5.1 Cell Increase and Decrease

• During the lifetime of an individual, mitosis causes somatic cells to increase in number and apoptosis causes them to decrease in number.
• Mitosis is part of the cell cycle. Specific events must take place for mitosis to occur.

1. What is apoptosis and what is its function?
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2. What three checkpoints help control the cell cycle?
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Essential Study Partner
    Cell Division Introduction
    Chromosomes

Art Quizzes
    Cell Cycle
    Mechanisms of Cell Cycle Control
    Nucleosomes

Explorations
    Mitosis: Regulating the Cell Cycle

5.2 Maintaining the Chromosome Number

• Each species has a characteristic number of chromosomes.
• Mitosis (a type of nuclear division) maintains the chromosome number in cells.
• Mitosis is necessary to the growth and repair of body cells.

1. What is the overall purpose of mitosis?
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2. What is cytokinesis?
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Essential Study Partner
    Mitosis/Cell Cycle

Animation Quiz
    Mitosis

Labeling Exercises
Mitosis Overview 1 (34.0K)
Mitosis Overview 2 (45.0K)
Plant Cell Mitosis (39.0K)

5.3 Reducing the Chromosome Number

• Meiosis (another type of nuclear division) reduces the chromosome number in life cycles involving sexual reproduction.
• Meiosis produces cells that have half the total number of chromosomes as the parental cell had.
• Meiosis produces cells that have different combinations of genes.

1. Name two ways that genetic recombination can occur during the process of meiosis.
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2. In general, how does meiosis I differ from meiosis II?
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Essential Study Partner
    Meiosis
    Recombination

Animation Quiz
    Meiosis

Explorations
    Exploring Meiosis: Down Syndrome

Labeling Exercise
Meiosis I (29.0K)

5.4 Comparison of Mitosis and Meiosis

• Meiosis differs from mitosis both in occurrence and in process.

1. Where in the body of a multicellular organism are meiosis and mitosis likely to occur?
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Essential Study Partner
    Review of Cell Division

Art Quiz
    Alternation of Generations

5.5 The Human Life Cycle

• The human life cycle includes both mitosis and meiosis.
• In humans, and many other animals, meiosis is a part of the production of sperm in males and eggs in females.
• When the sperm fertilizes the egg, the full number of chromosomes is restored in offspring.

1. What occurs during spermatogenesis and oogenesis?
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2. What is the function of polar bodies during oogenesis?
   Answer
   

Labeling Exercise
Sperm and Egg Anatomy (27.0K)