next phase of the cycle.

9. After cell division, the new cells are referred to as ____________ cells.

10. Chromosome ____________ refers to the two chromosomes separating and moving to opposite ends of the cell.

11. In eukaryotes, the first step in cell division is ____________, and the second step is cytokinesis.

12. The cell cycle is controlled by regulatory ____________ at three key checkpoints.

## Lesson 5.1: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Describe the eukaryotic cell cycle, listing and discussing the main events of each phase.

Feb 23, 2012

Jan 04, 2015